Manufacturing for Exploration

Home , European Service Module, Expedition 44, Iranian Space Agency, Nauka (ISS module), Rassvet (ISS module), Steven Swanson

Final Report International Space University MSS Program 2019 This MSS 2019 Team Project work was conducted at the ISU Strasbourg Central Campus in Illkirch- Graffenstaden, France

The front cover is an original piece created by Lord Jim Tuohy. It is titled ‘Manufacturing for Exploration’. Inspired by the ideas put forward in the report, it encompasses the idea that in-space manufacturing is creating a path to enable human deep space exploration.

The Executive Summary and the Final report may be found on the ISU web site at http://www.isunet.edu in the “ISU Team Projects/Student Reports” section. Paper copies of the Executive Summary and the Final Report may also be requested, while supplies last, from:

International Space University Strasbourg Central Campus Attention: Publications/Library Parc d’Innovation 1 rue Jean-Dominique Cassini 67400 Illkirch-Graffenstaden France Publications: Tel +33 (0)3 88 65 54 32 Fax +33 (0)3 88 65 54 47 e-mail: [email protected]

Acknowledgments

The Manufacturing for Exploration team would like to thank our Faculty Interface Prof. Vasilis Zervos, for expanding our vision for the report.

The team would also like to expresses its gratitude to the faculty, Prof. Chris Welch, Prof. Volker Damann, Prof. Taiwo Tejumola, Prof. Hugh Hill, Ms. Danijela Stupar, Prof. Gongling Sun and Dr. Omar Hatamleh, and teaching assistants in ISU Ms. Ana Garduño Baltazar, Mr. Hameed Mohamed, and Mr. James Hurrell, who with their valuable suggestions, guidance, and feedback, helped us immensely to produce the final report.

Special thanks to ISU Librarian Ms. Muriel Riester, ISU IT staff, Mr. Nicolas Moncussi and Mr. Joel Herman, ISU Administration, Ms. Claire Byrski and Ms. Christine Jenck, for granting us access to all the ISU facilities and services.

We would especially like to thank Abeba Birhane from University College Dublin, James Baltitude from OrbitFab, Xavier Fruh from BeAM Machines, Stefan Siarov from Valispace, Pasi Vainikka and Juha-Pekka Pitkänen from Solar Foods Ltd., and Lord Jim Tuohy for sharing their invaluable experiences and opinions with us. Their contribution and assistance were of great value to the project.

Faculty Interface Dr. Vasilis Zervos Dr. Taiwo Tejumola

Teaching Associate James Hurrell

Authors

Marc Abi-Fadel Mazin Al Harbi

Miguel Chafen Tongtong Chen

Alexandria Farias Sarah Halpin

Zhuhui Jiang Sara Khan

Jue Liu Matthew McGrath

Adam Nawal Kuren Patel

Adi Rahamimoff Stephanie Rocha

Ignaty Romanov-Chernigovsky Daniel Rotko

Eóin Tuohy Héloïse Vertadier

Hannah Woodward

Faculty Preface

On Behalf of the ISU Faculty:

Innovation and technological change are intrinsically linked with the space sector, which though faced by definitional challenges, is nonetheless typically perceived entailing space components manufactured on Earth. Emerging technologies and developments in various fields lead to expanding the concept of space sector and industry, by emerging in-space manufacturing and 3D printing applications. The state of the art and applications feasibility of such concepts in the near and distant future is a task requiring research and synthesis within an interdisciplinary intercultural and international environment, fitting to the nature of ISU. Thus, a group of approximately twenty ISU Masters students in 2018/2019 embarked into the unknown in an effort to expand frontiers and exploit the options for a truly ‘’space-based’’ industry. As is often the case, the hard work and struggle associated with expanding frontiers is rarely felt by the authors into an environment where a perfect idea is the enemy of a good one. For them, the critical mass of research-amazed knowledge is the perfect complement to a report that provides an invaluable insight for the space sector and community. The report and auxiliaries provide a comprehensive approach to the outer space manufacturing challenges with existing and future applications and demands. Starting from the ISS and moving into future exploration scenarios supporting distant missions seems by now quite familiar with the authors who have covered significant distance in a short time. As for the faculty, we are grateful, for there is little more than positive experiences and knowledge obtained from our interactions with the group. We wish them the best, along with this and future works that will confidently challenge and add value to the space and wider society.

Professor Vasilis Zervos

Team Preface

In 2018 our group was formed to examine and explore the topic of, in-space manufacturing. Our team was composed of nineteen Masters students at the International Space University (ISU). In keeping with ISU’s 3Is program aims (Intercultural, Interdisciplinary and International work) we came from fourteen different academic backgrounds and fifteen different nationalities. Our goal was to create a team capable of meeting deliverable goals of communicating our findings on the topic in hand.

We discovered quickly that in-space manufacturing is a far reaching subject, an excellent example of a topic requiring a multidisciplinary approach. After spending time learning more about our new teammates strengths and skills, we voted on the creation of a team structure thus developing our management team consisting of our Project Manager, Faculty Interface and Chief Editor to support our efforts. Other team members’ roles remained fluid to meet the needs of the work. The output from our research is indebted to the dynamic and dedicated work of our team. Through the last six months we have learnt from each other and grown in the skills critical to the successful completion of this work.

No man or woman is an island, this is particularly true when attempting to develop a critical mass of knowledge on a previously unknown topic. When spending six months exploring such a vast topic it is easy to come to crossroads, dead ends and roundabouts. We remain immensely grateful to all who kindly offered their time and expertise to allow us to find our way through.

Humanity appears to be looking to the skies again, dreaming of space exploration and innovated techniques. Terrestrial based 3D printing and manufacturing techniques continue to show huge potential to be of significant use in enhancing humanity’s quality of life. Now is the time to utilize that potential to enhance humanities dreams.

Abstract

Humanity’s ambitious dreams of leaving footprints on far away worlds comes many challenges. Fortunately, with the advances in current technology, these challenges can be conquered from many directions. In-space manufacturing (ISM) has the potential to be one of the technologies which will bring human exploration dreams to life. ISM includes techniques such as 3D printing, recycling, and assembling, chemical and biological process. Due to its many benefits, such as minimal wastage and highly customizable products, a significant focus will be drawn to 3D printing in this report. This technology has proven itself to be fruitful to a variety of Earth applications. Hence, current initiatives are focusing on expanding 3D printing into space, more specifically to space habitats.

This report discusses on the potential of ISM as a solution to enable a self-sustaining space habitat without re-supply requirements. The report is split into two sections. The first section of the report uses the International Space Station (ISS) as an analogue to identify numerous areas where ISM can be and is leveraged during expeditions.

In the second section, a crewed deep space mission is defined as a space habitat with seven crew members beyond the Earth’s GEO ring for a continuous period of three years without re-supply. Since the location and duration of this mission are dissimilar to the ISS, differences in technical and crew requirements of the two space habitats are established. ISM technologies, either developed or in-development, are proposed for each of the requirements. The respective technology readiness level, challenges and risks are also mapped for each proposed technology. Furthermore, the mission is perceived through a financial, political, legal, and ethical lens.

Following the two sections, the report concludes with the added value of ISM and recommendations to any gaps identified between space habitat requirements and technology capabilities.

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Table of Contents INTRODUCTION 1 Motivation 2 Methodology 4 ISS ANALOG 5 1 Internal Failures and External Threats 6 1.1 Internal Failure 6 1.2 External Threats 8 1.2.1 Impact from External Objects 8 1.2.2 Extreme Temperatures 10 1.2.3 Radiation 10 2 Crew Needs 11 2.1 Atmosphere 11 2.2 Water 12 2.3 Food 12 2.4 Crew Health 15 2.5 Clothing 16 3 Additive Manufacturing on ISS 17 3.1 Current Techniques 17 3.2 In-Development Techniques 21 4 Other Manufacturing on ISS 24 Chapter 1 Summary 27 DEEP SPACE CREWED MISSION 28 1 Mission Type 29 2 Human Factors 31 2.1 Critical Crew Needs 32 2.1.1 Requirements 32 2.1.2 Technology 33 2.2 Waste Management 35 2.2.1 Requirements 35 2.2.2 Technology 35

2.3 Medicine 37 2.3.1 Requirements 37 2.3.2 Technology 38 2.4 Medical devices 41 2.4.1 Requirements 41 2.4.2 Technology 41 2.5 Mental Health 45 2.5.1 Requirements 46 2.5.2 Technology 46 2.6 Radiation (Crew) 48 2.6.1 Requirements 48 2.6.2 Technology 50 3 Technical Factors 54 3.1 Radiation 54 3.1.1 Requirements 54 3.1.2 Technology 55 3.2 Communication 56 3.2.1 Requirements 56 3.2.2 Technology 59 4 Spacecraft Parameters 61 4.1 Storage Space 61 4.2 Mass 61 5 TRL Timeline 63 6 Challenges 66 6.1 Design Challenges 66 6.2 Manufacturing Challenges 68 6.3 Qualification and Standardization Challenges 70 7 Risks 72 8 Financial Considerations 79 8.1 Case Study - Plastic Spares 80 9 Political Considerations 84 9.1 Public Private Partnerships 84

9.2 Agencies Grading 84 9.2.1 Big Partners 84 9.2.2 Future Players 87 9.2.3 Recommendations 88 10 Legal Implications 90 10.1 Legal framework 90 10.2 General considerations 90 10.3 Intellectual and Industrial property issues 90 10.3.1 Intellectual property 90 10.3.2 Industrial property law 90 10.3 Goods or services provider? 91 10.3.1 The difference between the two notions 91 10.3.2 Manufacturing in orbit only implies providing goods 91 10.4 3D printing and liability: Tort law 91 10.4.1 Tort law 91 10.4.2 For the crewed mission: Health issues and Tort Law 93 11 Ethics 94 11.1 Ethics and Automation 94 11.2 Mimicking Mother Nature 95 ADDED VALUE 96 RECOMMENDATIONS 98 CONCLUSION 101 REFERENCES 103

List of Figures

Figure 1: Manufacturing methods which are considered as subcategories of ISM in this report. 18 Figure 2: Classification of additive manufacturing techniques 19 Figure 3: Percentage of failed parts and components on the ISS 24 FIgure 4: Estimated ISS maintenance logistics, 2012-2020. Mass estimates are for spare items only 25 Figure 5: Illustration of the damage caused by a hypervelocity impact 26 Figure 6: Sentinel-1 fragment impact in space 26 Figure 7: Multi-layer and twin-layer Whipple shields with debris impacts 27 Figure 8: University of Stuttgart algae bioreactor 31 Figure 9: A customized finger splint 3D printed on the ISS 34 Figure 10: The 3DP Tech Demo; the first 3D Printer in zero gravity 35 Figure 11: A sample of 3D printed parts on the ISS for the astronauts 36 Figure 12: The Additive Manufacturing Facility (AMF) on board of the ISS 38 Figure 13: The Refabricator 39 Figure 14: Shuttle Remote Manipulator System and Mobile Servicing Systems 42 Figure 15: European Robotic Arm 42 Figure 16: Japanese Experimental Module Remote Manipulator System 43 Figure 17: Robonaut 2 onboard ISS with astronaut Steven Swanson 44 Figure 18: Diagram of current ISS and required future habitation systems elements 49 Figure 19: FabRx’s chewable medicines showing different dose sizes 58 Figure 20: Surgical tools, splint, face mask, otoscope and a fitting 60 Figure 21: Examples of patient specific 3D printed consumables 61 Figure 22: Heart model by Stratasys 62 Figure 23: 3D printed hip joint replacement tool by GE 63 Figure 24: Metal 3D printed automatic suturing tool from Suture 63 Figure 25: Effectiveness of different radiation protection materials vs. launch mass 69 Figure 26: Simple hydrogen shielding design 70 Figure 27: Solar Cell Power Loss vs Radiation (700 km altitude, 30° inclination) 73 Figure 28: NASA Deep Space Network Capabilities 76 Figure 29: Relationship between Performance and Antenna Size 76 Figure 30: Archinaut Dilo Spacecraft Attaching its Reflectors 78 Figure 31: Mass savings from AM using earth based and ISRU feedstock 79 Figure 32: An explanation of TRL levels 82 Figure 33: Risk matrix associated with proposed ISM technologies 97 Figure 34: NASA’s forecasted available budget and costs of human spaceflight program 102 Figure 35: NASA Design Review Architecture 5.0 for Human Landing on Mars 103

List of Tables

Table 1: List of Phase I products 34 Table 2: List of Phase II products 37 Table 3: Printing capacity of the AMF 38 Table 4: Examples of AMF products printed on the ISS 38 Table 5: Systems in Phase I and II of NASA’s ISM technology development efforts 40 Table 6: Closed loop efficiencies for Oxygen, Food and Water for a 3-year mission of 7 members 50 Table 7: Mass savings with increased recycling rates 50 Table 8: A bioregenerative HPGF’s impact on S/C food production and atmospheric recycling 51 Table 9: Breakdown of ISS waste for three people per year 53 Table 10: Comparison of aerobic and anaerobic waste treatment 54 Table 11: Examples of pharmaceutical formulations that were developed by 3DP technology 56 Table 12: Printing technologies for medical devices 60 Table 13: Career astronaut limits for males and females at varying age 67 Table 14: Mission specific radiation doses 67 Table 15: Trade-off to provide advantages and disadvantages of various shielding methods 70 Table 16: Recommendations for radiation shielding in spacecraft 71 Table 17: Free-Space Path Loss at Various Frequencies 75 Table 18: Mass of spares and reduction by using AM on a twenty-six month deep space mission 79 Table 19: Technology Readiness Levels of discussed ISM technologies 83 Table 20: SWOT analysis of 3D printing 84 Table 21: ISM Design Challenges 85 Table 22: ISM Manufacturing Challenges 87 Table 23: ISM Qualification and Standardization Challenges 89 Table 24: Risks, Ratings, and Mitigation strategies 90 Table 25: Information regarding ISS Spares 100 Table 26: Mass and Costs of Plastic Spares Required on a Spacecraft without ISM Capabilities 100 Table 27: Mass and Costs of Plastic Spares Required on a Spacecraft with ISM Capabilities 100 Table 28: Mass and Costs of Plastic ISM Equipment Required on a Spacecraft 101 Table 29: Recommendations for working with agencies 106

List of Acronyms

3DP 3D Printing ABS Acrylonitrile butadiene styrene AI Artificial Intelligence ALSS Adaptive Laser Sintering System AM Additive Manufacturing AMF Additive Manufacturing Facility AMSC Additive Manufacturing Standardization Collaborative ANSI American National Standards Institute ASA Acrylic Styrene Acrylonitrile / Aminosaicylic Acid BEAM Bigelow Expandable Activity Module BLEO Beyond Low Earth Orbit BPS Biomass Production System CAD Computer-Aided Design CAS Chinese Academy of Sciences CCPA Central Committee of the Communist Party of China CMSE China Manned Space Program CNSA Chinese National Space Agency COPUOS United Nations Committee on the Peaceful Uses of Outer Space CQ Crew Quarters CRG Cornerstone Research Group CRISSP Customizable Recyclable International Space Station Packaging CSA Canadian Space Agency CSU Center for Space Utilization DLP Direct-Light Processing / Digital Light Processing DSOC Deep Space Optical Communications DMLM Direct Metal Laser Melting DRA Design Reference Architecture EBF3 Electron Beam Freeform Fabrication EBM Electron Beam Melting ECEEE European Council for an Energy-Efficient Economy ECLS Environmental Control and Life Support System EEC European Economic Community EEG Electroencephalogram EF Exposed Facility EMCS European Modular Cultivation System ERA European Robotic Arm ERASMUS European community Action Scheme for the Mobility of University Students ESA European Space Agency ESPRIT European System Providing Refueling, Infrastructure and Telecommunications

III

EU European Union EVA Extra-Vehicular Activity EXPRESS Expedite the PRocessing of Experiments to Space Station FabLab Fabrication Laboratory FDM Fused Deposition Modeling FDA Food and Drug Administration FFF Fused Filament Fabrications FIT Factory in a Tool FSPL Free-Space Path Loss GCR Galactic Cosmic Radiation GE General Electric GEO Geosynchronous Equatorial Orbit HDPE High-Density Polyethylene HEOMD Human Exploration Operations Mission Directorate HERA Hybrid Electronic Radiation Assessor HMC Heat-Melt Compactor HPGF Hydroponic Plant Growth Facility ISM In-Space Manufacturing ISRO Indian Space Research Organization ISS International Space Station ISU International Space University IVA Intra-Vehicular Activity IVTEPC Intra-Vehicular Tissue Equivalent Proportional Counter JAXA Japanese Aerospace Exploration Agency JEMRMS Japanese Experimental Module Remote Manipulator System LaRC Langley Research Center LED Light-Emitting Diode LEO Low-Earth Orbit LH2 Liquid Hydrogen LMD Fused Metal Deposition LOX Liquid Oxygen MAMBA Metal Advanced Manufacturing Bot-Assisted Assembly MBS Mobile Base System MLI Multi-Layer Insulation MLM Multi-purpose Laboratory Module MPCV Multi-Purpose Crew Vehicle MPLM Multi-Purpose Logistics Module MR Manufacturing Readiness Level MSS Mobile Servicing System NASA National Aeronautics and Space Administration NextSTEP Next Space Technologies for Exploration Partnerships OGS Original Groove System

PA Polyamide PC Polycarbonate PEI Polyetherimide PEU Plant Experiment Unit PGBA Plant Generic Bioprocessing Apparatus PGF Plant Growth Facility PGU Plant Growth Unit PPP Public-Private Partnership PPSF Polyphenylsulfone R2 Robonaut 2 R&D Research and Development REM Radiation Enclosure Monitor RFID Radio-Frequency Identification SATCOM Satellite Communications SBIR Small Business Innovative Research S/C Spacecraft SIMPLE Sintered Inductive Metal Printer with Laser Exposure SLA Stereolithography SLM Selective Laser Melting SLS Selective Laser Sintering SPDM Special Purpose Dexterous Manipulator SPHERES Synchronized Position Hold Engage Reorient Experimental Satellites SRMS Shuttle Remote Manipulator System SSA Space Situational Awareness SEE Single Event Effect SMM Satellite Manufacturing Machine SpaceX Space Exploration Technologies SSRMS Space Station Remote Manipulator System STEPS Software and Tools for Electronics Printing in Space STTR Small Business Technology Transfer SWOT Strengths Weaknesses, Opportunities, Strengths TEPC Tissue Equivalent Proportional Counter TRL Technology Readiness Level TUI Tethers Unlimited UAM Ultrasonic Additive Manufacturing UM Nodal Module UNOOSA United Nations Office for Outer Space Affairs US United States VEGGIE Vegetable Production System

V Introduction

INTRODUCTION

Space has always been seen as a domain of exploration and discovery. The mystery and unknown quality of space has led to speculations and tales of fantasy. Coupled with an infinite and elusive nature, religions and mythologies have looked to the heavens for their inspiration for thousands of years. From launching the first object into orbit in 1957 to a human-made object reaching over 145 astronomical units away from Earth, humans have always been intrigued by the curiosities of space and have fed their curious minds through technology. Technology provides the capability of expanding upon humanity’s current accomplishments in the space industry. Specifically, implementing manufacturing techniques (a process which outputs a product from an input) in-space has the potential to revolutionize the way humans use and explore the barriers of space.

The following report will closely follow the definitions established by Skomorohov, Hein, and Welch (2016) and Trujillo, et al. (2017) when defining in-space manufacturing (ISM). Skomorohov, Hein, and Welch (2016), define ISM as “any endeavor which takes place outside of Earth’s atmosphere and which performs any of the three activities: fabrication, assembly, and integration”. Trujillo, et al. (2017) define ISM as “an umbrella term for a variety of technologies, processes and architectures which deliver a desired component or system to a spacecraft outside of the traditional Earth-launch paradigm”.

Therefore, this report will consider the ISM subcategories as illustrated in Figure 1. However, 3D printing, also known as additive manufacturing (AM), will constitute the major focus of the report due to the recent rise in interest of 3D printing in-space. Furthermore, recycling, assembly, biological, and chemical manufacturing processes will be addressed in the report.

Figure 1: Manufacturing methods which are considered as subcategories of ISM in this report.

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Introduction

Current initiatives have been focused on developing traditional manufacturing by pushing it towards in- space 3D printing. Common 3D printing techniques begin with the production of a Computer Aided Design (CAD) model or part. Afterwards, the 3D printer reads in data from the CAD file and lays down or adds successive layers of liquid, powder, sheet material or other material, in a layer-upon-layer fashion to fabricate a 3D object (AmazingAM, 2018).

These techniques are expected to play a significant role in the future of manufacturing due to the numerous benefits as listed by Ghosh (2015): highly customizable, minimal wastage of raw materials, lighter, and more optimized parts. Researchers are looking into enhancing current printing technologies and expanding its borders. Terrestrial applications of 3D printing have been very successful and there is a new focus to reap the benefits this technology in space. Figure 2 describes the current additive manufacturing techniques available on Earth. Most of the techniques listed in Figure 2 cannot yet be implemented in space due to a microgravity environment. However, researchers are currently focusing on ways to tackle this challenge.

Figure 2: Classification of additive manufacturing techniques (Joshi and Sheikh, 2015).

Motivation

Although there are many reasons to pursue ISM, the main rationales are outlined by Johnston, et al. (2014):

Rationale 1 - Known and Predicted Repair The normal wear and tear of parts on the ISS require stockpiles of spares and additional components to be readily available for timely replacement. These stockpiles can occupy large volumes on the ISS which can be vacated for other needs such as crew recreational quarters. These large storage volumes will be reduced with the introduction of additive manufacturing. Any required component can be printed and

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Introduction there will be no need to store components which may or may not be used; instead compact filament, powder or liquid for the printers will be stored.

Rationale 2 - Known Production and Assembly Current launching techniques generate intense vibrations which can be detrimental to delicate cargo. There are also structural and geometric constraints imposed on payloads due to the limited space. These issues can be by-passed through manufacturing of delicate or large components in space. Furthermore, printing techniques on the ISS will mitigate the significant cost of launching all equipment possibly required to the ISS as astronauts on the space station have long been reliant on launches from Earth to bring spare parts.

Rationale 3 - Unknown Repair and Replacement Due to parts and components failing spontaneously, either the stockpiles of common failing parts are used or the crew has to wait for a resupply mission. In the case of waiting for a resupply mission, the disturbance to flight experiments, crucial operational equipment failure, or even a medical emergency can be detrimental to the success of a mission. Such critical situations can be prevented by the 3D printing techniques available on a space habitat for quick responses to any unforeseen circumstances. Parts that are unlikely to fail, but do, may not have replacements stored. The ability to produce unique parts on demand enables these unforeseeable failures to be easily resolved. With 3D printing these replacement parts can be produced on station, thus removing the need for storage of spare components with a low risk of failure.

In the near future, ISM may become the primary platform for producing numerous goods as these methods may be more economical and efficient. As stated by Jason Crusan, director of NASA's Advanced Exploration Systems Division at NASA Headquarters in Washington, "Additive manufacturing with 3D printers will allow space crews to be less reliant on supply missions from Earth and lead to sustainable, self-reliant exploration missions where resupply is difficult and costly. The space station provides the optimal place to perfect this technology in microgravity" (Hubscher and Mohon, 2014). Furthermore, ISM has the potential to positively affect human spaceflight operations by reducing existing logistics requirements for the ISS and future long-duration human space missions.

This report will serve to provide knowledge in regards to the possibility of exploiting ISM to bring the dreams of deep space crewed exploration to life. The role which current technology can play to support ISM and subsequently enable crewed deep space exploration will be discussed in detail. This transfer of knowledge from the authors to the readers will be accomplished through a structured approach.

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Introduction

Methodology

Prior to this report, an extensive literature review was performed to understand the current terrestrial 3D printing technologies and their potential applications in the space sector. ISM techniques currently in development and utilized on the ISS have also been reviewed and analyzed to provide insight into the potential of expanding these techniques to deep space crewed missions. For the purpose of this report, the term deep space applies to any distance beyond the geosynchronous equatorial orbit (GEO).

As of now, many additive manufacturing projects have been carried out successfully on the ISS. Although these products are currently on a small scale, they are a stepping stone towards printing larger and more complex structures in space. Along with this first step come many questions about the potential of 3D printing in space and what breakthroughs these technologies will bring into fruition. Additionally, other ISM technologies such as assembly, recycling, biological and chemical processes have enabled the ISS to come into existence and sustain a crew of six crew members at a time. Hence, this report has been divided into two chapters to assess the potential of ISM within space habitats: 1) ISS Analogue and 2) Deep Space Crewed Mission.

Chapter one of the report provides a foundation for further study, exploring the current state and projected development of ISM aboard the ISS. By analyzing common equipment failures on the ISS along with the associated risks, the role of 3D printing in mitigating those risks is assessed. Furthermore, analyzing additional requirements for the ISS due to human presence can open new horizons for the potential of 3D printing. Therefore, it is important to discuss current technologies, developing technologies and other manufacturing methods to be deployed in space and on the ISS.

The second chapter of the report builds onto the foundation presented in the first chapter and expands ISM to crewed missions in deep space. The mission type and the respective requirements are defined and initial assumptions are established to provide consistency and ease of utilizing the ISS as a reference. Afterwards, the difference in requirements between the ISS and the deep space mission are outlined. These requirements are classified into: (i) human factors and (ii) technical factors. Manufacturing technologies, specifically 3D printing, which are currently developed or in-development for Earth or space application are proposed as potential solutions for each of the aforementioned requirements. The feasibility analysis of the proposed technologies will entail: (i) technology readiness level (TRL), (ii) risks, and (iii) challenges. Once the technical aspects of the missions are defined and discussed, the mission will be analyzed from a political, legal, ethical, and financial perspective. This perspective will shed light onto any additional challenges with using ISM to enable a crewed deep space mission.

After the two aforementioned chapters, the report will examine the added value of utilizing ISM. Lastly, recommendations in regards to filling any gaps between crewed mission requirements and the current technology will be discussed.

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CHAPTER ONE

ISS ANALOG

Chapter One: ISS Analogue

1 Internal Failures and External Threats

Like any system, the ISS is prone to failures. These failures can stem from hardware failures of individual components or within subsystems. The crew on the ISS is responsible for performing duties related to replacing and repairing damaged components. In addition to internal failures, there are also external threats originating from the harsh environment of space. These external threats can impact the normal operations of the station. With advances in ISM techniques, the logistical burden of replacing or repairing components can be reduced while the external threats are mitigated.

1.1 Internal Failure The ISS witnesses numerous failures in hardware across different components as illustrated in Figure 3. Those failures can stem from components that have reached their end-of-life due to wear and tear or unexpected failures. Components with a limited lifetime need to be replaced and repaired on a daily basis, namely igniter tips, overhead lights, and various waste filters in the regenerative life support system. Some components may be utilized on a daily basis or some may be delicate which makes them more prone to failure than others. The most common failures ordered by highest to lowest failure rate are: (i) electrical and electronic components, (ii) plastic and composites, (iii) mechanical metal parts, and (iv) ceramics and glass. Unfortunately, with current technology, approximately 18% of hardware failures are not candidates for additive manufacturing or repair (National Research Council, 2014a).

In addition to damage and failure, the ISS crew must contend with lost or misplaced tools and unattached components due to the ventilation system and other microforces. Therefore, there is a need for multiple spare components to replace lost or damaged tools. 3D printing can help reduce the demand for spare components by introducing on-demand production of tools and parts. Current 3D printing technologies on the ISS and their catalog of products are further discussed later in this chapter in Sections 3.1, 3.2, and 4.

Figure 3: Percentage of failed parts and components on the ISS (Adapted from the National Research Council, 2014a).

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Chapter One: ISS Analogue

Currently, the ISS relies upon a resupply mission every three months which carries crucial cargo. In each resupply, the cargo encompasses various substances ranging from sustenance for crew members to replacement parts and spares for equipment susceptible to failure (Owens and de Weck, 2016). The mass of resupply that the ISS requires is displayed in Figure 4. As shown, there are 13,170 kg of spares stored on the ISS for the estimated failure mass of 450 kg annually. Unfortunately, nearly 95% of the 31,170 kg of spares are never utilized, thus requiring an unnecessary high financial investment to respond to maintenance demands (Owens and de Weck, 2016). Furthermore, the volume and mass detained for storage uses can be drastically reduced with ISM. Raw material required for 3D printing is commonly stored in compact geometries, which can help save volume. The need to store an abundant amount of spares will be nonessential since a component can be printed when it is required. Hence, the endurance of ISS, time without resupply, will be increased with the introduction of ISM.

FIgure 4: Estimated ISS maintenance logistics for 2012-2020, including ground storage, upmass, on-orbit storage, and expected utilization. Mass estimates are for mass of spare items only; does not include packaging and carrier mass (Owens and de Weck, 2016).

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Chapter One: ISS Analogue

1.2 External Threats The orbital altitude of the ISS lies in a harsh environment of vacuum, microgravity, extremes of temperature, meteoroids, space debris, ionospheric plasma, and ultraviolet and ionizing radiation (Thirsk, et al., 2009). Given the environment that the ISS operates in, an assessment of environmental threats and mitigation strategies is necessary. The failures and dangers associated with impact from external objects, thermal control, and radiation will be discussed with respect to the potential of ISM in these areas.

1.2.1 Impact from External Objects According to ESA, there are more than 29,000 objects larger than 10 cm that can heavily damage a spacecraft. The impact of a 1 kg piece of debris has the same impact as a 35,000 kg tractor-trailer travelling at 190 km/hr (Thirsk, et al., 2009). Figure 5 displays a 12 mm aluminum sphere travelling at a velocity of 6.8 km/s into an aluminum block. This illustrates the extent of an impact from a hypervelocity space object, either a small meteoroid or debris, on the ISS and more generally on a spacecraft. Any collision of a 10 cm object with a spacecraft will most likely cause a catastrophic failure (ESA, 2013). Apart from physical damage to the ISS’s hull, damage to solar panels can occur, leading to power outages. A collision between a piece of fragment debris and Sentinel-1 solar panels is shown in Figure 6.

Figure 5: Illustration of the damage caused by a hypervelocity impact (ESA, 2013).

Figure 6: Sentinel-1 fragment impact in space (ESA, 2013).

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Chapter One: ISS Analogue

The probability of a meteoroid or micrometeoroid impact with the ISS has increased when compared to the probability during the beginning of ISS operations (Akahoshia, et al., 2008). NASA has estimated the probability of a micrometeoroid debris strike causing depressurization of the station, fire, or toxic release of ammonia is 1 in 120, 1 in 46,000, and 1 in 5.6 million, respectively. In addition, the risk of a micrometeoroid penetrating the station and causing a catastrophic failure (a condition where disabling or fatal injury occurs to personnel or loss of the ISS occurs) is 33 percent and 6 percent, respectively (NASA Inspector General, 2018). Therefore, Space Situational Awareness (SSA) detects and monitors space objects, including debris, in Earth’s orbit and determines their position and velocity (Elias, et al., 2014). Currently, the hazard of potential debris collisions with the ISS is minimized by: (i) shielding critical elements of the ISS to protect them from impacts with the meteoroids and debris (<10 cm), (ii) performing collision avoidance maneuvers for debris larger than 10 cm, and (iii) implementing design features and operational procedures (National Research Council, 1997).

Current shielding techniques use outer shell aluminum and Whipple shields as illustrated in Figure 7. Whipple shields usually include layers of Kevlar or Nextel which utilize their high strengths to break the projectile into smaller and lower energy particles (Christiansen, et al., 1995). It is possible to replace the damaged shields. By utilizing ISM, the replacement shields may be 3D printed in space to avoid launching constraints imposed on cargo payloads. Furthermore, shielding plates that have been exposed to high impact frequencies can be removed and recycled (Section 3.2 of Chapter 1 further describes metal recycling capabilities on the ISS using MAMBA from Tethers Unlimited). Thereon, the recycled material can then be utilized as raw material for the production of replacement shields. This process is currently being utilized terrestrially; Kevlar is being recycled by companies such as Ballistic Recycling Intl (Anon, 2019). However, such a recycling technology has yet to be developed for the ISS and increase ISM capabilities. Nevertheless, the assembly of Whipple shields on the exterior of the ISS will require robotic assembly arms which are discussed in further detail in Section 4 of this chapter.

Figure 7: Multi-layer and twin-layer Whipple shields with debris impacts (NASA, 2013).

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Chapter One: ISS Analogue

1.2.2 Extreme Temperatures The ISS is on the sunlit side of the Earth for 45 continuous minutes which exposes it to temperatures in excess of 100°C. While in Earth’s shadow for an equivalent time, the ISS can experience temperatures below -100°C (Thirsk, et al., 2009). To protect the crew and system components, four methods are used to control the thermal system: insulation, surface coatings, heaters, and heat pipes (NASA, 2015a). Without proper thermal control, various ISS systems can fail due to environmental factors such as extreme cooling and heating.

Thermal threats can be further mitigated through the use of ISM. During emergency situations, such as damage to thermal systems, extra insulation may be 3D printed to maintain a temperature which allows subsystems to operate at full efficiency and effectiveness. In addition, heat pipes and heat exchangers are currently 3D printed on Earth using laser powder bed fusion (Saunders, 2018). Such a technology can be leveraged in space for emergency situations when excess thermal energy needs to be disposed of. Furthermore, spare components can also be printed from recycled parts for heaters and heat pipes if there is damage to the current components.

1.2.3 Radiation The ISS orbits above the Earth’s atmosphere exposing it to radiation sources from galactic cosmic rays (energetic particles from outside the solar system), particles trapped in the Earth’s magnetic field (the Van Allen Belts), and solar energetic particle events (solar flares) (Thirsk, et al., 2009). Both ionizing and non- ionizing radiation can cause long-term health effects, equipment failures, and malfunctions. Galactic cosmic rays are high-energy and almost impossible to fully shield against, however, water shelters and polyethylene are currently used as radiation shields for spaceflight and orbital habitats. In addition, a deployable structure to protect the ISS from radiation shielding is possible but due to the size and mass constraints posed by some launching capabilities, these large and heavy structures are impractical (International Space University Space Studies Program, 1998). Hence, by 3D printing these deployable structures in space, these launch constraints can be bypassed.

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2 Crew Needs

Due to the lack of autonomy on the ISS, there is a need for a continuous human presence. In order to ensure the health, safety, and welfare of the crew in the hostile environment of space, the space station must be equipped with numerous life support systems. Since each ISS expedition lasts a duration of approximately six months with three to six crew members, there is a need for a habitable atmosphere; a supply of water, food, and clothing; and safety considerations for the crew. The following section will further discuss these requirements in detail along with their respective ISM techniques (recycling, chemical process, and/or biological process).

2.1 Atmosphere The oxygen requirements of an astronaut on the ISS is 0.83 kg per day (303 kg per year) (NASA, 2015c). The requirement is predominantly supplied by electrolysis. This chemical process utilizes electricity from the solar panels to split water into hydrogen and oxygen molecules. Thereafter, the hydrogen molecules are vented into space. Excess hydrogen molecules can be used as a source of fuel or propellant in the future. This could be an efficient way to use all products and recycle. However, large quantities of stored hydrogen around the station do expose humans to the potential risk of an explosion (Barry, 2000).

In addition to oxygen requirements, the atmosphere within the ISS must be free of gases in concentrations which pose a danger to crew health. Humans produce gases such as ammonia, carbon monoxide and methane via urine, respiration, and digestion, respectively. These gases are harmful in significant concentrations and hence they are filtered from the ISS air via charcoal filters. Furthermore, since October 2010 the ISS features a Sabatier process, which allows carbon dioxide to catalytically react with hydrogen to create drinkable water and methane (NASA, 2011). Any excess carbon dioxide from the process, exhaled by humans, is vented into space. In addition, two backup responses to oxygen demands are implemented on the ISS: (i) large tanks of compressed air are mounted outside of the airlock capsule, and (ii) storage of metal canisters packed with perchlorate, which release oxygen when they are burnt (Barry, 2000).

Although the current technique to maintain the atmosphere within the ISS is through a chemical recycling process, several technological upgrades are required to fully close the loop. The current systems on the ISS have a 42 percent oxygen recovery rate which is not satisfactory (NASA Inspector General, 2018). Hence, due to the low efficiency, resupply missions of oxygen are required to fill the gap in oxygen production. By improving the chemical recycling process, a higher recovery rate of oxygen can eliminate resupply requirements. Furthermore, some components of the environmental control and life support system have an average lifetime of less than six months (NASA Inspector General, 2018). Therefore, subsystems critical to the crew are dependent on storage of spares or resupply missions. An error in calculations or spontaneous failure of a component can be life threatening since a resupply mission only occurs every three months. Fortunately, these risks can be minimized with the introduction of 3D printing onboard allowing a crucial component to be produced instantaneously.

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2.2 Water In order to create a habitable environment for the astronauts on the ISS, abundant amounts of water must be accessible. Water is required for both metabolic and hygienic purposes. On the ISS, an astronaut requires 2.59 kg and 25.27 kg of water daily for consumption and hygiene, respectively. These values equate to a requirement of approximately 10,790 kg of water per year, per astronaut, to sustain day-today operations (Jones, 2010).

The current method of producing water on the ISS is through recycling from atmospheric conditions, waste water, H2-O2 fuel cells, CO2 reduction, and condensation from equipment. The waste water which is collected has to be filtered prior to usage. The waste water passes through three steps before it is purified: (i) a filter which removes particles and debris, (ii) a multi-filtration beds which remove organic and inorganic impurities, and (iii) a catalytic oxidation reactor which removes volatile organic compounds and eliminates bacteria and viruses (Barry and Phillips, 2000). In addition, water purification can be also be achieved by bio-regenerative systems like plants. Plants have the ability to purify waste or partially processed water by utilizing the nutrients in the waste water and perspiring water vapor into the atmosphere (Lane and Schoeller, 2000). This topic will be expanded upon in Sections 2.1 and 2.2 of Chapter 2.

The current production system runs at 90 percent efficiency which leads to the loss of approximately three to six tonnes of water per year that needs to be resupplied (Jones, 2010). It is important to note this figure is highly dependent on crew size hence the large variability. The water is lost from, but not limited to, production of unusable brine, consumption from generating oxygen, leaks in the airlocks, and leaching by

CO2 removal systems (Barry and Phillips, 2000). It is important to increase the efficiency of ISM of water on the ISS and close the loop. Subsequently, the resupply requirements will be reduced and the endurance of the ISS will be increased.

2.3 Food The prior sections discussed two out of the three essential needs for humans to sustain life. This section is going to focus on the third essential need, food. According to NASA, the food requirement for an astronaut on the ISS is 2 kg per day (NASA, 2007). Over a period of one year, considering a crew size of six, this requirement measures to 4,380 kg. Currently, this mass of food is being fulfilled solely by resupply missions.

As previously defined in the introduction, ISM encompasses biological processes such as in-space food production. This process currently at the experimental stage. Stutte, et al. (2011) identified two important objectives that must be achieved by any in-space food production system: (i) support growth from start to finish and (ii) retain water, media, and biological material without contaminating the spacecraft. Furthermore, several food products have been identified as candidates for production in microgravity: agricultural products, microbiological products, chemical synthesis products, animal products, and waste recycling products (Eckart, 1994).

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The sections below discuss the various edible products which have been manufactured using experimental in-space food production technologies. The constraints and difficulties associated with the use of each technology have also been laid out.

Algae Algae have been researched extensively in the early 1950s and 1960s by the United States (US) Military. The reason algae were selected is due to its high photosynthetic efficiency and their ability to grow in small spaces. In addition to these benefits, algae is an effective atmospheric regenerator capable of recycling CO2 to O2. However, the downside of algae is the requirement to process them prior to ingestion. The significant nucleic acids and indigestible cell wall components present in algae makes them difficult to eat unprocessed (Lane and Schoeller, 2000).

Recently, the University of Stuttgart is undertaking research on Chlorella vulgaris algae, with an aim to send an experiment to the ISS. The experiment is to test a hybrid life support system that provides food production capabilities and atmospheric recycling for crewed missions. Preliminary research has estimated that 30 percent of human nutrition needs could be filled with algae bioreactor production in space (Dancer, 2017). Figure 8 displays the algae bioreactor developed by the University of Stuttgart.

Figure 8: University of Stuttgart algae bioreactor (Dancer, 2017).

Microbes Microbes are organisms which range from harmful and beneficial bacteria, viruses, yeasts, protozoans, and fungi. While most microbes are considered to be sources of biological contamination or useful recycling “factories” of biological material, some microbes are also considered as possible food sources for space activities. For example, many species of fungi are edible and are regularly farmed in controlled conditions. Microbes do pose specific challenges due to their nature of airborne spreading, which can become especially complicated in microgravity (Eckart, 1996).

Plants This section is adapted from Lane and Schoeller’s (2000) publication on bioregenerative life support for planetary exploration (pre-ISS). Since the early 1950s, the idea to leverage a plants’ photosynthesis ability for dual uses has been proposed. From one side, plants can provide breathable oxygen by removing

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Chapter One: ISS Analogue carbon dioxide while from the other side, plants can create organic compounds that are used as sources of food in space. Leveraging a varied diet of plants, humans’ nutritional needs can be addressed. It is suggested that leafy and salad type crops would be favored to supply adequate calcium levels as seeds are low on calcium levels. Plants for space travel are selected based on their yield to growth area ratio, amenability to controlled environments, and low processing requirements. After many closed-loop tests with humans, wheat, cabbage, and broccoli are the top three recommended crops, with wheat being tested previously aboard the Russian Mir Space Station. An optimal crop mix is essential to provide crew members with the daily nutritional requirements in terms of carbohydrates, proteins, and lipids. Some plants produce higher yields in brighter lighting conditions, and as such, illumination aspects should also be considered for in-space food production needs, with some plants requiring dark cycles, while other plants being tolerant to constant illumination.

Plants have been grown in the space environment for over 40 years, with the first plant experiments performed on Salyut 1 during the Oasis 1 experiment in 1971. Since Oasis 1, there have over 20 different plant experiments on board a spacecraft with over 40 different plant species experimented upon (Zabel, et al., 2016).

As of 2013, the ISS has been used to test VEGGIE, a deployable plant growth unit that provides the crew with fresh food. While official data from the experiment has not been released as of late 2018 (NASA, 2019a), VEGGIE is a testbed not only for nutritional and food production, but also for psychological and radiation protection methods for long duration flights. Having something green from Earth, something meaningful to do during a mission and the anti-oxidative benefits of fresh plants are all bound into VEGGIE’s research (NASA, 2015b).

It has been calculated that 10-20 m² of continuously planted area could meet one single astronaut’s O2 needs, while an area of about 30-50 m² would be needed for adequate food production. In addition to food production and atmospheric recycling, plants also perform wastewater management, with waste water fed to plants, and transpiration from them providing clean water as collectable moisture (Lane and Schoeller, 2000).

Animals Silkworm moth larvae show strong potential for use as an animal protein source for astronauts during long-term deep space exploration. Silkworm living on mulberry leaves have the following benefits for use in space: high protein content, reasonable nutrient compositions and ample contents, a short lifespan, easy breeding method, small growth room, little odor, and wastewater produced (Yang, et al., 2009).

Brinckmann and Schiller (2002) designed concepts for experiments with insects and aquatic organisms such as rotifers, nematodes, and other small aquatic animals (sea urchin larvae, tadpoles, fish youngsters) using two ESA facilities which will be available for animal research and other biological experiments on the ISS: the European Modular Cultivation System (EMCS) in the US Lab “Destiny” and BIOLAB in the European “Columbus” Laboratory.

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Furthermore, other animals have been considered as a potential source of nutrition for long term missions. Due to long and complex life cycles of most animals, animals with short life cycles have been proposed as the most suitable. This could include animals like rapidly reproducing fish species (Eckart, 1994). As an example, Japanese rice fish, medaka, has been used as a research animal aboard ISS. Research has proven that medaka are relatively unaffected by microgravity and could live full life cycles aboard a spacecraft with only minor stress related issues (Ijiri, 2003; Murata, et al., 2015). Animals as a food source will be further considered in Section 2.1.2 of Chapter 2.

2.4 Crew Health The presence of equipment for crew health holds a significant value on the ISS. As astronauts are carrying out their expedition, return to Earth is not always possible in a short time. Hence, stockpiles of medical supplies are required. While an analysis of the likelihood of injuries during a space mission could identify the crucial medical supplies required, this is not without issue. Unforeseen circumstances may trigger the need for non-stocked items, multiple injuries may occur simultaneously, or the use of generic devices may cause significant hindrance to the working requirements of the crew. Furthermore, a minor trauma could cause fractures abetted by bone demineralization due to microgravity. In any emergency situation, crew members must be able to respond immediately.

Currently, medical devices and drugs are available in stockpiles which are resupplied to the ISS via cargo missions. With the improvements in ISM, any risks associated with the aforementioned situations can be mitigated. The sections below outline the current and developing ISM technologies implemented in the ISS to provide astronauts with instantaneous access to critical medical devices and drugs.

Medical Devices Medical devices such as splints can take up valuable volume and mass but may never be needed. On- demand patient specific medical supplies can provide astronauts with more effective personalized products. A company, 3D4MD, has developed CAD models for medical supplies which can be uploaded and printed on the ISS using Made in Space’s Additive Manufacturing Facility (further discussed in Section 3.1 of Chapter 1). This company aims to leverage 3D printing systems to address global healthcare issues on Earth as well as astronauts’ medical requirements (3D4MD, 2019). Their medical team designed a digital model of a custom-fitted finger splint as shown in Figure 9. With an on-board 3D printer, astronauts can now have basic personalized medical supplies during space mission (Davies, 2017).

Figure 9: A customized finger splint 3D printed on the ISS (Davies, 2017).

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Drugs The medical supply needs can be partially fulfilled by producing antibiotics through microbial processes. As an example, actinomycin D has been produced onboard of the ISS during a 72- day experiment with a bacteria species, Streptomyces plicatus. Actinomycin D is ingested to prevent bacterial and tumorous activity (Koba and Konopa, 2005). It was observed that microgravity increased the rate of early-stage production of antibiotics relative to terrestrial antibiotic production (Benoit, et al., 2006). Antibiotic production can prove valuable in confined spaces where infections may be unavoidable and hygiene conditions may degrade rapidly in comparison to an open environment. Other manufacturing technologies used on Earth to print personalized patient-specific drugs are discussed in Section 2.3 of Chapter 2.

2.5 Clothing Clothing in space is currently a challenge. Designing clothes for use in microgravity has to take into consideration safety, moisture absorption, and freedom of movement. Hence, the design of clothing has to be carefully considered (Yamashita and Wheeler, 2014). Furthermore, the size of clothing typically worn by a crew member on Earth will increase in space due to the elongation of their spine.

For a crew of six, over 400 kg of clothing is supplied to the ISS per year (NASA, 2019f). As there is no laundry washing facility on the ISS, the crew receives new sets of clothing that are changed periodically (either daily or weekly) (Stine, 1997; Yamashita and Wheeler, 2014). Dirty clothes are currently jettisoned from the ISS along with other solid wastes such as trash (Anderson, Barta and Lange, 2015). With the implementation of ISM, clothes can be 3D printed. Combined with textile recycling capabilities, the cost of launching a resupply of clothes can be drastically reduced along with the storage volume requirements. Such technologies can also provide astronauts with personalized clothes that are adapted to their changing bodies affected by the long-duration microgravity environment.

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3 Additive Manufacturing on ISS

This section of the report will focus on discussing further in detail the current and in-development 3D printing technologies for the ISS. In-space 3D printing is considered as an infant technology with its first initiatives in 2014. However, space agencies have placed an emphasis to mature such technologies because of their ability to reduce spare part mass and resupply missions. This section will go into more detail about specific products and capabilities of three additive manufacturing technologies on the ISS. The section will conclude with NASA and ESA initiatives on additive manufacturing.

3.1 Current Techniques Demo 3D Printer - 2014 To understand the necessity to mature in-space 3D printing technologies, NASA partnered with Made In Space to develop 3D printing techniques which would efficiently and effectively print in microgravity. In 2014, after extensive testing on a number of parabolic flights the previous year, the 3D Printing (3DP) Tech Demo was built and launched to the ISS. The printer is displayed in Figure 10 (Made In Space, 2017).

The material used for the printer was Acrylonitrile Butadiene Styrene (ABS) plastic, chosen for its strength, low toxicity, and ease of use (Prater, et al., 2016). Using forced convection to drive the substrate and replace gravity, the printer was able to print small parts and tools shown in Figure 11 via Fused Deposition Modeling (FDM). This demonstrated the possibility to further additive manufacturing capabilities in microgravity including recycling of waste substrate (Made In Space, 2017).

Figure 10: The 3DP Tech Demo; the first 3D Printer in zero gravity (Made in Space, 2014).

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Figure 11: A sample of 3D printed parts on the ISS for the astronauts (made-in-space-3D-printed-objects, n.d. and World’s-First-Tool-Made-In-Space-Using-3D-Printing-1, n.d.).

To date, the 3DP has printed over 50 parts (Bean, et al., 2016). The printer was used as a proof of concept to print two phases worth of mechanical test coupons as seen in Table 1 and 2.

Phase I printed 22 various parts and these parts were sent down to Earth for analytical testing (Bean, et al., 2016). The parts were found to have superior tensile strength when compared to their terrestrial counterparts but inferior compressive strength (Bean, et al., 2016). The experimenters at NASA did not know the cause of the variance but believed that the extruder tip was too close to the build tray which was remedied during the phase II experiments (Bean, et al., 2016).

Phase II was conducted in 2016 and 34 additional parts were printed. These prints were again sent back to NASA for analysis on Earth and found that the specimens from phase I and phase II showed no statistical differences. The source of error was deemed to be a multitude of variables that are uncontrollable and inherent to the different manufacturing environments (Prater, Werkheiser and Ledbetter, 2018). However, NASA did conclude that microgravity was not the cause of these variances and considered their proof of concept complete. Tables 1 and 2 lists the products printed during Phase I and Phase II analysis, respectively. After the completion of the two phases, NASA concluded that FDM had proven itself successful in the environment of space.

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Table 1: List of Phase I products (Bean, et al., 2016). Phase I: Specimen Description

1. Calibration coupon 2. Extruder plate

3. Layer quality specimen 4. Tensile coupon

5. Compression coupon 6. Flexure coupon

7. Negative range specimen 8. Torque coupon

9. Crowfoot 10. Structural clip

11. Positive range specimen 12. Tensile coupon

13. Compression coupon 14. Flexure coupon

15. Tensile coupon 16. Compression coupon

17. Flexure coupon 18. Tensile coupon

19. Microgravity structure specimen 20. Sample container (container)

21. Ratchet 22. Wire tie

Table 2: List of Phase II products (Prater, Werkheiser and Ledbetter, 2018). Phase II: Specimen Description Quantity

Total calibration coupons 1

Total tensile coupons 12

Compression coupons 14

Layer quality specimens 7

Additive Manufacturing Facility (AMF) - 2016 The next printer utilized on the ISS arrived in 2016, the Additive Manufacturing Facility (AMF). Both the 3DP and the AMF were designed and developed by Made in Space as part of the NASA Small Business Innovative Research/Small Business Technology Transfer (SBIR/STTR) initiative. The AMF, shown in Figure 12, was implemented for hardware manufacturing services for NASA and the U.S National Laboratory onboard. The AMF was built with consideration of the expertise developed during the 3DP experimental phases and also uses the FDM process. As such, the AMF has the capability to print larger and more complex products in less time than its predecessor (3DP Tech Demo Printer), with multiple aerospace grade plastics as an input (Made in Space, 2016a). Table 3 provides further specifications of the AMF.

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Figure 12: The Additive Manufacturing Facility (AMF) on board of the ISS (Made in Space, 2016a).

Table 3: Printing capacity of the AMF (Made in Space, 2016a). Parameter Performance

Volume (mm) 140 L x 100 W x 100 H

Material ABS, HDPE, PEI+PC (upgradable)

X/Y Resolution 0.025 – 0.44 mm with nominal of 0.15 mm

Z Resolution 75 μm layer height

Minimum Wall Thickness 1 mm

Threaded Holes >M10

Power Consumption 600 W

The AMF has produced over 100 parts to date (Prater, Werkheiser and Ledbetter, 2018). The printer is owned and operated by Made In Space and examples of parts created for the ISS are shown below in Table 4 (Werkheiser, 2018). In addition to the parts in Table 4, other parts manufactured by the AMF are as follows: Allen wrenches, clothespins, cable mounts, buckles, cable ties, nuts, bolts, sockets, bottles, ball valves, medical devices, springs, and many more (Made in Space, 2016b).

Table 4: Examples of AMF products printed on the ISS (Werkheiser, 2018). Specimen Name Purpose Creating Date

SPHERES Tow Hitch Joins 2 satellites together during flight. February 2nd, 2017

REM Shield Enclosure Radiation Monitor Brackets March 20th - June 16th, 2017

Antenna Feed Horn Space communication and navigation March 9th, 2017

OGS Adapter Adapter for OGS air outlet and fixture July 19th, 2016

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Refabricator - 2018 Tethers Unlimited Incorporated (TUI) received approximately USD 750,000 as part of NASA’s SBIR initiative to develop the Refabricator, a proof of concept 3D printer and closed-loop recycler delivered to the ISS in November 2018 (NASA, 2019b). The Refabricator, shown in Figure 13, can print tools and parts using plastic filament that can be made from recycling previously made plastic parts. The printer would allow effective re-use of the material from all printed parts when they are no longer needed. The Refabricator is currently undergoing testing on the ISS, and is the first integrated recycler and printer in space (NASA, 2017a).

Figure 13: The Refabricator (NASA, 2017a).

3.2 In-Development Techniques The Refabricator was the final printer to date that has been installed on the ISS. However, many additive manufacturing techniques are currently under development with plans to launch their 3D printers in the upcoming years.

NASA Initiative For the ISS, there are a number of systems that are currently being developed under the SBIR award. This award is categorized into three phases. In Phase I, systems are defined as establishing technical feasibility and concept and are awarded at a maximum of 125,000 USD in 2018. Phase II efforts include further development, R&D, and prototypes from Phase I and are awarded a maximum of 750,000 USD in 2018. In Phase III, these systems have been planned for commercialization and infusion as well as for flight on the ISS. This is the phase where hardware for current ISM payloads such as Refabricator were developed (Prater, et al., 2018). Examples of systems in Phase I and Phase II can be found in Table 5 below.

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Table 5: Systems in Phase I and II of NASA’s ISM technology development efforts (Prater, et al., 2018). System Name Phase Function Materials Company Fused filament fabrication (FFF), Multi-material, Vulcan Advanced Hybrid Made In Phase II weld based AM and automated hybrid Manufacturing System Space part movement manufacturing Compresses and heats 1 kg of Heat Melt Compactor solid non-biological waste Solid non-biological Phase II NASA (HMC) (packaging) to produce 200 ml of waste. water and a compact foam tile. Creates solid state bonds in Aluminum alloys, The ISS Fabrication various metal composites and metal composites, Laboratory (FabLab) materials. Milling and welding of metal foils. UAM Ultra Tech using Ultrasonic Additive Phase II finished parts as well as removes the oxide Machinery Manufacturing embedding sensors, and layer by using sound Technology (UAM) producing new composites waves (metal foil) Metal Advanced New or scrap metals Manufacturing Bot- Metal manufacturing and Tethers Phase II pressed into a metal Assisted Assembly recycling Unlimited ingot (MAMBA) Recycled materials ‘Medical-Grade and Food-Safe (plastics) using a dry Tethers ERASMUS Phase II Plastic Recycling and Sanitation heat sterilization and Unlimited System' UV sanitization Metal printer with filament Sintered Inductive Metal heated through induction and Ferromagnetic wire- Printer with Laser Phase II Techshot deposited. Melt completed by a fed metal filament Exposure (SIMPLE) low power laser Customizable Recyclable 3D foam packaging from recycled Plastic recycled from International Space materials. Phase II-X will upgrade the Refabricator into Tethers Phase II Station Packaging the Refabricator system and use filament - Material Unlimited (CRISSP) materials from it study in progress Reversible Copolymer Recycling and blending of Thermally-reversible Cornerstone Materials for FDM 3D materials into usable polymer Phase II polymer materials Research Printing of Non-Standard filament. Phase II-X will conduct with FFF Group (CRG) Plastics further material characterization Software and Tools for Software that complements Electronics Printing in Phase I NASA's effort in printable Software Techshot Space (STEPS) electronics Adaptive laser sintering Adaptive Laser Sintering System Metal Inks, low Tg for in-space printed Phase I Optomec (ALSS) for printed electronics Polymer substrates electronics

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Furthermore, a new ISM project award as part of NASA’s Next-STEP program was announced in December 2017. This project is a Multi-Material Fabrication Laboratory (FabLab) that seeks to have a high level of autonomy and should be able to integrate a suite of manufacturing capabilities. Some of the capabilities of FabLab were the ability to manufacture metals, ceramics, electronics and biological tissues in microgravity. The FabLab is suggested to fit within the current Expedite the Processing of Experiments to Space Station Racks (EXPRESS racks) on the ISS, including power and mass restrictions. In addition, it should possess terrestrial and autonomous quality control. The project is currently in the initial stages with three companies working on it: Techshot, Tethers Unlimited, and Interlog Corporation (Prater, et al., 2018).

ESA Initiative The European Space Agency (ESA) has student initiatives focusing on expanding the capabilities of additive manufacturing in space. An example of this is the Grain Power team, abbreviation of Gravity Independent Powder-based Additive Manufacturing. They have proposed to demonstrate the feasibility of powder- based additive manufacturing in microgravity by flying a prototype powder-based 3D-printer working in microgravity. This project was selected to partake in the European Space Agency program “Fly Your Thesis” and will fly on the ESA parabolic flight campaign in November 2019 (ESA Fly your Thesis, 2019).

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4 Other Manufacturing on ISS

As previously mentioned in the introduction, ISM includes other manufacturing technologies involving recycling, assembly, biological, and chemical processes. This section will focus on discussing the assembly techniques featured on the ISS, both onboard and it’s exterior.

Project Archinaut Made In Space has initiated Project Archinaut, a NASA funded project that was initiated in 2015 together with Northrop Grumman Corporation and Oceaneering Space Systems. The goal of Project Archinaut is to “enable autonomous manufacture and assembly of spacecraft systems on orbit” (Made In Space, 2018). Two projects which employ the Archinaut technology are underway: the first is Dilo, a spacecraft that transforms into a large reflector, while the second is Ulisses, a free-flying robot that manufactures and assembles large structures in space. The ISS is expected to be used as a platform to test Project Archinaut under microgravity environment since the prototype might require maintenance and calibration.

Canadian Robotic Arm Currently, with the development of robotic technology, increased agility and dexterity can be witnessed during the assembly and maintenance tasks conducted with the Canadian-built Mobile Servicing System. The system contains the Space Station Remote Manipulator Systems (SSRMS) and the Special Purpose Dexterous Manipulator (SPDM) (Flores-abad, et al., 2014). The SSRMS, also known as Canadarm2, was launched and installed on the STS-100 Mission in 2001. It is a 17-meter long robotic arm that has seven degrees of freedom and a symmetric structure capable of moving around the ISS like an inchworm. The Canadarm2 is operational on the ISS to fulfill the critical missions such as the ISS assembly and operation. It also plays a key role in the construction of the ISS (Flores-abad, et al., 2014).

A small, dexterous two-armed robot, SPDM is Canada’s other contribution to ISS. Since it features a 15 degrees of freedom dual-arm configuration, it can undertake highly dexterous tasks, such as installing, removing and servicing small payloads and Orbital Replaceable Units, with the help of Canadarm2. During operations, the Canadarm2 carries the payload within the SPDM’s range for repair, or picks up the SPDM and positions it close to the payload that requires servicing (King, 2001).

Figure 14: Shuttle Remote Manipulator System and Mobile Servicing Systems (Jordan, 2011).

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European Robotic Arm The European Robotic Arm (ERA) will be fixed to the Russian segment of the ISS. It is an 11-meter and seven degrees of freedom manipulator with two booms and a transferable base. The special tasks of the ERA include the installation, deployment and replacement of solar arrays as well as the placement of Orbital Replaceable Units (Laryssa, et al., 2007). The ERA has yet to be launched to the ISS. The system was expected to be launched on a Proton-M rocket in late 2019 but it has been postponed to 2020 (Cruijssen, et al., 2014; Aziz, 2019).

Figure 15: European Robotic Arm (ESA, 2006).

Japanese Experimental Module Remote Manipulator System Japanese Experimental Module Remote Manipulator System (JEMRMS), developed by JAXA, is composed of two arms with 6 degrees of freedom, a 10-meter long main arm with 6 degrees of freedom and a 2.2- meter long small fine arm. The main arm, which consists of booms, joints, television cameras, camera pan tilt unit, light and end effector, is attached to the Japanese Experimental Module Pressurized Module. The small fine arm will be attached to the end of the main arm and can perform agile tasks, such as exchanging the Exposed Facility (EF) with the main arm or placing Orbital Replaceable Units (JAXA, 2019).

Figure 16: Japanese Experimental Module Remote Manipulator System (Robinson, et al., 2008).

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Robonaut Robonaut 2 (R2) is a humanoid robotic platform manufactured by NASA and General Motors. It has been tested on the ISS to take on tasks that are traditionally performed by astronauts. It incorporates force sensing, thus allowing gentle operations to be performed with high dexterity. It is designed to be operated by people through interactive interfaces (Diftler, et al., 2019). R2 is still limited to very structured tasks and the ability to perform flexible tasks is still lacking. As such, complicated tasks will remain for now in the domain of astronauts’ EVA. R2 also requires special robotically compatible interfaces. It can attach itself using grippers to handrails and seat tracks (Badger, n.d.). R2 is supposed to relieve astronauts from EVAs, dangerous and/or hazardous, rapid responses and physically demanding tasks, and has proven its usefulness in test situations.

Figure 17: Robonaut 2 onboard ISS with astronaut Steven Swanson (Badger, n.d.).

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Chapter 1 Summary

This chapter established a framework for ISM that will be further utilized and expanded upon in Chapter 2. The current failures on the ISS will be leveraged to identify areas of further study while the crew needs set a baseline to compare and contrast against the deep space mission crew needs for a period of 3 years with no resupply. Current manufacturing technology has been identified to mitigate the risks of deep space while developmental technologies will be further elaborated upon along with their future applications for a sustainable spacecraft. Chapter 2 will determine the boundary conditions associated with a 3-year deep space mission and analyze solutions including feasibility, challenges, and risks.

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TER ONE

CHAPTER TWO

C DEEP SPACE CREWED MISSION

Chapter Two: Deep Space Crewed Mission

1 Mission Type

The current achievements and successes in space drive humans to push the exploration boundaries further. There has been discussion of humans going back to the Moon and even exploring as far as Mars. However, with these dreams come many challenges. This section will attempt to resolve some of these challenges with the implementation of ISM in those dreams. This section will build upon the foundation laid out in Chapter 1: ISS Analogue. However, prior to establishing the potential of ISM in a crewed deep space mission, a number of educated assumptions must be outlined. This section will outline the assumptions in regards to the location, duration, and crew size.

Location Regardless of the mission destination, space agencies and private companies are investing into long duration crewed deep space exploration missions. In fact, NASA, SpaceX and the Russian Government have laid out plans and desires to go to Mars in the coming years (Dunbar, 2018; Foust, 2018; Torossian, 2018). Hence, the location of this mission is assumed to be in deep space which is defined in the Introduction of this report as beyond the GEO. A particular celestial body has not been chosen as the destination since governments’ space priorities and plans are subject to frequent changes and redirection. For example, NASA under the Obama administration was tasked to focus on asteroid mining, while under the Trump administration, NASA’s focus has been shifted towards the Moon as a pit-stop to Mars (Patel, 2017; Leary, 2017).

Nevertheless, this deep space mission will need to feature ISM capabilities to increase the spacecraft’s autonomy while reducing costs. Due to the assumption that the spacecraft is in deep space, the practicality of cargo resupply is reduced. In fact, it is assumed resupply missions to this mission are not viable due to the enormous velocities and distances to overcome in a transfer trajectory (Saunders, 2017).

Duration Now that the location and term “deep space” has been established, the time period over which this mission will take place must be defined. According to NASA, a crewed mission to Mars can potentially take up to three years, considering (i) the time it takes to reach Mars from Earth, (ii) the time it takes to orbit Mars and perform research experiments and (iii) the time it takes to come back to Earth. Due to the relative positions of Earth and Mars during their orbits around the Sun, the distance between the two planets varies, thus allowing an optimal launch or return window to occur once every approximately two years (Frost, 2016). Although the location of this mission is not to Mars but to an arbitrary point in deep space, the maximum duration which is obtained from mission analysis is assumed for this mission as well. This is to ensure the full potential of ISM is exposed and exploited. Furthermore, NASA’s analysis for a mission to Mars also corroborates the need to eliminate mission reliance on cargo resupply and introduce ISM.

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Crew Size Currently, the ISS is populated by a maximum crew of six people. However, once US commercial crew vehicles become operational, the ISS crew size will be expanded to seven people (NASA, 2015a). Using the ISS as an analog, the assumption has been made that future deep space missions will need to accommodate a maximum of seven crew members. A relatively large number of crew members decreases social monopoly and escalation of internal conflicts while maintaining a high stimulus environment.

Hence, for the purpose of this report, it has been assumed that ISM technologies will be assessed under the framework of supporting a three years mission into deep space hosting a crew of seven crew members.

Since deep space crewed missions feature a different set of requirements when compared to the ISS missions, this chapter first introduces the critical factors that need to be considered for a deep space crewed mission from a human perspective as well as a spacecraft perspective. Afterwards, the report discusses how 3D printing and other manufacturing technologies can potentially be leveraged or adapted to address the critical factors previously mentioned. Following this section, a Technology Readiness Level (TRL) timeline for the different manufacturing technologies is provided, along with the challenges and risks associated with each technology. Finally, the financial, legal, political, ethical and environmental considerations of ISM are discussed.

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2 Human Factors

A deep space crewed missions, as described in the prior section, has more stringent crew demands compared to the ISS. Since the crew will be exposed to radiation and solitude from Earth for a longer period, the crew needs are more significant. Figure 18 lists and illustrates the habitation system elements that are crucial for the crew of current space habitats such as the ISS as well as the expected future deep space habitation system elements.

Figure 18: Diagram of current ISS and required future habitation systems elements according to NASA (Crusan and Gatens, 2017).

The sections that follow will discuss the particularities of a deep space mission compared to the ISS in regards to human factors. These factors include: (i) critical crew needs, (ii) waste management, (iii) medical supplies, and (iv) medicine. Once the differences in the two missions are established, technology which may have the potential to fill the requirement gap will be proposed.

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2.1 Critical Crew Needs Although humans have numerous requirements in order to survive a three-year deep space mission, this section will discuss the critical needs which are basic to life: (i) atmosphere, (ii) food, and (iii) water. Once the critical requirements are established, a technology to meet those requirements will be proposed.

2.1.1 Requirements The current crew requirements on the ISS for atmosphere, water, and food are discussed previously in Section 2 of Chapter 1. By extrapolating that data to seven crew members and three years, Table 6 is produced.

Table 6: Closed-loop efficiencies for Oxygen, Food and Water for a 3-year mission of seven members. Requirement 1 person per year Total for Mission

Oxygen 303 kg 6,363 kg

Food 226 kg 4,746 kg

Potable water 1,300 kg 27,300 kg

Hygiene water 9,490 kg 199,290 kg

The total mass of critical needs equates to 237,700 kg. This is the mass that is required if the mission were to depend solely on resupply missions. However, this mission is considered to be sustainable which means these requirements are to be satisfied by use of ISM, more specifically recycling. Referring back to figure

18, the efficiency of the current “closed” loop systems needs to be increased to 75% and 98% for O2 recovery from CO2 and H2O recovery, respectively. After performing the calculations, as shown in Table 7, the total mass saved is approximately 20,190 kg. This mass is saved in the initial mass of the cargo launched with the crew. Table 7: Mass savings with increased recycling rates. ISS Ideal Resupply with Resupply with Requirement Recycling Recycling Mass Saving ISS Rate Ideal Rate Rate Rate

Oxygen 42% 75% 3,690 kg 1,590 kg 2,099 kg

Potable water 90% 98% 2,730 kg 546 kg 2,148 kg

Hygiene water 90% 98% 19,929 kg 3,985 kg 15,943 kg

However, there is still a requirement for a large initial mass of critical crew needs in order to sustain seven crew members for three years as the recycling rates are not 100%. Hence, other ISM techniques which are more efficient need to be considered to provide higher recycling rates.

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Furthermore, the food requirements on the ISS are currently being satisfied solely by resupply missions. This cannot be the case for a deep space mission since a resupply will be very time consuming and cost ineffective. The food can also be launched with the initial cargo with the crew. In total, this would amount to approximately 4,700 kg of food (dry weight) for seven crew members for three years (Anderson, Barta and Lange, 2015). This amount of food would need to be stored for the whole flight duration. For such a mission, ISM of food is needed to fulfill the food requirements without excessive mass during launch.

2.1.2 Technology One type of ISM technology that may fulfill the atmosphere, water and food needs of crew members is bio-regenerative systems (Eckart, 1994; Lobascio, et al., 2008). The most important component of a bio- regenerative systems is photosynthesis. This process can perform most of the major functions for life support systems (Eckart, 1996). An example of photosynthetic effects on life support is discussed in Table 8.

Table 8: An example of a bio-regenerative Hydroponic Plant Growth Facility’s (HPGF) impact on in-space food production and atmospheric recycling capabilities (Lobascio, et al., 2008). Parameter Value

Cultivated surface 30m2

Cultivation volume 25m3

Tentative menu (% of edible mass) Soybean (14%) – Wheat (41%) – Dry bean (21%) – Lettuce (24%)

Caloric energy amount production 4475 kJ/day (38% of total need of one crew member in one day)

Macronutrient contribution per crew and day Carbohydrates: 43% - Proteins: 41% - Lipids: 22%

Food production (fresh basis) per day 435g

Water transpired per day 150kg (need of 5 crew members)

Oxygen production per day 863g (100% of need of 1 crew member)

CO₂ removal per day 1187g (120% of need of 1 crew member)

Air temperature in the HPGF 20 to 28 °C

Relative humidity in the HPGF 75%

CO₂ concentration in the HPGF 300 μmolCO2/molair

Pressure in the HPGF 101325 Pa

In the following sections, atmospheric, water, and food needs, and the impact of possible bio-regenerative systems in space are explored in further detail.

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Atmosphere Bio-regenerative systems can be used to replenish atmosphere. With current ISS systems based on mechanical gas purification, bio-regenerative systems can fulfill the role of a CO2 scrubber by using photosynthetic reaction to convert CO2 to O2 (Eckart, 1994). The opposite is also true, and biological systems can be used to convert organic waste to atmospheric gases like CO2 or CH4, which then can be used to fuel further biological growth or to create spacecraft fuel (Eckart, 1996).

Water Some bio-regenerative systems can utilize high amounts of water, as shown in Table 8 (Lobascrio, et al., 2008). However, bio-regenerative systems are also effective at recycling water, as some systems operate using wastewater as an input. As biological components like plants or microbes absorb and consume the nutrients and impurities from the wastewater, they produce clean water that can be gathered by moisture collectors installed on the spacecraft and can then be converted to consumable water (Lane and Schoeller, 2000). Two options of bio-regenerative systems for water reclamation from organic material exist: (i) aerobic bioreactors and (ii) anaerobic bioreactors. In aerobic bioreactors, microbes break down organic material to their base constituents (CO2, H2O, NH3 and biomass/sludge) in the presence of oxygen. However, in anaerobic bioreactors, where microbes don’t require oxygen, organic material is broken down into methane, CO2, and biomass/sludge (Eckart, 1996).

Food One option to fulfill the food requirements would be to grow food in space which may be achieved by utilizing hydroponics or aeroponics to produce fresh plants. It has been estimated that farming plants would need 30-50 m2 of farming area to fulfill one person’s nutritional requirements (Lane and Schoeller, 2000; Lobascio, et al., 2008). With a crew of seven people, potential farming requirement would be 210- 350 m2 to satisfy full complement crew daily nutritional needs. However, this is impractical due to the high area requirements.

Second, bioreactors can be used on the ISS to grow microbes based food. Although these microbes have significant nutritional value and fast production rates, an additional processing technique is required. Without a processing technique, these microbes are not edible. Further research on compact processing techniques for algae needs to be conducted.

Lastly, insects and/or animals can be utilized as fresh food sources. Insects have been explored as a food production option for space flights due to their fast reproduction and waste processing capability. As insects could eat leftover organic waste to grow biomass, they could be a good nutritional supply for astronauts and recyclers (Parry, 2007). Furthermore, animal cell lines can be grown to produce meat in laboratory conditions from cell cultures (Schwartz, 2016). These meat cells could then be combined with 3D printing to produce palpable food for astronauts without real animals. The 3D printing of animal protein could also open the window for more visually pleasing products during spaceflight. This could increase astronaut’s morale during long term missions (Terfansky, et al. 2013).

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2.2 Waste Management As with any system dealing with crew, particular attention must be paid to the waste produced and its disposal. This section extrapolates the waste data from the ISS and calculates the expected waste to be generated on a three-year deep space mission with seven crew members. Afterwards, multiple solutions to manage the waste are proposed.

2.2.1 Requirements As proven on the ISS, waste includes a variety of material, including wastewater, carbon dioxide, food packaging, clothing, cleaning materials, electronics, and broken parts, among others. Some of this waste is recycled to minimize the need for resupply such as water that is largely reclaimed but a certain amount of brine is left over that cannot be reused. The overall levels of waste for a crew of three for one year are detailed in Table 9 below.

Table 9: Breakdown of ISS waste for three people per year (Anderson, Barta and Lange, 2015). Waste Product Mass (kg) Method of Disposal Methane 224 Vented Carbon Dioxide 522 Vented Solid waste (clothing, trash, etc...) 1,248 Jettisoned (reentry) Brine 352 Jettisoned (reentry)

Total 2,346

This translates to 16,422 kg for a crew of seven for three years that must either be jettisoned or vented. While biological waste, methane, carbon dioxide, and brine may have use in a bio-regenerative system (outlined in the above section), the remaining solid waste (approximately 7,203 kg) can be stored, limited by onboard space, or simply jettisoned on route (Anderson, Barta and Lange, 2015). This mass can be lowered with new types of food packaging and clothing that have been developed and tested on the ISS (Broyan, Chu and Ewert, 2014). With this capability, zero waste would be the end goal. Otherwise, other methods of disposal must also be developed.

2.2.2 Technology There are four ISM techniques which can be implemented to manage the waste which will be produced by the mission: (i) input to bio-regenerative system, (ii) used as fuel, (iii) input to compactor, and (iv) input to the Refabricator. All these techniques, excluding the compactor, recycles the waste produced. The following sections will further discuss these techniques.

Bio-regenerative System One of the important functions of bio-regenerative systems is also their ability to recycle biological material. Organic waste created by human metabolism, food waste, or dead tissues is a major waste class in bio-regenerative systems and recycling these back to nutrients can fuel further growth cycles for plants

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Chapter Two: Deep Space Crewed Mission and other organisms. As ordinary waste treatment facilities are too large for spacecraft uses, two main methods have been identified to recycle organic materials in space: 1. Aerobic bioreactors that use oxygen to convert liquid waste and solid waste back into inorganic and organic compounds; 2. Anaerobic bioreactors that do not use oxygen to convert solid wastes and possible liquid wastes to organic and inorganic compounds (Eckart, 1996).

Table 10: Comparison of aerobic and anaerobic waste treatment (adapted from Eckart, 1996). Aerobic Bioreactor Anaerobic Bioreactor

Use ● Liquid Wastes ● Solid Wastes ● Maybe composting of solid wastes ● Possibly treatment of liquid wastes

Wastes Biologic decomposable fractions of liquid Biologic decomposable fractions of liquid and solid wastes. and solid wastes

Output CO2, H2O, NH3, (NO2, NO3), CH4, CO2, (H2), biomass/sludge biomass/sludge

Advantages ● Transition from an insoluble to a ● No gas consumption soluble state may limit the ● No leakage problems production rate ● Methane may be used as fuel ● Basic system for the treatment of ● Small amounts of well stabilized liquid wastes sludge may be used as fertilizer.

Disadvantages ● O2 -consumption ● Methane production ● CO2 -production ● Danger of inflammation of Methane ● Microbial activity may be influenced ● Slow decomposition by toxic components ● Very good controlling required ● Microbial activity may be influenced by toxic components

Fuel As shown in Table 9, the total mass of methane vented into space is 224 kg per year. Although it is difficult to recycle this excess methane within the ISS, it can be converted into fuel for propulsion (Anderson, Barta and Lange, 2015).

Space X is currently developing a rocket engine based on methane. This fuel has advantages of being relatively dense with a higher melting point than hydrogen, therefore, easier to store (Clark, n.d).

Heat Melt Compactor The Heat Melt Compactor (HMC) is being tested to take 1 kg of leftover solid, non-biological waste in the form of packaging and other material, and extract up to 200 ml of water from it, with the remainder being compressed into foam tiles to be stored. This would create 1,200 kg of water and reduce the waste from

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Chapter Two: Deep Space Crewed Mission approximately 7,203 kg to 4,800 kg. The foam tiles that are produced from the process could be potentially used to create privacy partitions, acoustic separations, and even radiation protection. Beyond the organizational and safety uses, such dividers would also have potential psychological benefits. Throughout the mission, the foam tiles would be assembled together as they become available to create these structural elements, offsetting the need for overall structural mass for a deep-space spacecraft (Broyan, Chu and Ewert, 2014). This minimizes volume for storage by 70-90%. Another factor in the handling of waste is the possible contaminant and microbial growth. The HMC includes a process of sterilization (via heating) in order to minimize this crew risk. This has been tested on the ground, with plans being made to install the system on the ISS, meeting all physical requirements of use alongside human spaceflight systems, including power (peak draw of 1 kW) (Fisher and Lee, 2016).

Refabricator Another method of disposal is the Refabricator by Tethers Unlimited Inc. (TUI), mentioned in Section 3.1 of Chapter 1. This device is the integration of two subsystems: a recycling plant and a 3D printer. Discarded plastics are placed in the recycler, heated to the point of melting and converted into high-quality filament, repurposing the material to serve as feedstock for the printer. This subsystem then fabricates new parts and tools with a range of applications going from food utensils to medical equipment. At this time, the Refabricator has only been designed to handle Utem, a sturdy plastic, but with limited uses. It is hoped to upgrade the system to utilize High-Density Polyethylene (HDPE), which has medical applications (Saunders, 2017). The device as-is is being confirmed to be safe for human use and is currently aboard the ISS for further testing (NASA, 2019b). In order to deal with metals, another device with similar applications is currently being designed: the Metal Advanced Manufacturing Bot-Assisted Assembly (MAMBA, also from TUI), with components under construction and testing, with a prototype slated for full integration (Prater, et al., 2018).

2.3 Medicine 2.3.1 Requirements The viability of long duration crewed space missions heavily relies on the crew’s health. On the ISS, the crew’s health plan is considered for relatively short stay periods and relies on the possibility of using the Soyuz for emergency evacuation to return to Earth within three to four hours (NASA, 2017d). For deep space missions, this luxury is unavailable. According to Jones, et al. (2004), there are no medical issues that would completely stop the first expeditionary missions to Mars given sufficient redundancy in life support systems. Yet, for a three year mission, a spacecraft must still provide a robust and complete medical system which can provide for a wide variety of medical issues, and a palliative capability must be available where resources are limited (NASA, 2017d). NASA (2018d) has identified the risk of ‘unacceptable health and mission outcomes due to the limitations of inflight medical capabilities’ as inappropriate for three year missions. One of the main causes being that there is no current capability to minimize medical system resource utilization during exploration missions. Utilizing new technologies such as 3D printing can significantly help in solving this problem.

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2.3.2 Technology Due to the crew size of seven, and the increased likelihood of medical issues arising, the amount of drugs that are needed for a crewed deep space mission significantly increases. The current solution for drug supplies is storage and resupply. There are a number of different processes and technologies to could be utilized to change this limitation. A number of technologies are discussed below. These technologies are all either developed terrestrially or being developed terrestrially as the technology is relatively new.

Inkjet printing This technique works by depositing tiny droplets of “ink” (other materials such as an excipient may also be used) onto a substrate. A thermal inkjet printers work by heating up the nozzle, which creates tiny air bubbles that then collapse leading to pressure pulses that eject ink droplets in volumes as small as 10 - 15 pico-liters. This allows for greater precision and the droplet size can be adjusted by changing the temperature gradient (Ventola, 2014).

Thermal inkjet printing has been demonstrated to produce solid dosage forms of prednisolone (a steroid medication which has been used to treat allergies and inflammatory conditions) (Meléndez, et al., 2008). Inkjet printing has been used to develop nanoparticles and implants containing antibiotics (Gu, et al., 2012; Huang, et al., 2007), as well as folic acid nanosuspensions (Pardeike, et al., 2011).

Fused Deposition Modelling (FDM) FDM is similar to thermal Inkjet printing, but instead of releasing ink, beads of heated plastic are ejected. This also means that the beads of plastic fuse to one another and previous layers before gradually cooling down. This technique often uses the same thermoplastics that are used in injection molding and as such, the products produced have similar stability, durability, and mechanical properties (Ventola, 2014). FDM has been demonstrated to produce anti-inflammatory and antibiotic tablets (Goyanes, et al., 2015).

ZipDose ZipDose technology has been developed by Aprecia Pharmaceuticals and have produced levetiracetam tablets (used to treat epilepsy) which is the first 3D printed drug to be approved by the Food and Drug Administration (FDA). The ability to 3D print the drug, removes the need for compression in the manufacturing process and therefore can achieve a large dose of the active ingredient (1000 mg of levetiracetam). An additional benefit from this method is that the tablet rapidly disintegrates with the sip of a liquid (Aprecia Pharmaceuticals, 2015). This process is the most developed technology for the 3D printing of medicine in terms of TRL, Manufacturing Readiness Level (MRL), and its approval from the Food and Drug Administration (FDA).

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Established Technologies

Table 11: Examples of pharmaceutical formulations that were developed by 3DP technology (Jassim-Jaboori and Oyewumi, 2015). 3DP Technology Dosage Forms Active Ingredients Drug use

Antibiotic for treatment of acute bacterial sinusitis, Implant Levofloxacin pneumonia, urinary tract infections Inkjet 3DP Nanosuspension Folic Acid A synthetic form of vitamin B9

Antibiotic for treatment of Nanoparticles Rifampicin tuberculosis, leprosy, and Legionnaires’ disease

Nebulizer used to treat Salbutamol sulphate wheezing and shortness of breath Thermal Inkjet (TIJ) Solution Steroid medication used to Printing treat certain types of allergies, Prednisolone inflammatory conditions, autoimmune disorders, and cancers

5-ASA - An anti-inflammatory 5-aminosalicylic acid (5- drug used to treat Fused Deposition ASA, mesalazine) and 4- Tablet inflammatory bowel disease Modeling (FDM) aminosalicylic acid (4- 4-ASA - An antibiotic primarily ASA) used to treat tuberculosis

Angiotensin-converting enzyme inhibitor used for the 3DP extrusion-based Captopril with Tablet treatment of hypertension printing Nifedipine and Glipizide and some types of congestive heart failure

Decongestant that shrinks A laboratory- scale Pseudoephedrine Capsule blood vessels in the nasal 3DP machine hydrochloride passages

Rifampicin and 3DP machine Multi-drug implant Anti-tuberculosis medication Isoniazid

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Advantages of 3D printing medication There are three major advantages that come with the 3D printing of medicine over conventional manufacturing methods: 1. Personalized drug dosing 2. Unique dosage forms 3. Complex drug-release profiles

Personalized drug dosing is one of the most evident advantages. The ability to change the size of each tablet or form allows the dosage to be adjusted. This not only reduces waste due to production of standard form sizes but also allows for specific customization to suit the patient. With a potential crew of 7 people, the ability to produce person specific drugs, saves on storing a vast amount of drugs for every crew member and drug wastage. One potential application of personalized drug dosage is the production of drugs that can facilitate faster recovery from radiation damage (radio-protectants). These drugs could be printed in advance if there is a known increase in radiation exposure. The dosage of these drugs could be increased or decreased depending on the severity of the exposure.

Figure 19: FabRx’s chewable medicines showing different dose sizes (FabRx, 2018).

Unique dosage forms allows for the drug to not just be printed in a tablet or capsule form but another form that may be more suited to the user. In a microgravity environment, this may be a great capability for both the patient and the process. Allowing different forms of administration through manufacturing techniques on board greatly increased the adaptability of the drug production.

Complex Drug profiles are now becoming a much more researched topic due to the development of 3D printing. Traditionally, drugs have the active ingredient and substrate together in a homogeneous mixture, now however, 3D printers can print barriers between active layers only 200 microns thick allowing for controlled drug release (Ventola, 2014). Administering multi-layer drugs, with steady state release or pulsating mechanisms allows crew members to reduce the time allocated to medication and can also ease the use of medication.

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2.4 Medical devices 2.4.1 Requirements As discussed in Section 2.3 of this Chapter, future long duration exploratory missions with decreased access to support from Earth will require on-board medical personnel and equipment to be more effective and independent. Currently on the ISS, a medical condition could be resolved more easily than the same medical condition occurring in deep space.

On the ISS, there are several medical kits (NASA, 2016b): 1. Medical diagnostic pack - blood pressure cuff, thermometer, oximeter, stethoscope, etc. 2. Medical supply pack - such as bandaids, tapes, gloves, needles, and syringes. 3. Minor treatment pack - Bandaids, gloves, dental kit. 4. Oral medication pack. 5. Physician equipment pack - minor surgery kits. 6. Topical and injectable medication pack.

All of these packs contain many disposable pieces of equipment in addition to other routine testing consumables. It can be seen that an important part of the weight is used for medical consumables. In addition to this, many of these parts are stored but never used (Owens and de Weck, 2016).

ISM can help enable deep-space missions by reducing the stored current medical supplies and related weights. In addition to this, the flexibility of design that becomes available when using additive manufacturing enables for the creation of new types of consumables. This allows for new approaches to be taken when it comes to medical devices for use in spaceflight.

Current on Earth 3D printing technologies have proven capable of printing medical related plastic consumables and medical graded materials. These methods will be evaluated for space mission requirements.

2.4.2 Technology In the medical field, consumables are usually syringes, catheters, tubes, and needles that are mainly simple parts made out of plastics or metals. These components are made for one-time use in order to maintain patient personal hygiene and reduce the spreading of infections between crew members (NASA, 2016b). The feasibility of 3D printing methods in supplying these needs will be further described.

General Plastics and Polymers Consumables 3D printing of medical consumables on Earth is not very commercialized yet since it is much cheaper to mass produce by molds. However, in space from reasons previously described it can still be worthwhile to print the consumables. When looking at production of consumables in space, the most obvious technologies are plastics which are already proved as operational technology in space. Figure 20 shows some of the different medical consumables that have been printed using current 3DP technology.

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Figure 20: Surgical tools, splint, face mask, otoscope and a fitting (3D4MD, 2019; 3D printing Industry, 2019).

When looking at long exploration missions, the variety and amount of these consumables will be very high. Medical surgery may be a matter of essence when astronauts will be staying longer periods without the possibility of returning to Earth and consumables will not be replenished at the same frequency as is currently being done on the ISS.

3D printing plastics terrestrially is quite developed and is used in high-end medical operations where specialty and customized tools are required. These tools and components are printed by the technologies presented in Table 12.

Table 12: Printing technologies for medical devices (Engatech, n.d.; Stratasys, 2019).

3DP Material Resolution Usage Bio Sterilization technology compatibility

Polyjet Thousands of materials with <100 micron Complex prints with Yes No different thermal behavior, different transparency, rigidity and characteristics in one color such as ABS, ASA, print. Detailed and MED610 provided by smooth precise Stratasys. finishes. Highly flexible.

Fused Tens of materials such as ABS, >100 micron Durable, tough, Yes Yes Deposition PPSF, Nylon. thermoresistant, tight Modeling tolerance components

DMLM Stainless steels, Chrome-cobalt 20 microns Metallic tools of all Yes Yes alloys, Bronze, Nickel and kinds with high finish aluminum alloys

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These technologies have been proven to be capable of sterilizing the final product through the printing process and can use many biocompatible materials. In addition to these processes, the company ‘Copper 3D’ have developed a printing filament that has a nano-copper additive within the filament the gives it antibacterial properties (Copper 3D, 2018). These qualities are highly desirable for production of medical components (Perez, et al., 2012; Flynn, et al., 2016).

Patient Specific Consumables Long space missions under microgravity will have implications on human structural systems such as bones and muscles. The ability to 3D print patient specific casts and body support may be of benefit for crew suffering from these conditions. There is commercial terrestrial examples such as Activarmor (figure 21) and orthopedic corset by Wasp (Buscaroli, 2018).

Figure 21: Example of patient specific 3D printed consumables (Activarmor, 2019).

With advanced capabilities for larger prints, other space oriented wearable medical devices such as printed contraptions to regulate blood flow from limbs to upper body in order to mitigate the adverse effects of microgravity can be considered. Printed personal body radiation shields may also be a future application of such technology. The casting requires scanning and specific design which can be done prior to the mission with CAD files stored or sent in case of an emergency.

Printing for Training Space Medical Crew Crew level of expertise in medical operations is not high. To date, a medical surgeon is not an integral part of space mission’s team and that may not change. With 3D printing technologies, it is possible to print surgical aids to help a crew member perform a medical surgery that they are unfamiliar with. An example of this would be for a dental procedure. If a crew member’s dental map was stored, a dentist on Earth could upload a CAD model with the exact spot to drill that crew members teeth. This would then be 3D printed, and used for the medical procedure. 3D printing of physiological models for training is very developed and is offered by commercial companies such as Stratasys and Materialise (Materialise, 2019) and demonstrated by operating hospitals (O’Neal, 2016).

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Figure 22: 3D printed heart model by Stratasys (Model of patient's left atrial appendage, n.d.).

Metal Consumables Much like plastic consumables, steel consumables are also part of the medical kits onboard the ISS and future exploration missions vehicles. However, metallic medical instruments constitute a lower percentage of the medical kits in terms of both mass and volume. As such, developing a metal printing technology for space mission may not be worthwhile. If such capability will exist, metallic medical consumables could also be printed for the benefit of the medical services onboard.

As with the plastic consumables, simple common metallic tools will not be produced terrestrially by 3D printing processes but rather by more efficient high-volume traditional methods that require larger infrastructure. Terrestrially 3D technologies are reserved for high-end/cutting-edge medical procedures. In space 3D printing technology can be utilized for simpler objects just to save the space and cost required to send it from Earth.

For example, on Earth GE produced a special stainless steel tool to assist in hip joint replacement. This tool is patient-specific 3D printed using Direct Metal Laser Melting (DMLM) technology (see Table 12 above for DMLM properties) (GE Additive, 2018a).

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Figure 23: 3D printed hip joint replacement tool by GE (GE Additive, 2018b).

This technology on Earth is expensive and required for very specific needs but in space if available can be used in many other applications as well as printing simple metallic medical and surgical tools.

Figure 24: Metal 3D printed automatic suturing tool from Sutrue (3D printed suturing tool, n.d.).

Future exploration missions may require this capability of manufacturing for simpler tools such as tweezers, surgical blades, needles and other special tools requiring metallic properties.

2.5 Mental Health The presence of humans in space brings with it a number of unique risks in comparison to those on Earth. These space-specific challenges all represent threats to the completion of mission goals. This would be significantly amplified by undertaking deep space missions where mission time, mission importance and physical dangers would be higher than any previously attempted. This section aims to provide an overview of one specific risk to mission success: Human Psychology.

Deep space exploration, a currently untested expedition type, has been classified as high risk to mental health (NASA, 2016a). The presence of unknown mission parameters implies that psychiatric and psychological developments could become significant hazards (NASA, 2016a). Current data on this subject

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Chapter Two: Deep Space Crewed Mission comes from two areas: analog on-Earth studies and in space human behavior research. Both sources shall be further discussed.

2.5.1 Requirements The psychology of being in space is a relatively young subject (Harrison and Fiedler, 2011). This began with concern of how intercultural and interpersonal stressors could impact on an Astronauts’ cognitive capacity to complete their work (Harrison and Fiedler, 2011). Even now, when working in a multicultural environment is increasingly commonplace, electroencephalogram (EEG) studies of analog mission participants found increased subconscious anxiety in regards to images of participants from other socio- cultural groups (Bubeev and Ushakov, 2010). Significant decreases in emotional wellbeing and interpersonal relationships have been positively correlated with space stressors in both Russian space flights and analog missions (Manzey, Schiewe and Fassbender, 1995). Further to this, a lack of participant or crew cohesion has been directly correlated with increased human errors (Landon, Vessey and Barrett, 2016). Terrestrial based research has consistently supported the concept that increased psychological stress is detrimental to human cognitive skills (De la Torre, et al., 2010). Even mild levels of psychological symptomatology (sub-clinical) could impact on individual health, team cohesiveness and task performance levels (NASA, 2016a).

As stated, high risk actions, such as Extra Vehicle Activities (EVAs), have a high cost if unsuccessful - a small error on Earth could mean death in space (Bishop, 2011). The ISS provides a good platform to understand the impact of living in space on astronauts. The astronaut experience can be characterized by high levels of monotonous work in a multicultural environment with significant penalties for error (up to and including death) (NASA, 2016a). The proposed Deep Space Mission would include all these elements with the additional risk of distance from rescue. No psychological emergency has occurred in space as of yet, suggesting a validity to current approaches - however, it is unknown as to the transferability of these techniques to different mission objectives, types, and crews (NASA, 2016b). Outcomes of distress in extreme environment living situations appear to be dictated by the interactions of the physical environment being experienced, the social context and individual personality types (Bishop, 2011).

Human factors research, such as discussed here, has developed a strong base of evidence to support the hypothesis that decreasing levels of psychological and/or physiological stress, while simultaneously increasing validated support techniques, will allow humans in space to work for longer with greater levels of success (Landon, Vessey and Barrett, 2016). The importance of psychological support has been identified as a significant variable requiring risk mitigation. This is for the protection of both the humans involved in a space based mission as well as for the mission itself.

2.5.2 Technology Two micro-mitigation plans shall be proposed in the following section in support of the mental health needs of a crewed deep space exploration mission. These are: 1. 3D printing of recreational models and pieces to enhance crew leisure time options; 2. 3D printing of room dividers to allow astronauts autonomy of environment and enhanced privacy options.

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Agencies provide psychological resilience training to provide the skill base to allow self-care in supporting psychological wellbeing (Manzey, Schiewe and Fassbender, 1995). Personal and social resources are essential predictors of well-being (Beutel, et al., 2010). Support is provided preflight, during flight, and post flight to this end (Harrison and Fiedler, 2011). Complimentary to this plan, the 3D printing of items available on Earth, such as games, could be used to enhance the recreational and social options of crew and thus decrease the risks of monotony of routine. A cursory search of design databases identified over 100 available game designs, free to download (Yeggi, 2019).

An offshoot of the creation of recreational models could be the use of in-situ printers to create 3D models of loved ones. This technology is currently available in terrestrial markets (Watkin, 2017). On a three year mission, a crew member’s connection with loved ones on Earth would be very abstract, utilizing email and video conferencing. The distance of important relationships could become extremely distressing. Crew, for example, may be forced to watch their child's birth and adolescence via a computer monitor. The ability to create models of their child throughout this time period could allow crew members to create a more tangible connection to what they are missing. This may not lessen the distress of missing their families but it may help make this distress more manageable. Tactile models of other items from home may also provide a calming support technique for homesickness, such as models of home towns or countries. This concept has never been tested in space.

Another potential support plan for the mission in question could be the use of the design of the habitat used. Living and relying on a space station or shuttle is, by its nature, to give up a certain level of autonomy inherent to living on Earth. Humans are constrained by the size and layout of the habitat area, reliance on life systems and the pressures of crew size on available space (Imhof, 2003). Input from crew have indicated areas requiring development in a design context to create a more human friendly habitat. For example, those who worked on the Mir station requested a reduction in background noise levels (Imhof, 2003). The aforementioned areas of note on Earth would generally be considered basic tenets of wellbeing, suggesting that unless adequately addressed in orbit, manufacturing facilities may struggle with worker retention.

“Owning a location” appears to be an unspoken wish for those humans utilizing space habitats. Imhof (2003) speculated that a sectioned, recreation specific area may be of use in supporting this. This allows individuals to close the door behind them creating their own private area, separate from station work. The ability to 3D print panels and dividers that could then be recycled would allow crew an autonomy and variability of environment never seen in space habitats.

Those products can be created utilizing additive printing techniques currently available and used both on Earth and in orbit thanks to the 3DP demo printer (refer to Section 3.1 in Chapter 1). Design plans for generic forms of both product types are currently available for free on multiple platforms with multiple successful uses (Grunewald, 2016; Yeggi, 2019). While the necessary printer has been tested in orbit, neither product type has been printed in orbit and thus requires in-situ testing for qualification.

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The elimination of psychological stressors in this mission type is not possible. However, the aforementioned approaches of bringing “Earth to Space”, may allow micro mitigations to be utilized to create an impact that is significant in its totality. The aim of this mitigation being the promotion of crew wellbeing and thus the promotion of mission objectives.

2.6 Radiation (Crew)

2.6.1 Requirements Radiation continues to pose an enormous risk to agencies considering long-term crewed missions outside of the Earth’s magnetosphere. While terrestrial levels of radiation are relatively low, solar and galactic radiation stretches across our solar system, making deep space travel extremely dangerous for humans. The sun provides the majority of the damaging radiation in our solar system - however, galactic cosmic radiation (GCR) is also present stemming from radiation within the Milky Way galaxy (Rask, et al., 2008).

The two primary types of radiation are ionizing and non-ionizing. Both radiation types cause critical damage. However, non-ionizing radiation can be shielded against due to its relatively long wavelength and lower energy. Ionizing radiation is primarily responsible for the conundrum space agencies face in crewed space flight. Ionizing radiation is composed of high energy particles or photons capable of removing electrons from atoms or molecules (Rask, et al., 2008). Ionizing radiation can be categorized into 3 primary groups depending on its source: 1. Trapped radiation belt particles (Van Allen) 2. Cosmic rays 3. Solar particles (Rask, et al., 2008)

While most people on Earth are protected from these various types of radiation, astronauts are highly exposed and largely unprotected.

There are three critical factors that dictate how much radiation an astronaut receives: solar cycles, altitude from Earth (distance from the magnetosphere), and the individual’s susceptibility (Rask, et al., 2008). The sun solar cycle is roughly 11-year which helps astronomers and scientists predict the severity, number of solar spots, and coronal mass ejections responsible for detrimental radiation throughout our solar system (Rask, et al., 2008). In addition, each individual is more or less susceptible to radiation similar to how some families have a higher likelihood for certain types of cancer due to their genetic predispositions. Finally, altitude dictates an astronaut's protection from this harmful radiation. The Earth’s magnetic field blocks the majority of this radiation. However, astronauts on the ISS, at an altitude of 350-400 km, are exposed to approximately 40 times the amount of radiation people are exposed to on Earth’s surface within a single year (Rask, et al., 2008).

As can be seen in Table 13, age and gender also dictate the standard astronaut career exposure limits. This is primarily due to the risk of various types of cancer associated with gender and age. To compare, terrestrial humans are only exposed to .0036 Sieverts (Sv) per year (Rask, et al., 2008).

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Table 13: Career astronaut limits for males and females at varying age (Rask, et al., 2008). Career Exposure Limits for NASA Astronauts by Age and Gender

Age (years) 25 35 45 55

Male (Sv) 1.50 2.50 3.25 4.00

Female (Sv) 1.00 1.75 2.50 3.00

On the ISS, radiation is measured through either passive or active dosimeters. These devices are capable of measuring the astronaut's dose equivalent which is a standardized radiation measurement metric taking into account the different types of ionizing radiation that can induce biological damage (Naef, 2018).

Mission types have been categorized to compare expected radiation exposure levels shown in Table 14. Having selected a 3-year mission, Mars exposure estimates will most likely be synonymous with this mission type. With no improvements in technology, this exposure is over 100 times the yearly radiation exposure on Earth and excludes 25-year-old women from participating in the mission. Clearly, there is a need for better radiation protection to reduce the risks posed in a long-term mission.

Table 14: Mission specific radiation doses (Rask, et al., 2008). Mission Type Radiation Dose (mSv)

Space Shuttle Mission 41-C (8-day mission orbiting the Earth at 460 km) 5.59

Apollo 14 (9-day mission to the Moon) 11.4

Skylab 4 (87-day mission orbiting the Earth at 473 km) 178

ISS Mission (up to 6 months orbiting Earth at 353 km) 160

Estimated Mars mission (3 years) 1,200

Currently, the primary method of radiation protection on the ISS is through structural shielding. The structure is composed of 1 cm thick aluminum. Certain areas contain additional shielding, with a blanket just inside the aluminum structure containing six layers of Kevlar and six layers of Nextel (National Research Council, 1997). Additional methods and materials for protection are under investigation at various space agencies in preparation for longer missions outside at the limits of Earth’s magnetosphere.

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Some of these materials, such as polyethylene, have to ability to be 3D printed to maintain adaptability during missions.

2.6.2 Technology Radiation exposure for astronauts poses a significant technology gap for crewed deep space exploration. Various technologies are currently under development to mitigate the risk to astronauts. However, in Section 2.6.1 of this Chapter, it was shown that a 3-year mission to deep space would increase the typical yearly exposure limit derived from the ISS from 150 mSv to 1,200 mSv (Rask, et al., 2008). There are many mitigation strategies including improved radiation shielding, pharmaceuticals, diet, and personalized plans. This section will focus on primary radiation shielding for the spacecraft and secondary radiation shielding techniques to optimize the radiation exposure an astronaut is subjected to.

To create reasonable expectations in technological advancements prior to a 3-year duration crewed mission, the maximum exposure limit will be maintained at approximately 150 mSv. This value is backed by significant research and ISS participants are not readily eager to relax this baseline. However, based on the various 1-year missions on the ISS, such as astronaut Scott Kelly’s, research may prove that exposure to 320 mSv may be within reason. The 320 mSv value is an extrapolation from current ISS 6-month mission data. That said, there are various approaches to shielding that will assist in simplifying the overall spacecraft design. The following shielding schemes have been identified by NASA as areas in the spacecraft that would benefit from increased shielding efforts (Clowdsley and Simon, 2013): 1. Personalized Shielding; 2. Individual Crew Quarter Shielding; 3. Crew Quarter Shielding; 4. Entire Spacecraft Shielding.

This appears a very logical technique to mitigating the risk of astronaut exposure. Astronauts sleep on average 7-8 hours on the ISS and spend another 2-4 hours per day in crew quarters talking with family members, crew members, or eating meals (Rovera, 2014). This means that astronauts spend approximately half their day in one contained area. Increased radiation shielding in these areas will significantly aid in protections from Galactic Cosmic Radiation (GCR) and solar radiation.

One of the current barriers to improving radiation shielding is the mass associated with developing an adequate shielding technology. To put this in perspective; it would take well over 60 heavy lift launches, each capable of carrying 40.5 tonnes of aluminum, to meet the radiation shielding baseline set by the ISS at 150 mSv (Singleterry, 2013). This is highlighted by Figure 25 along with other potential materials under consideration.

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Figure 25: Effectiveness of different radiation protection materials vs. launch mass (Singleterry, 2013).

Based on Figure 25, aluminum and multi-layer insulation (MLI) are not feasible to use as the primary method of radiation shielding throughout the entire spacecraft. The following lists the primary methods proposed for long duration deep space missions based on research being undertaken by various space agencies (Singleterry, 2013): 1. High-density liquid hydrogen wall; 2. Liquid hydrogen wall; 3. Water wall; 4. High density polyethylene; 5. Aluminum + MLI; 6. Active radiation shielding.

Active radiation shielding, such as magnetic field generation from the spacecraft, will be excluded from this report due to its low TRL and high power demands. Liquid walls are one of the primary suggestions for radiation shielding improvements and Figure 26 shows a very basic design for how this technique would work within a spacecraft for cryogenic liquid hydrogen. The open pocket in the middle of the diagram titled ‘Crew Quarters’ is the daily operating area for the astronauts while the 2 gray circles depict aluminum shielding encapsulating the liquid highlighted in green.

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Figure 26: Simple hydrogen shielding design.

Cryogenic hydrogen and water walls have more effectively shielded against the high ionizing energy particles emitted by the sun or elsewhere in the solar system (Singleterry, 2013). Polyethylene also provides an interesting solution and can be utilized in tandem within the MLI for typical shielding systems. Table 15 is a trade-off study of the various techniques and some key parameters associated with radiation shielding.

Table 15: Trade-off to provide advantages and disadvantages of various shielding methods (Singleterry, 2013). Shielding Method Density Effectiveness Material Secondary Use with Equivalent Handling Danger Mass

Liquid Hydrogen Wall Low High High Fuel

Polyethylene Medium Medium Low N/A

Water Wall Medium Medium Low Closed loop water system for onboard support

Aluminum with MLI High Low Low N/A

Based on the trade-off study, it was concluded that liquid hydrogen is the most effective and useful radiation shield. Cryogenic hydrogen poses a large risk to the crew due to its combustion characteristics so the engineering solution will need an extremely cautious approach to ensure unnecessary danger is not introduced to the crew. However, it is also acknowledged that a combination of methods are needed in order to properly shield the crew from hazardous radiation.

Liquid hydrogen and liquid water shields support the sustainable spacecraft objective by having alternate uses such as fuel and the closed loop water reclaiming system. The fuel can be used for emergency maneuvers or planetary lander capabilities while the water can be used at the final destination for bio- regenerative systems.

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The final recommendation for radiation shielding are shown in Table 16.

Table 16: Recommendations for radiation shielding in spacecraft. Compartment Type Shielding Method

Personalization Polyethylene stitching in crew clothing

Individual Crew Quarter Water bladder sleeping bags, pharmaceuticals, and dietary restrictions

Crew Quarters Common Area High density cryogenic liquid hydrogen wall

Spacecraft Repair Aluminum shell with MLI layered with polyethylene. Repair if radiation shielding is damaged in transit.

Additive manufacturing plays a larger role for the personalization and repair. The suggestion in Table 16 supports specialized crew clothing with integrated polyethylene structures and, more importantly, increased shielding around the most susceptible organs. Stratasys is an industry leader in terrestrial printing and has begun to work with fashion designers to design and print specialized clothing and wearables (Swack, 2016). This is a very underdeveloped field terrestrially and space agencies will have to drive advancements to implement solutions involving additive manufacturing clothing and wearables. However, this technology would help customize the way space agencies react to radiation threats.

Repair operations will also be heavily supported by additive manufacturing. If there is damage during transit to the radiation shielding, SLS or FDM printers can be utilized to print aluminum or polyethylene to help repair and bolster the radiation shielding. The Refabricator and the MAMBA are good candidates to recycle and reprint parts for radiation shielding due to their recycling ability as discussed in Chapter 1, Section 3.1. The HMC system discussed in Section 2.2.2 of this Chapter can be utilized to create radiation shielding tiles using a closed loop system. The ability to adapt and react to unforeseen situations remains the greatest advantage of additive manufacturing and holds true for radiation shielding. 3D printing of pharmaceuticals for radiation protection is further discussed in Section 2.3 of Chapter 2.

The plethora of suggestions shown in Table 16 improve on today’s baseline, but there is still a substantial gap in meeting the 150 mSv goal. The radiation limit may need to be relaxed for a 3-year mission to become more feasible and experiments on the ISS will need to be conducted to quantify and verify the suggested recommendations.

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3 Technical Factors

The previous section discussed the human requirements as well as the ISM technologies that can efficiently and sustainably address those requirements. Similarly, the below section discusses the technical requirements from a spacecraft perspective as well as the ISM technologies that can address those requirements.

3.1 Radiation 3.1.1 Requirements The spacecraft will pass through many varied radiation profiles on its journey and must be adequately prepared for all of them. There is the thick, dense, low-energy plasma of LEO (Schrijver and Siscoe, 2012), the highly charged particles of the Van Allen belts, and the energetic plasma and cosmic radiation beyond the reach of Earth’s magnetosphere (Barth, 1996). Each event can have a variety of deleterious effects on spacecraft subsystems, and so each must be prepared for and mitigated.

The low energy plasma found in LEO leads to spacecraft charging. This effect is intensified by the higher energy plasma and charged ions found in GEO and beyond, with possible floating voltages of several thousand volts during a solar storm. An electric charge building up across the surface of the spacecraft is, to some extent, unavoidable. If any parts of the spacecraft exterior are electrically isolated from the rest, this can lead to arcing, damaging the spacecraft in the process (Schrijver and Siscoe, 2012).

Although short missions may only gain a floating surface voltage of around 0.5V, multi-year missions can build up much higher charges; 10,000V has been observed in rare cases. The ISS can have a floating potential of up to -140V. Although this is thankfully too low to cause arcing between the station and resupply shuttles, it does cause other issues – the thin anodized coating on the outside is gradually stripped away by the difference between this float and the charge on the outside of the coating, which does sometimes lead to arcing (Schrijver and Siscoe, 2012). Additionally, if the wires between solar cells collect a charge, the potential difference across the solar array can be affected and the current produced can drop drastically. To counter this, the floating voltage is reduced by a Plasma Contactor – a device that charges Xenon gas and ejects it to reduce the floating voltage (Patterson, et al., 1994).

Solar arrays are also particularly vulnerable to total dose effects of radiation over time, leading to degradation effects and a loss of efficiency (Figure 27). For long missions a significant degree of over- engineering is required to allow for sufficient power generation at all stages. The same occurs with many other electronic subsystems in a spacecraft – after biological tissue, electronics are the most vulnerable components to radiation-induced degradation (Schrijver and Siscoe, 2012).

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Figure 27: Solar Cell Power Loss vs Radiation (700 km altitude, 30° inclination) (Schrijver and Siscoe, 2012).

Sensitive semiconductor electronics are also at risk of Single Event Effects (SEEs). A particle with an energy of the order of GeV can penetrate an electrical system and have a number of effects. The simplest is a single-event upset, where a bit is simply flipped from 0 to 1. This can be corrected for with simple error checking by software. Other effects, however, can include a latch up, causing an electrical feedback loop across a semiconductor junction until it is powered off, or rupturing the insulating layer and rendering the gate useless. The lower the voltage of a subsystem, and the smaller it is, the more vulnerable it is to these effects, causing problems for any spacecraft designer concerned with their mass and power budgets (Schrijver and Siscoe, 2012).

One potential solution to these issues is to 3D print replacement electronics and solar arrays as needed, as well as printing additional radiation shielding and electrical contacts for repair purposes.

3.1.2 Technology Different shielding techniques have already been covered in depth in Section 2.6 of Chapter 2. Apart from the possible use of recycled waste printed into radiation shielding discussed in Section 2.2 of Chapter 2, 3D printing could be used to replace damaged or non-functional electronic components, saving space and producing highly customizable circuitry on demand.

3D printing of electronics has been researched under terrestrial conditions – Optomec has successfully printed electronics onto substrates, both 2D and 3D. Using a method called Aerosol Jet printing, a conductive material can be aerosolized and sprayed onto a film in lines as thin as 10μm, and is able to print resistors, capacitors, sensors, antennas, and transistors. Use of a dielectric can also produce the effect of a multi-layer circuit board, allowing for complex circuitry to be produced on very thin, lightweight film (Optomec, 2018a). nScrypt have developed the Factory in a Tool (FIT) platform for the US military, which is capable of using a wide range of materials and substrates to print a variety of things – circuitry

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The printing of solar panels is also difficult to achieve, but has also been proven in terrestrial environments. Optomec has used their Aerosol Jet printing technique to print solar cells (Optomec, 2018b), and research by the Victorian Organic Solar Cell Consortium has produced films of solar cells printed on organic material (O'Neil, 2014). The circuitry of the array can be printed with the electronic circuitry methods listed above, with large metal printing and structural assembly being used for the structure of the array. This could make use of Made in Space’s Archinaut, or a similar system discussed in Section 4 of Chapter 1. Assembly can be completed manually by crew members, but automated assembly of electronic components has already been flight-tested by Made In Space, with the Satellite Manufacturing Machine (SMM) assembling and linking several electronic components under microgravity conditions during a parabolic flight (Made in Space, 2017).

3.2 Communication The ability to communicate and exchange information with a spacecraft is critical to ensure its normal mission operations and long-term survivability. The section below discusses the requirements of a deep space mission in terms of communication as well as the ISM technologies that can be leveraged to address those requirements.

3.2.1 Requirements A crewed mission on a three year journey into deep space will require featuring sufficiently reliable and efficient communication systems and interfaces to ensure the maximum possible throughput is achieved. As electromagnetic waves propagate in free space, their energy is spread across an increasing volume of space. The ratio of the available power at a receiving antenna and the power of a transmitting antenna can be given by the below formula, derived from Friis’ equation (Shaw, 2013).

푃푟 휆 2 = ( ) 퐺푟퐺푡 푃푡 4휋푅 Where the below assumptions and definitions apply:

4휋푅 4휋푅 – Free-Space Path Loss (FSPL) is given by ( )2 , or 20푙표푔( ) ; 휆 휆 푑퐵 – R >> 휆 such that both antennas are in the far field of each other;

– Pt is the power delivered to the terminals of an isotropic transmit antenna (in Watts);

– Pr is the available power at the receiving antenna terminals equal to the product of the power; density of the incident wave and the effective aperture area of the receiving antenna proportional to 휆 2 (in Watts);

– Gt is the transmitting antenna gain;

– Gr is the receiving antenna gain; – The antennas are correctly aligned and have the same polarization; – The antennas are in unobstructed free space, with no multipath;

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– The bandwidth is narrow enough that a single value for the wavelength can be assumed.

Based on the above equation, the available power at the receiving antenna (Pr) is inversely proportional to the distance between the two antennas (R). As such, the further a spacecraft travels into deep space, the less power its antenna can receive and the more power it needs to send data, thus limiting the data rate that can be transmitted. This can also be characterized by an increase in the Free-Space Path Loss (FSPL) as the distance between the two antennas increases.

In addition, although higher frequencies (i.e., shorter wavelength) can transmit more data than lower frequencies within the same amount of time, higher frequencies experience a higher FSPL than lower frequencies. An example of the challenges in this area can be attested by the eccentricity of Mars’ orbit causing the distance between Earth and Mars to vary tremendously, from a minimum distance of 55 million km to a maximum distance of 400 million km at superior conjunction (Ho, Golshan and Kliore, 2002). As such, the FSPL between Earth and Mars is much higher than FSPL between Earth and GEO satellites for example, while it also varies depending on the relative positions of Earth and Mars. Table 17 below shows the FSPL between Earth and Mars for various frequencies ranging from 300 MHz to 32 GHz.

Table 17: Free-Space Path Loss at Various Frequencies (adapted from Ho, Golshan and Kliore, 2002).

Free-Space Path Loss (in dB) Distance (km) VHF Band S Band X Band Ka-Band Optical (300 MHz) (3 GHz) (10 GHz) (32 GHz) (~300 THz)

Earth-ISS 400 ~134 ~154 ~165 ~175 ~254

Earth-GEO 36,000 ~173 ~193 ~204 ~214 ~293

Earth- Mars at 55 x 106 ~237 ~257 ~267 ~277 ~357 Opposition

Earth-Mars at 400 x 106 ~254 ~274 ~284 ~294 ~374 Conjunction

Additionally, future missions are expected to become more complex and require more data to be transmitted between the spacecraft and the ground station, as showcased by NASA’s Deep Space Network forecast below (Figure 28). To achieve data rates 10 to 100 times higher than state-of-the-art present radio frequency communications, NASA is investing in optical communications, where data is transmitted using frequencies falling close to the visible part of the spectrum (Campbell, 2017).

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Figure 28: NASA Deep Space Network Capabilities (Hughes, 2017).

One way to mitigate the power losses in free space is to increase the antennas’ gains (Gr and Gt). Figure 29 below illustrates an example where an antenna’s gain is increased by enlarging the antenna. This can be made by adding antenna elements such as in array antennas and thus adding gain. Directly 3D printing these radiating elements can improve the antenna gain in case of no other available option. (Satmarin, 2019). Albeit the possibility of increasing an antenna gain by augmenting its diameter is feasible, three issues affect the design of antennas for spacecrafts; (i) size restrictions due to fairing dimensions of launch vehicle, (ii) vibrations and other mechanical loads during launch, and (iii) antennas exhibit a logarithmic relationship between gain and diameter (i.e., as illustrated in Figure 29, increasing the antenna size by a factor of 8, increases the gain by a factor of 1.6 only).

Figure 29: Relationship between Performance and Antenna Size (Satmarin, 2019).

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The section below will assess the potential to use a 3D printer coupled with assembly robotic arms that will enable the manufacturing of large antennas and reflectors for optimized deep space communications.

3.2.2 Technology This section addresses the communication hurdles discussed in the above section and discusses the feasibility of using a 3D printing technology coupled with assembly robotic arms to improve communication between a crewed spacecraft in deep space and Earth. Such technologies are currently being developed by Made in Space with the Archinaut and by Tethers Unlimited with the SpiderFab. Additionally, Kleos Space and Magna Parva are investing in manufacturing techniques of carbon fiber structures to create antennas and solar panel arrays (Kleos, 2019).

As mentioned in Section 4 of Chapter 1, Made in Space is making progress on its Archinaut technology, which will enable the in-orbit manufacturing and 3D printing of antennas, reflectors, radars, arrays and other structures for direct use in space. The two projects which employ the Archinaut technology are underway; the first 3D printing and in-orbit manufacturing is Dilo, a spacecraft that transforms into a large reflector, while the second is Ulisses, a free-flying robot that manufactures and assembles large structures in space (Made in Space, 2018). In 2017, Made In Space was able to demonstrate its Archinaut technology in a thermal vacuum chamber at NASA Ames Research Center by printing a 32m long beam (Wall, 2017).

Dilo could bring in added-value to a crewed deep space mission. In fact, the reflective elements are stored on-board and only attached to the Dilo itself through 3D printing techniques to create a fully deployed large reflector (Figure 30), thus greatly reducing the required launcher size and dimensions (Made in Space, 2018). As mentioned previously, an increase in the antenna size can mitigate the power losses associated with the free-space path loss.

Figure 30: Archinaut Dilo Spacecraft Attaching its Reflectors (Made in Space, 2018).

Additionally, Harris Corporation, a company specializing in communication systems for the space and defense sector, developed a 3D printing technique that uses titanium to manufacture Fixed-Mesh Reflectors for communication satellites such as one of the Inmarsat’s satellites. Using 3D printing technology, Harris was able to eliminate 3.5 hours of labor production time and reduced assembly errors (Harris, 2016).

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Such aforementioned improvements in 3D printing and assembly technologies could be merged into a single solution. The initial phase will require Fixed-Mesh Reflectors to be 3D printed on-board the crewed spacecraft to Mars. This phase will be followed by a second phase that leverages the Archinaut’s technology to attach and assemble those 3D printed reflectors directly in orbit. As such, a crewed deep space mission will likely benefit from acquiring deep space communication capabilities provided by Dilo.

Other antenna components can also be 3D printed on-board (i.e., customized horn antennas and antenna arrays) by using Swissto12’s technology currently being used for manufacturing of Earth antennas (Swissto12, 2019). Combining the Archinaut technology with Swissto12’s 3D printing can bring in added- value. Eventually, research and development to manufacture such antenna horns and arrays directly in space could enable cost saving in the form of reduced spare component storage requirements, while enabling a higher reliability of communication systems on a spacecraft.

To reduce risk and increase reliability, a redundant communication system will need to be on-board the spacecraft with ability to 3D print replacement parts for Dilo. Risks associated with integrating and not integrating such technologies on-board will be further addressed in Section 7.

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4 Spacecraft Parameters

4.1 Storage Space As the duration of crewed missions increases, demand for critical life components and spare storage will increase accordingly. Currently, the Russian modules Rassvet and Zarya and the Italian module Leonardo MPLM are used for storage on the ISS, with a combined volume of just over 55m3 (International Space Station, 2019). A long-term deep space mission may not have the luxury of this storage space - mass considerations could be expected to restrict the size of the spacecraft, and resupply from earth would be nearly impossible. Along with mass, a saving in storage space would be a major benefit ISM could provide, due to the ability to print on demand from a common feedstock rather than keep spares of multiple distinct parts. Storing liquid or powder bulk material will always be more efficient in space than storing the final products which require special packaging and have specific form and volume.

4.2 Mass One of the greatest barriers to space exploration is launch cost. Launch cost is directly influenced by mass, so any reduction in mass will reduce the cost of a space mission. One way to achieve this is to reduce the mass of spare items taken into orbit by means of additive manufacturing. Owens, et al., (2015) describes how additive manufacturing is able to reduce this mass by, “enabling commonality of material”. The authors quantify the mass of spares and the probability of part failure in order to determine how many times a part will need to be replaced or repaired. They also take into account how much spare weight is carried by those parts that were never replaced and carried over to the next mission. They used these numbers to determine the amount of feedstock required for long duration missions as well as the mass reduction that this can provide.

In a case study on a hypothetical twenty-six month deep space mission, replacing ECLS components, it was determined that the spares mass reduction was at 17% using low precision manufacturing (Owens, et al., 2015). By using high precision manufacturing, the mass was reduced by 35%. A summary of the baseline and mass savings can be found in table 18 below.

Table 18: Mass of spares and reduction by using AM on a twenty-six month deep space mission (Owens, et al., 2015). Manufacturing Baseline Total Mass for Total Mass for Reduction in Mass Precision Mass (t) Spares with AM (t) Feedstock (kg) (%) Low 9.21 7.65 642 17% High 9.21 6.02 909 35%

For subsequent missions beyond the initial flight, the mass required for spares is less, as is the savings using additive manufacturing. The reduction of mass for the second flight is 6.7% for low precision and 13.3% for high precision manufacturing. There is a reduction of mass up to the 9th mission, where savings taper off. These results were based on bringing all spares and feedstock from Earth. When calculating

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Chapter Two: Deep Space Crewed Mission using in-situ resource feedstock, such as from the surface of Mars, the mass savings are increased to 2.20t - a 41% increase in savings over earth based feedstock for low precision manufacturing. For high precision manufacturing with ISRU feedstock, there was a 4.10t mass savings resulting in a 29% increase in mass savings over earth based feedstock (Owens, et al., 2015). The mass saving graphs from the cumulative spares and spare logistics with Earth based and ISRU based feedstock can be seen in figure 31 below.

Figure 31: Mass savings from AM using Earth based and ISRU feedstock (Owens, et al., 2015).

In a comparative analogy, Owens and de Weck (2016) showed that the number of spares in orbit on the ISS is currently over 13,000 kg. The expected average of failures was reported to be only around 450 kg annually (see Figure 4 of Section 1.1). Added to this mass is the estimate of spares on the ground of about 18,000 kg that are ready to fly at any given time. Out of the approximate 31,000 kg in spares, it is estimated that 95% will most likely never be used. However, as these are mission critical spares, they must be in circulation and ready to fly or to be manufactured. 3D printing is a technology adequate for producing spares on demand reducing mass and storage volumes. If only 450 kg of spares are used out of 13,000kg, that leaves 12,000 kg for the weight of the printers itself and 5% margin for bulk material. Additive manufacturing and recycling create a suitable solution for spare parts and specialization while in transit.

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5 TRL Timeline

Figure 32, below, gives an overview of the different Technology Readiness Level (TRL) levels and how they equate to where a technology is in its development lifecycle. To get an idea of the TRLs of the technologies discussed in chapter 2 thus far, they have been outlined below in Table 19. This shows the mission requirements, ISM technologies, and applications of each technology, as well as the TRL based on current research and development.

Figure 32: An explanation of TRL levels (WaybackMachine, 2004).

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Table 19: Technology Readiness Levels of discussed ISM technologies.

Requirement Chapter/Section Discussed Technology Technology Status TRL

Heat Melt Water extraction/ Compactor 2.2: Waste Management structural Developed (terrestrial) 7 (HMC) component build

Printer viability Additive printer Environment demonstrated on ISS. 2.4: Mental Health (Made in Space 9 dividers Product developed 3DP) terrestrially.

Printer viability Recreational Additive printer demonstrated on ISS. models and 2.4: Mental Health (made in space 9 Product developed pieces 3DP) terrestrially.

Integrated plastic Printer viability 1, 3.1: Current Techniques Refabricator recycling and demonstrated on the 8 2.2: Waste Management plastic printing ISS.

Printer viability Air Revitalization Recycle carbon 2.1.2: Atmosphere demonstrated on the 8 system dioxide into oxygen ISS.

Waste water and air moisture Water Recycling 2.1.2: Water Part of ECLS in use on ISS 9 recycling into clean water.

Metal Advance Manufacturing 1, 3.2 - In-Development Integrated metal Component Bot-Assisted Techniques recycling and development prior to full 4 Assembly 2.2 - Waste Management plastic printing assembly (MAMBA)

Fully developed for Thermal Inkjet terrestrial use. Delayed Printing/Fused by regulation. Not yet 3D printing of 2.3: Medical Supplies Deposition developed for space 5 Medicine Modelling application, uses (FDM)/ZipDose conventional 3D printing technologies

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Under development with Communication vacuum thermal test Antenna 3.2: Communication Archinaut successfully passed and 6 Structure and in-space test expected in Assembly 2019

Harris’s 3D printed Communication Technology developed Fixed-Mesh Antenna 3.2: Communication on Earth but for use in 5 Reflectors using Reflector Space Titanium powder

3D printing of Aerosol Jet Proven in terrestrial electronic 3.1: Radiation (Equipment) (electronics) and 5 environment circuitry FIT

3D printing of Aerosol Jet (solar Proven in terrestrial 3.1: Radiation (Equipment) 5 solar cells cells) and VICOSC environment

Automated Made In Space Tested on parabolic assembly of 3.1: Radiation (Equipment) 6 SMM flight components

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6 Challenges

While 3D printing could be revolutionary if applied to space products, it should not be seen as a global solution as there are still multiple challenges to overcome before additive manufacturing can reach its maximum potential.

Before getting into the details of the three main challenges identified, Table 20 shows a SWOT analysis of 3D printing based on the study developed throughout this report. The SWOT analysis has the advantage of synthesizing the strengths and weaknesses of a defined topic with regard to the opportunities and threats generated by its environment. Hence, this analysis is of particular importance to set the basis of the challenges and limitations 3D printing can face.

Table 20: SWOT analysis of 3D printing (McAlister and Wood, 2014).

Strengths Weaknesses

- Reduced design constraints - Limited material variety - Reduced number of parts - Limited structural properties - Efficient use of materials - Cost - Reduced supply chain - Speed and volumes - Negates dedicated tooling - Usability - Reduced labor cost - Printer proliferation - Less barriers to market - Design Issues

Opportunities Threats

- Customized products - Copyright, patents and ethics - Cheap small production runs - Tort law - Physical testing - Frivolous printing - Job creation - Traditional job losses - Manufacturing repatriation - Qualification - End to obsolescence - Manufacturing - Drive to innovation

That said, to take full benefit of the 3D printing and manufacturing capabilities the following key challenges need to be addressed.

6.1 Design Challenges The main challenge coming from the design is that current design tools are not capable of enabling the full capacity of additive manufacturing. In fact, design tools do not include specific features for 3D printing and they often are not compatible with the machine programs which leads current design tools that are not adapted to facilitate additive manufacturing features (Ghidini, 2013).

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Additionally, 3D printers operating in space must be designed to take into consideration the launch environment. As such, a 3D printer launched into space will experience vibration loads, mechanical stresses, acoustic and thermal loads, and must thus be designed to resist those external stresses. When operating in microgravity, 3D printers must be able to operate normally under microgravity constraints. Hence, they should be fitted with active feedstock pumps or pushers for example.

Another challenge related with 3D printing technologies is the need for pre-processing as well as post- processing operations. As such, 3D printed components must be removed from the printer, and polished or ground to meet the desired surface finish, electrical conductivity, and look and feel in the case of medical products for example.

One last challenge needs to be noted as its importance is not negligible: the design rules for 3D printing are not fully established yet (Ghidini, 2013). In other words, if traditional design answers to specific requirements, those are quite different when speaking of 3D printing, especially if this printing is done in space. Table 21 demonstrates those design difficulties for the products discussed previously.

Table 21: ISM Design Challenges. Products Design Challenges

Ensure that recycling input can come in a large variety of forms and Waste Management materials (including metals and electronics), not just pre-used plastic. Systems Include spare parts for the hardware itself since they might not be manufacturable if hardware fails.

High space requirements, high energy demands, complex biological Bio-regenerative Systems interactions, catastrophic failures leading to contamination.

Next generation life support system, which can recycle CO₂ into O₂, has been installed in the US Destiny laboratory. The new system is made to demonstrate the new technology. It can recycle more than Closed Loop Systems 50% CO₂ exhaled by the astronauts. Higher efficiencies are harder to reach, which currently results in significant mass loss in air over the course of a long mission.

Ensuring enough micrometeoroids shielding is provided around the spacecraft to ensure that cryogenic hydrogen or water walls are not Radiation & penetrated. Need to ensure printers are able to print both a high level Micrometeoroids Shielding of detail and large structures, depending on whether printing a full solar array or sensitive microcircuitry. Polyethylene imposes design challenges due to its operating temperatures for example

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Developing the design to work in microgravity. As the full capabilities of the technology have not yet been matured to operate in microgravity, the design of such a process will need much consideration. Some of the current techniques are based on powder Medical Supplies or liquid bulk materials which under microgravity can behave differently than expected on Earth. This can affect product quality but also human health. Yet, the challenge is reduced by the fact the many of the printing techniques are well established 3D printing techniques, and specific solutions can be found.

Design is constrained by the 3D printer size, which limits the volume Communication (Antennas of products that can be manufactured. and Reflectors) Additionally, low mass material are usually favored on space missions and will put constraints on the design of antenna and reflectors.

Generic designs are already freely available for the products in question however adjustments may be required for in space usage Mental Health Products such as preventing free floating components which could create hazards.

6.2 Manufacturing Challenges Accuracy, reproducibility and reliability have to be guaranteed from raw material to the end product through the manufacturing process. However, currently the raw material procurement is not fully controlled which has an impact on the manufacture. For instance, the characteristics of the powder can change from one furnisher to another, the traceability of the latter is difficult and the same applies for its procurement.

Regarding the technical part of the 3D printers and their process stability, it has been demonstrated that two identical machines from the same manufacturer produce slightly different output (Ghidini, 2013). This could potentially create difficulties if two identical pieces are required or if one piece is of poorer quality. Those manufacturing challenges are illustrated in Table 22.

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Table 22: ISM Manufacturing Challenges. Products Manufacturing Challenges

Develop installation, testing, and maintenance techniques for the Waste Management hardware to account for mission duration; Confirm manufacturing times Systems and procedural list are both small enough to lower the risk of user mistakes.

Bio-regenerative Implementation from prototypes to large scale systems. Systems

Ensure sufficient redundancy in all closed loops to minimize risk. Address degradation of the plastic during the recycling process and ensure Closed Loop Systems process control. The integrity of the printing process relies on the feedstock having stable chemical, mechanical, and geometric properties.

Sterilization of the equipment, in microgravity, it is extremely difficult to maintain clean environments; High grade 3D printing machines especially ones that are used for metals and electronics can be quite large and require consideration in mass and volume budgets; Complete automation Medical Supplies of the process is not viable in the near future. Pre- and post-fabrication will require human intervention; In some cases the medical treatment is an emergency, the technology manufacturing time constants are not short enough yet. Thus some supplies will have to be pre-made and not manufactured on demand.

Communication Ensuring correct alignment of antenna reflectors when positioned on the (Antennas and structure (i.e. Dilo); Ensuring reflectors can be easily moved if not properly Reflectors) aligned; 3D printing of metals in microgravity is still under-development.

There are large mass requirements to launch sufficient cryogenic liquid Radiation & hydrogen for shielding. The liquid hydrogen installation into the spacecraft Micrometeoroids will also need to be handled carefully and may increase risk. Polyethylene Shielding imposes certain manufacturing challenges regarding hazardous fumes and thermal control needs.

Utilizing terrestrial manufacturing information available for the designs in question, manufacturing time can range from two hours twenty minutes Mental Health through to eight hours (Yeggi, 2019). This information must be prefaced Products with a caveat however as they have, as of yet, not been tested in situ microgravity tests. Challenges may be identified once this testing occurs.

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6.3 Qualification and Standardization Challenges The main difficulty regarding the qualification and standardization of 3D printed products is that the classical qualification methods do not apply for additive manufacturing because the material evaluation samples are not always representative of the printed object, the polyamide (PA) requirements are not established yet and neither are the process verification methodologies (Ghidini, 2013). This is a huge gap in the additive manufacturing process because the safety standards cannot be reached for lack of consistency between the different qualifications.

In addition, the compatibility with other manufacturing processes needs to be validated especially in regards of space requirements. This includes interface machining, surface finishing, assembling and joining, and thermal treatments (Ghidini, 2013).

These qualification and standardization challenges are keeping additive manufacturing from being used on a global scale. Currently, even the liability chain is not clear, and the different types of manufacture make it almost impossible to have harmonized products. This lack of qualification is shown in Table 23.

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Table 23: ISM Qualification and Standardization Challenges. Products Qualification and Standardization Challenges

Waste Management Standardize elements of waste, such as food/equipment packaging in Systems terms of material, size and mass, for use in recycling/production devices.

Hygiene qualifications are a major shortfall as is processing of products Bio-regenerative (algae and microorganisms). Standardized production systems Systems (hydroponic systems, bioreactors).

Qualify Verification against Feedstock Specifications; Standardization of feedstock, process, acceptance procedures and life cycle management; Closed Loop Systems Standardization of key system components with high expected failure rates.

As the increased radiation exposure in space has been recorded to reduce the shelf life of certain drugs (Du, et al., 2011). Manufacturing in space might not produce drugs with long enough shelf lives to support a 3 year mission. The effects of radiation on the active ingredient need to Medical Supplies be further examined as well as how the active ingredient is affected before and after the manufacturing process. Also, qualification of the drugs produced will be a challenge as it will be difficulty to verify that the printed dosage is correct, especially for stronger drugs.

Due to the high variability in finished products, the quality of the Communication reflectors and other antenna parts will impact the antenna gain. This will (Antennas and reduce the antenna’s ability to efficiently communicate with the ground Reflectors) segment, thus posing risks to the mission.

The suggested shielding is only TRL 6 so there are significant qualification challenges to meet crew requirements for effective radiation exposure limits. Microcircuitry and solar cell printing technology is currently only Radiation & TRL 5 and would need a further qualification to be suitable for use in a Micrometeoroids microgravity environment. The variety and complexity of Shielding microelectronics in spacecraft subsystems may make standardization extremely difficult, if not impossible, and so printers would need to be able to custom-print a highly variable set of circuits.

Microgravity qualification of terrestrially printed products has yet to occur. Verification and Competence must be proven before certification Mental Health Products by Astronauts (AMSC, 2018). Qualification of the technology required is already in the process via ISS testing.

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7 Risks

Installing and operating 3D printers and other in-orbit manufacturing technologies on a spacecraft does not come without risks. Those risks can be stemming from a multitude of factors such as hardware design lifecycle, human errors, software issues and thermal stresses to name a few.

Additionally, some risks arise from the lack of having 3D printers and in-orbit manufacturing techniques. Those risks are described in Table 24 below.

Table 24: Risks, Ratings, and Mitigation strategies. Risk # Risk Causes Impact Mitigation Rating Bio-regenerative Systems/ Bioreactor for Food Production - Perform constant - Pathogens maintenance - Cleanup - Contamination - Disinfect surfaces requirement of spacecraft - Develop and follow Biological - Contamination of 1 by biological 1C proper hygiene Contamination spacecraft by material protocols biological material - Equipment - Integrate - Crew illness failure automatic sensors for upkeep

- Contaminant leaks - Perform constant - Environmental maintenance contamination - Provide training to - Short circuit - Fire hazard repair systems - High energy - Crop damage or loss - 3D print 2 System Failure radiation - Food contamination 2B replacement parts - Human error - Loss or partial loss - Store dry - Wear and tear of oxygen supply emergency food - Loss or partial loss - Store emergency of carbon dioxide O2 onboard removal system

3D Printer using Animal Proteins

- Freeze animal cells in shielded - High energy Cell Culture containers radiation Does Not - Loss or partial loss - Develop and follow 3 - Human error 3B Survive in of food source protocols - Long-term Deep Space - Introduce microgravity redundant systems (e.g., dry food)

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Risk # Risk Causes Impact Mitigation Rating Heat Melt Compactor - High energy - Add additional radiation - Spacecraft insulation layer Solid Waste 4 - Human error contamination 3B - Perform regular Leak - Wear and tear - Crew illness maintenance - Short circuit - 3D print spares

- High energy - Perform regular - Potential solid waste radiation maintenance leak 5 System Failure - Human error 2A - 3D print spares - Accumulation of - Short circuit - Jettison waste into solid waste - Wear and tear deep space

Refabricator

- Perform regular Hazardous - Human error - Crew illness maintenance 6 Fumes’ - Wear and tear - Spacecraft 3A - Use non-hazardous Leakage - Short circuit contamination plastics

- Inability to - Wear and tear repurpose plastic - Perform regular - Human error parts or print new maintenance 7 System Failure 4B - Short circuit spares and tools - Include redundant - Radiation - Potential fumes systems onboard leakage

- Human error - Install non- Improper - Risk of other - Software destructive testing Production of equipment failure 8 failure 3C equipment Plastic Part or - Wasted system - Raw material onboard Spare power inconsistency

- Improper - Proper planning planning and and assessment in overuse of bulk analog missions Shortage in - Inability to produce 9 materials 2C - Development of Bulk Material in the long run - Failure of ISRU technologies recycling and recycling systems

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Risk # Risk Causes Impact Mitigation Rating

3D Printing Technologies for Medicine & Medical Products

- Radiation - Inability to - Expiry date of - Freeze emergency Loss in Active effectively treat active ingredient active ingredients 10 Ingredients’ crew 4D reached in shielded Effectiveness - Risks of depression - Bacteria containers - Risks of cancer mutations

- Store a small amount of critical medication on board - Inability to print - Ensure all parts of required drugs or the drug 3D printer Failure of medical supplies/ - Component can be replaced Equipment & products failures and produced by 11 Over Reliance - Inability to print 3A - Software failures other part on 3D Printers recreational - Human error production Operability products, leading to techniques on frustration and board possibly monotony - Usage of 3D printed components for the printers itself

- Account for control samples of known drugs to - Incorrect - Incorrect drugs validate the Improper production administered process against 12 Production of instructions, 4C - Possible damage to - Perform tests to Drug (dosage) component/soft crew health routinely check ware failure production dosages are correct

- Lack of research - Inability to produce - Invest in possible Lack of In-space and drugs while in space drug production Production development of 13 - Possibility of running 5C technologies and Processes product out of needed adapt to space Developed - Rushed mission medication production planning

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Risk # Risk Causes Impact Mitigation Rating

3D Printing Technologies for Medicine, Medical Products and Psychological Support

- Protection of bulk materials compartments Bulk Material - Breach in - Health hazard (e.g., - Isolation of Spread in printers chamber inhaling particles, 14 5B printing modules Spacecraft - Printing residues eye damage, and - Atmosphere Atmosphere - Post-preparation skin irritation) evacuation, filtering, and ventilation

- Good communication - Long delays - Inability to produce contingencies Communication 15 - Relatively large required specific 1C having pre of CAD Files files models prepared files onboard for most needs

- Improper - Proper planning planning and and assessment in overuse of bulk Shortage in - Inability to produce analog missions 16 materials 2C Bulk Material in the long run - Development of - Failure of ISRU technologies recycling and recycling systems

- Train astronauts in 3D printing and - Lack of deep - Mistakes in medical Insufficient expertise in 3D operations of 17 3B procedures Experience printing of medical tools and - Experiment on medical drugs printers analog missions and ISS

Damage to - Recreational Spacecraft game products - Develop and Critical Systems floating away - Potential mission implement 18 and getting stuck 3A failure guidelines and in spacecraft’s protocols critical systems

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Risk # Risk Causes Impact Mitigation Rating

Manufacturing Technologies for Radiation Shielding & Electronics’ Repair

- Conduct design/safety Leak or failure reviews at all of Cryogenic - Crew danger milestones and run Liquid - Insufficient - Potential mission lab tests with the Hydrogen design and 19 failure 5B intended design system, safety - Increased risk of - Perform potentially parameters cancer experimental tests causing tank using the liquid explosions hydrogen wall on the ISS

- Inability to print personalized clothing with - Perform regular - Wear and tear Failure of embedded maintenance - Human error 20 Polyethylene polyethylene for 3B - Include redundant - Short circuit 3D Printer radiation protection systems onboard - Radiation - Increased risk of cancer

- Perform regular maintenance - Radiation - Include redundant - Wear and tear - Inability to 3D print systems onboard Failure of - Human error electronic - Develop a safe 21 Electronics’ 3D - Short circuit replacements 5B workbench for Printer - Over-reliance on - Cascade of other manually creating 3D printing system failures electronics and operability train astronauts accordingly

- Radiation - Inability to 3D print - Wear and tear - Include redundant Failure of Solar solar arrays - Human error systems onboard Arrays 3D - Decreased power 22 - Short circuit 4B - Include emergency Printer and generation - Over-reliance on nuclear power Assembler depending on failure 3D printing generator date operability

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Risk # Risk Causes Impact Mitigation Rating

Manufacturing Technologies for Communications

- Inability to manufacture large - Redundant - Components antenna with a high communication Failure of 3D failure due to data rate, leading to systems Printer and wear and tear restrictions on data - Storage of some 23 Assembler of 4B or radiation transfer rate and critical Antenna and - Software potential adverse components with a Reflectors failure effects on crew high likelihood of systems and mental failing health

- Perform EVA to Misalignment - Decreased antenna - Control system realign reflectors of Reflectors efficiency with the failure - Design reflectors 24 or Defective potential 3C - Laser scanning for easy 3D Printed introduction of system failure replacement Reflectors noise procedures

- Position robotic arms sufficiently far away from critical external components Malfunction of - Damage of - Hardware - Include Robotic Arms spacecraft external failure “shutdown” code 25 during components 5A - Software in the software Assembly of - Potential piercing of failure when abnormal Antenna hull behaviors are detected and directly stop robotic arms’ operations

- Increase - Cost or - Inability to investments in in- Lack of 3D schedule issues manufacture higher space Printer and/ or during the 26 gain antennas in 4A manufacturing and Assembler On- technology space, thus limiting assembly of board development the data rate antenna and process reflectors

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Figure 33: Risk matrix associated with proposed ISM technologies.

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8 Financial Considerations

This section aims to provide a basis to estimate the future demand for in-space manufacturing capabilities in deep space crewed missions as well as illustrate cost savings through a case study on spares. As such, this section will lay out the governmental agencies and private corporations’ plans to perform deep space crewed missions, thus providing an understanding of the number of deep space trips expected to occur by 2050 (governmental and private spacecraft).

As of 2019, only NASA and SpaceX have mentioned clear plans to eventually send humans to Mars, albeit the fact that NASA is first considering using the Moon as a pit-stop (Dunbar, 2018), while SpaceX is expecting to send the first uncrewed Big Falcon Rocket to Mars by 2022 (Foust, 2018). Other countries such as Russia have mentioned their willingness to send crewed missions to Mars, first starting with robotic missions at the next launch window (Torossian, 2018). Additionally, Blue Origin is also a strong player in the field of crewed space-flights, although focusing at present more on space tourism (Upson, 2019).

Figure 34: NASA’s forecasted available budget and costs of human spaceflight program (National Research Council, 2014b).

According to the National Academy of Science, NASA’s inflation adjusted budget for human spaceflight is expected to reach USD ~16 B by 2040 (National Research Council, 2014b), as illustrated in Figure 34. The ISS could potentially be decommissioned in 2024, thus allowing NASA’s budget to be redirected towards other projects (Klotz, 2017). It can be assumed that the previously allocated ISS finances, as shown in figure 34, will be transferred to new projects such as the human deep space exploration missions to Mars

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8.1 Case Study - Plastic Spares For the sake and relevance of this section, the following overall assumptions apply: - The total time required for the mission will be three years (as agreed upon previously) - The mission will feature a crew of seven astronauts (as agreed upon previously) - The deep space mission will be to travel to Mars, orbit for a few months and then come back - The cost of launching a payload to Mars will be assumed to range from USD 45,000 per kg to USD 63,000 per kg, assuming SpaceX’s Falcon Heavy can carry around three to four tonnes of payload to Mars at a fixed price of USD 135 Million and SpaceX’s current price for launching cargo to the ISS respectively (De Selding, 2016; NASA Inspector General, 2018). This range is used as a sensitivity analysis. - Without ISM capabilities, the mass of onboard stock of spares needed on a spacecraft to Mars is assumed to be 60% of the onboard ISS mass of stock of spares plus three times the annual ISS resupply of stock (Refer to table 26) - With ISM capabilities, which include recycling, the mass of onboard stock of spares needed on a spacecraft to Mars is assumed to be equal to three times to mass of expected annual ISS failures in addition to one tonne of raw materials (Refer to table 27) - Due to the limited information regarding the split of cargo launched to the ISS (e.g., electronics, plastic tools, metal parts, ceramic components), it is assumed that 30% of the cargo launched to the ISS are plastic components.

As described in Figure 35, in 2009 NASA developed the Design Reference Architecture (DRA) 5.0 for a human landing on Mars. According to Foust (2015), NASA is not considering updating this DRA but with current commercial and renewed interests in Mars, DRA 6.0 may become a necessity. 3D printing and in- space manufacturing techniques can help reduce the need to launch cargo to Mars twenty six months prior to the crew launch as illustrated in DRA 5.0.

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Figure 35: NASA Design Review Architecture 5.0 for Human Landing on Mars (Drake, 2009).

Table 25: Information regarding ISS Spares (Owens and de Weck, 2016).

Inputs Value Comments

Mass of Spares Currently Stored Onboard 13,170 kg (Owens and de Weck, 2016) the ISS

Mass of Spares Launched to the ISS per Year 3,190 kg (Owens and de Weck, 2016)

Mass of Spare Failures on the ISS 450 kg (Owens and de Weck, 2016)

Table 26: Mass and Costs of Plastic Spares Required on a Spacecraft without ISM Capabilities.

Assumption & Calculations Value Comments

Assuming 60% of 13,170 kg plus 3 x 3,190 kg Mass of Spares Required on Spacecraft to 17,472 kg (3 years worth of annual resupplies to ISS) Mars without ISM Capabilities (Owens and de Weck, 2016)

Mass of Plastic Spares Required on 5,241 kg Assuming 30% of 17,472 kg for plastic parts Spacecraft to Mars without ISM Capabilities

Cost of Launching the Mass of Plastic Spares USD 236 - Assuming launch costs to Mars varying Required on Spacecraft to Mars without ISM 330 between USD 45,000 and 63,000 per kg (De Capabilities Million Selding, 2016; NASA Inspector General, 2018)

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Table 27: Mass and Costs of Plastic Spares Required on a Spacecraft with ISM Capabilities.

Assumptions & Calculations Value Comments

Mass of Spares Required on Spacecraft to Assuming three times the mass of spare Mars with ISM Capabilities (including 1,620 kg failures on the ISS plus 20% margin as emergency raw material) emergency raw material

Mass of Plastic Spares Required on Spacecraft to Mars with ISM Capabilities 486 kg Assuming 30% of 1,620 kg for plastic parts (including emergency raw material)

Assuming that a trip to Mars will experience similar failure rates as the ISS but over a Cost of Launching the Mass of Plastic Spares USD 22 - three years period. Assuming launch costs to Required on Spacecraft to Mars with ISM 30 Million Mars varying between USD 45,000 and Capabilities 63,000 per kg (De Selding, 2016; NASA Inspector General, 2018)

Table 28: Mass and Costs of Plastic ISM Equipment Required on a Spacecraft.

Assumptions & Calculations Value Comments

The AMF from Made in Space has a mass of Mass of Additive Manufacturing Facility on 100 kg 45 kg. It has been assumed that upgraded Spacecraft to Mars equipment will be needed

Assuming launch costs to Mars varying USD 4.5 - Cost of Launching Upgraded AMF to Mars between USD 45,000 and 63,000 per kg (De 6.3 Million Selding, 2016; NASA Inspector General, 2018)

Mass of Refabricator from TUI 1,000 kg Assumption

USD 45 - (De Selding, 2016; NASA Inspector General, Cost of Launching Refabricator to Mars 63 Million 2018)

Based on table 26, the total cost of launching all the mass required to support a three year mission to Mars in terms of plastic spare parts and components, without the ISM capabilities onboard, is expected to range between USD 236 to 330 Million. Comparatively, based on tables 27 and 28, a spacecraft travelling to Mars with plastics’ ISM capabilities onboard will need to account for the following costs: - Cost of Launching the Mass of Plastic Spares Required on Spacecraft to Mars, including emergency raw material (USD 22 - 30 Million) - Cost of Launching the Upgraded AMF (USD 4.5 - 6.3 Million) - Cost of Launching the Refabricator (USD 45 - 63 Million) - Cost of Additional Power Requirements (USD 2 Million, assuming 1,000 W power requirements provided by GaAs solar cells)

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- Cost of Thermal Requirements (Assumed as a percentage of power requirements costs) - Developmental Costs of AMF and Refabricator (USD 2 Million for Made in Space, (NASA SBIR/STTR, 2019) 2.5 Million for Tethers Unlimited (Iftikhar, 2019) - Manufacturing Costs of one AMF and one Refabricator (USD 1 Million, assumed as 30% of developmental costs)

As such, a spacecraft with ISM capabilities on a three years journey to Mars will require: - USD 75 - 110 Million in launch costs and operational costs (Assuming ~5% margin of errors) - USD 4 Million in one-time capital expenditure (Developmental and manufacturing costs)

Since the equipment will be used for at least three years, then it is fair to assume that the capital expenditure can be spread over three years. As such, the developmental and manufacturing costs account for ~1.3 Million per year. This cost is rather negligible when compared to the launch and operational costs mentioned previously. Based on the above calculations, it can be inferred that in-space plastic recycling and 3D printing on a spacecraft travelling for three years can enable up to USD 200 million in cost savings over a period of three years. Other ISM capabilities discussed throughout the report such as in-space drug production, and metal, ceramics, and textile ISM can also enable cost savings through a reduction in the overall mass that needs to be launched into deep space.

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9 Political Considerations

While the use of public private partnerships shall be considered in the following section from the perspective of a private entity, they have been rejected due to their lack of reliability. Instead, the role of the contractor for different space agencies will be focused on and the policies of these agencies will be studied and classified to allow selection of the best partners with which to develop a crewed deep space mission. Among these space agencies, the Israeli space agency was considered but has been excluded due to its tight links to NASA.

9.1 Public Private Partnerships The public-private partnership (PPP) is a form of financing through which a public authority uses private providers to finance and manage public equipment. In return, the private partner receives a payment from the public party (Klijn and Teisman, 2002). In the space sector, PPPs have developed mainly because of government budgetary constraints, the decrease of government-controlled industries and economies, and exponential growth in the private sector.

However, PPPs do have three main cons that outweigh the advantages that this solution could bring: - Limited benefits for cost and management efficiency; - PPPs are funded by the States which may use them to hide their debts; - Due to the aforementioned cons, delays are frequently experienced when conducting a project under a PPP (Lampropoulos, 2018).

As the drawbacks of PPPs are significant in nature, one solution remains to allow engagement in this market: getting a contractor status with a space agency. In order to establish likely partners, a grading of the main global space agencies has been developed in the section below based on their policies regarding deep crewed space exploration.

9.2 Agencies Grading 9.2.1 Big Partners National Aeronautics and Space Administration - NASA The President of the United States of America has recently taken a number of steps to update old policies and maintain the U.S.’s competitive advantage as a leader in the industry. A significant proportion of their budget is spent on the development of new technologies to enable deep space human spaceflight. The allocated budget is due to fluctuate somewhat in the coming years but overall, will still remain one of the largest proportions of NASA’s budget (NASA, 2019d).

The signing of space policy directive - 1 instructed NASA to focus on returning astronauts to the Moon and send humans to Mars. This memorandum specifically focused the directive to these specific goals but most importantly, included the wording “commercial and international partners” (The White House, 2017). This highlights the U.S.’s awareness of the difficulties in human spaceflight and how those difficulties are more easily overcome with assistance from commercial and international partners.

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Partnering with commercial companies is evident today with the emergence of commercial crew vehicles. SpaceX and Boeing are scheduled to test their crew vehicles this year. NASA partnering with these companies allows for new innovative solutions to arise and also importantly, provide cost-effective solutions to send a crew into orbit. NASA is not only focusing on industry partnerships for launch vehicles but also for in-flight technologies. NASA has teamed up with final frontier design to develop a new intravehicular activity (IVA) space suit which is lightweight, inexpensive, and reliable (NASA, 2018b). NASA policy to work with these companies is clearly benefiting them in order to quickly develop their human space flight ability.

NASA’s history of international cooperation has served them well for human spaceflight and it is understandable as to why they continue with this policy. Today, NASA is actively partnered with ESA, Roscosmos, JAXA, and the CSA on the ISS. Covering the cost of the development and maintenance of the ISS was something that could not be done by one agency alone but was possible with collaboration. Moving forward with its human space flight capability, NASA has partnered with the ESA to develop the Orion Multi-Purpose Crew Vehicle (Orion MPCV) with ESA leading on the development of the service module (ESA, 2015). Again, this project enables NASA to spread the costs while improving the development of deep space Orion MPCV.

NASA currently has three major milestones on their way to deep space human space flight. The first being the development of the Orion Multi-Purpose Crew Vehicle (Orion MPCV). Orion has the capacity to carry up to three crew members for over 21 days. NASA will also have to complete the Space Launch System (SLS). This is a large launch vehicle capable of sending Orion into deep space (NASA, 2019e). Finally, NASA aims to develop the Gateway. The Gateway’s goal is a sustained presence around and on the Moon and to develop and deploy critical infrastructure required for operations on the lunar surface and at other deep space destinations” (NASA Advisory Council, 2018). It will act as a proving ground for later Mars missions and will enable a human presence in cislunar space, cementing NASA’s human presence in deep space.

European Space Agency - ESA ESA has had a strong presence in human space flight and aims to position itself at the edge of human spaceflight capabilities (ESA, 2019). ESA’s rationale behind its focus on human spaceflight and exploration is due to the fact that it aids the socio political goals in the vision of European identity and human spaceflight and exploration are important symbols of space to the public (ESA, 2007).

ESA wants to be an active agent when it comes to missions beyond LEO (BLEO). It has the goal of being a key partner of NASA for BLEO missions. Apart from having previous positive partnerships with NASA, ESA has partnered with NASA for the development of the service module of the Orion MPCV capsule. This was a great decision from a human space exploration policy perspective as it provides ESA with the capability to send crew on the Orion capsule to BLEO. ESA currently has no crew launch capability and no plans for the development of one. ESA also has plans to get involved in NASA’s deep space gateway (DSG) mission. It has a number of technologies such as the European System Providing Refueling, Infrastructure and Telecommunications (ESPRIT) (ESA, 2017).

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ESA also is exploring the possibility of partnering with the Chinese National Space Agency (CNSA) on the Chinese crewed space station. ESA would expand its possibilities to conduct scientific research in orbit as well as expanding the market for European spaceflight products (ESA, 2017).

The development of in space manufacturing to enable crewed deep space exploration, would help ESA on their path towards human BLEO missions. An additional and real benefit ESA could see from the development of these technologies in Europe is the spin-offs and economic advantages that come with them. As previously mentioned, ESA aims to promote growth within Europe through the space sector and this would be another avenue to achieve this.

China National Space Administration - CNSA China’s space policy is led by China’s five-year national plan. In this plan, China has a main focus on manned spaceships, space stations, lunar and Mars exploration (CCPA, 2016).

China Manned Space Program China's manned space mission is mainly dominated by the China Manned Space Program (CMSE). CMSE has a "Three-step Strategy" of development： - To launch a crewed spaceship, build up primarily integrated experimental manned spacecraft engineering, and carry out space application experiments - To make technology breakthroughs in Extravehicular Activities (EVA) as well as space rendezvous and docking of manned spaceships and spacecraft, launch a space lab, and provide a solution for space application of a certain scale with crew on a short-term basis - To establish a space station and provide a solution for space application of larger scale with crew on a long-term basis (CMSE, 2019)

CMSE three current missions of which two are of particular interest in regards of deep space crewed mission: 1. Tiangong II Tiangong II is a space laboratory, also can be described as crewed spaceflight vehicle designed for carrying out space experimental activities. It is the prototype of the space station which means it's smaller than the space station in scale. The major tasks include making breakthroughs on spaceflight vehicles’ space rendezvous and docking and assembly control technologies; breakthroughs on key technologies relating to crew’ mid-term space mission, long-term auto flight of space vehicles, key technologies such as regenerative life support systems and cargo spaceship replenishment and preliminary investigation of key technologies relating to space station construction (CMSE, 2019). 2. Unnamed crewed Space Station This Space Station System is comprised of the Core Capsule, Experiment Capsule I and Experiment Capsule II, with the aim of building a reliable operating space station, and providing long-term support for the onboard healthy living for the crew (CMSE, 2019). Roscosmos The Russian space program has suffered from poor exchange rates which can be seen in its most recent 10-year program. The 2016 – 2025 budget ($20.5 billion) is less than half of the last decades budget ($56.4

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Chapter Two: Deep Space Crewed Mission billion). With this said, Russia is still aiming to keep a human presence in LEO with additional modules planned for the ISS which can become independent stations.

The Kremlin still promises to complete the assembly of the Russian segment of the International Space Station, which has remained unfinished for nearly two decades. According to this plan, a total of three new modules were planned to join the ISS: the Multi-purpose Laboratory Module (MLM); the Node Module (UM); and a new-generation laboratory and power supply facility dubbed NEM-1. These components were supposed to be sent in 2017, the latest Russian plan for the assembly of the ISS, set the delivery of the UM to the Russian Segment of the outpost for November 2019 (Zak, 2016).

Roscosmos had ambitious plans to build a giant super-heavy rocket, which would enable Russia to land its cosmonauts on the Moon by the end of the 2020s and begin setting up a permanent base there. But both the government officials and Roscosmos stressed that the first priority for the program will be communication and broadcasting satellites for now. Also, according to the approved strategy, Roscosmos still remains committed to shifting human space launches from Baikonur in Kazakhstan, to the new spaceport in Vostochny in the Russian Far East. This would need a new launch pad and rocket. The new facility is promised to be ready in 2021, and thus a new generation of spacecraft is needed (Zak, 2016).

Roscosmos promised to launch the uncrewed prototype of the Soyuz replacement in 2021 and to send the first crew to the ISS aboard the new ship in 2023. The Moon landing still remains the strategic goal of the Russian human space flight program (Zak, 2016).

9.2.2 Future Players JAXA JAXA has three policy objectives: ensure space security, promote the use of civil space, maintain and strengthen the science and technology industrial base (National Space Policy Secretariat, 2017).

Although JAXA has no crewed launch capabilities and no plans to develop any, it currently has 10 astronauts and a strong presence when it comes to human space flight. Like ESA, JAXA is one of the five members of the ISS with their own ‘Kibo’ module for scientific research. However, JAXA’s aims for human spaceflight are currently to conduct research in a microgravity environment. They have recently met with NASA to share their views on space exploration beyond LEO but have yet to make any solid agreements to enable them to travel beyond LEO (JAXA, 2018).

ISRO On November 7, 2006, the Indian Space Agency (ISRO) approved India’s first manned space mission. On July 2018, ISRO successfully conducted the first flight test of the "Rocket Escape System" at the Satish Dhawan Space Centre (ISRO, 2018). At the end of 2018, ISRO announced three Indian astronauts will be sent to space by 2021, as part of India's ambitious Gaganyaan project. The Indian government also allocating 100 billion rupees ($1.43bn) for this mission (Phys.org, 2019).

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Iranian Space Agency Iran’s aim is to send an Iranian crew to space within eight years. This goal was put forward by the Iranian Aerospace Research Institute (member of the Iranian Space Research Center), more specifically the aim is to send astronauts to sub-orbital space in collaboration with a private Russian company (The Straits Times, 2017).

While Iran is not ready yet to send humans to space, its space program is promising and its recent launch achievements put the country as a potential future space faring nation. Iran’s ambitions are clear and it would be unreasonable to ignore them.

9.2.3 Recommendations

Table 29: Recommendations for working with agencies. Policy Policy Capacity to send Political and Recommend includes includes Deep humans into Economic partnership crewed Space crewed deep space stability 1 - Yes missions missions within 30 years 2 - Potentially 3 - No

NASA Yes Yes Yes Yes 1

ESA Yes Yes Yes Yes 1

CNSA Yes Yes Yes Yes 1

ROSCOSMOS Yes Yes Yes No (Economical) 2

JAXA Yes No No Yes 2

ISRO Yes No No Yes 2

Iranian Space Yes No No No (Political) 3 Agency

Table 29 summarizes the agencies’ policies from the previous sections, outlines how the policies are in line with deep space human spaceflight, and quantifies their suitability for a partnership focused on deep space exploration.

Some key features to note are that Roscosmos is currently economically unstable, as mentioned in Section 9.2.1 of Chapter 2. The Iranian Space Agency can be considered to be politically unstable due to the current threat of conflict and concerns around nuclear arms (The Washington Times, 2019).

NASA, ESA, and CNSA are all recommended for partnering with for the purpose of deep space exploration due to their capabilities (both now and in the future), their policy, and their stability. It is highly likely that all three will have deep space human mission capability within the next thirty years. Roscosmos, JAXA,

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Chapter Two: Deep Space Crewed Mission and ISRO are all listed as potential partnerships as they all have crewed missions included in their missions statements but either lack current plans and/or capability to carry out deep space human missions or are subject to economic instability. The Iranian Space Agency has crewed missions plans however is not recommended to partner with due to a lack of future plans and regional instability.

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10 Legal Implications

10.1 Legal framework This section would not be relevant without a defined framework, hence for the sake of consistency, the following bases shall be laid: - The point of view is from a private entity; - Based in Luxembourg; - Working as a contractor for governmental space agencies.

In regards to the mission, space law is not relevant since the commercialization of space will not be addressed and nor will weapons will be manufactured. Therefore, the mission in question falls within the framework of European laws as the company is headquartered in Luxembourg.

10.2 General considerations The general considerations usually include the facility registration, the bandwidth and the orbit allocation. However, with regards to the framework foundation expressed at the beginning of this chapter, the private entity shall work for space agencies as a contractor meaning that those considerations shall require assessment only by the latter since only the 3D printer(s), and no spacecraft of any kind, would be provided.

10.3 Intellectual and Industrial property issues 10.3.1 Intellectual property Intellectual property law is a branch of general law that includes all the rules applicable to intellectual or intangible creations. Those are part of what can be assessed as: "intangible property". Moving forward, 3D printing techniques means it is now possible to duplicate any object. Users could then, theoretically, copy anything without the authorization of the intellectual property rights’ owner of this object.

Nevertheless, it is not in the scope of the mission to reproduce any object that would fall under intellectual property protections. Indeed, the tools, the parts or even the medicine manufactured are protected by the industrial property law.

10.3.2 Industrial property law Industrial property allows the protection of technical creations; mainly patents, ornamental creations (drawings & models) and distinctive brand signs.

Regarding that particular legal framework, it is in the scope of the mission to print tools or part of the spacecraft that could be missing or could break. In this case, the patent of said part would be required. In fact, a patent is a protection granted by the government to reward an inventor and the fruits of their ingenuity. A patent makes it possible to obtain a monopoly, or in other words absolute control, on an

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Chapter Two: Deep Space Crewed Mission invention. That said, to avoid any legal issue, it will be fundamental to be sure to obtain the patent before repairing or creating any parts, tools or medicine otherwise the work done will be considered as counterfeiting.

Nevertheless, it must be noted that copyright and licensing work both ways. Indeed, if the private entity aims to create and produce original models for 3D printing, the question of whether or not they want the models to be available to others or not should be raised. And if not, a patent will be needed in order to secure the copyright (Kuliś, 2017).

10.3 Goods or services provider? In order to qualify the mission and thus the applicable law, a distinction between being a provider of goods or services must be made.

10.3.1 The difference between the two notions On the one hand, goods are tangible. They consist of products that can be acquired for use or consumption. Depending on the nature of the good or product, it can be consumed from the first use (e.g. a chocolate bar or a soft drink) or can be used more than once, when the product does not lose its original characteristics (e.g. a pen or shoes).

On the other hand, services are intangible. They are actions which may require special skills or resources provided by a third party. When paying for a service, we do not become the owner of the service, only the result of the action provided by the service provider (e.g. a haircut) or the right to service (e.g. legal advice from a lawyer, a room in a hotel).

10.3.2 Manufacturing in orbit only implies providing goods Providing one or multiple 3D printers for a crewed deep space mission only implies to provide goods for said mission. In fact, the crew would only use the printer to create either tools, food or even medicine which does not imply any particular transfer of know-how or capacity coming from the private company. However, the latter binds itself to provide the goods wanted which brings the liability question: to what extent the company could be responsible in case of a failure?

10.4 3D printing and liability: Tort law 10.4.1 Tort law Tort law or civil liability law is a branch of law that governs the conditions under which a victim can obtain compensation for his/her prejudice. In other words, for each harm there is a reparation of some kind.

In tort law, there is a branch that is of particular importance for the mission statement: the liability for defective products’ law. This is recognized by the European Directive on liability for defective products (85/374/EEC), under which any producer of a defective movable must make good, the damage caused

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(Directive 85/374/EEC). As stated within the submitted framework, the proposed company is headquartered in Luxembourg, thus it is submitted to European law and this Directive applies.

The responsibility of the manufacturer rests also on the seller of a good’s responsibility. Under this legal framework, the manufacturer is liable for any defective material or, more generally, for a defect which makes the goods unsuitable for the intended use. Obviously, the defect must exist at the time of the sale, be unknown to the purchaser on that date and present an issue of note. Ignorance of the defect by the manufacturer does not affect the liability of the latter under the quality guarantee.

Regarding the responsibility of the manufacturer, there is a common chain value of responsibility that exists in European law which is stated as follow:

Supplier → Manufacturer → Seller → Buyer

Nevertheless, this chain-of-sales concept is not relevant in the 3D printing industry because there is a large number of suppliers that could possibly be held accountable. Here is a non-exhaustive list of potentially liable actors: - The manufacturer or the supplier of the 3D printer and/or its printing materials; - The printer’s owner; - The person who sold or designed the original object; - The person who created or shared the CAD file; - The person who created the object using the printer; - The person who sold the 3D-printed object…

To date, there is still no specific jurisprudence relating to the rules of civil liability for a product produced in 3D. It is an unknown territory for manufacturers. Indeed, as the defect can come from a lot of possible scenarios, it is almost impossible, using the traditional tort law, to sort out who is actually responsible in case of a defect. Those possible scenarios can include: - The original product design used to create the 3D printed object was defective; - The original CAD file was defective; - A defect was introduced into the CAD file as it was uploaded to a file-sharer; - The CAD file was corrupted during the process of downloading; - The defect was caused by an issue with the 3D printer; - The defect was caused by an issue in the raw material used in the 3D printer - Human error in implementing the digital design caused the defect; - Human error in using the 3D printer and/or the raw material.

However, while there is an almost infinite number of actors that could be liable, there is a way to avoid legal difficulties in this area: having a perfect process of manufacturing (Freeman, 2013). Processes allow the manufacturer and the client, here the space agencies, to be on the same page regarding the expectations and the quality of the product. With a battery of test and requirements, the responsibility of the private entity can be reduced.

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10.4.2 For the crewed mission: Health issues and Tort Law In the case of the proposed mission, the crew present will have to live in a closed environment, far from Earth which could be dangerous for the worker’s physical health.

In fact, a study conducted by researchers from the Georgia Institute of Technology and from the UL Chemical Safety in April 2018, showed that 3D printers may be dangerous to human lungs due to the presence of nanoparticles. It was concluded after two years of research that “many 3D printers emit ultrafine particles during operation”. These particles, which are measured in nanometers, are breathable and once they reach the lungs, they persist throughout life (Underwriters Laboratories, 2018). All research conducted on 3D printers thus far, appears to reach similar conclusions: 3D printers are harmful to human health regardless of the model chosen. Only one solution has been advocated thus far: staying away from the printer when it is working. This recommendation that is not an option in our case thus risk mitigation plans are required, for example options could include using the printers in an enclosed area with strong air filtering and personal protective equipment.

Thus, regarding this study it might be a challenge to have multiple printers onboard for a three years mission. This significant risk in regards to crew health would require addressing at an insurance level in tandem with any mitigation plan.

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11 Ethics

The in space manufacturing process must be risks assessed and evaluated, as with any on-Earth activity. These newly developed techniques are created by humans to impact on human lives. The welfare of said humans is paramount to mission objectives being successfully completed in any crewed mission. The following section shall attempt to highlight some of the social impacts and ramifications of the actions under discussion.

Since Antiquity, ethics has been a subject of reflection to which many philosophers and thinkers have contributed, from Aristotle and Descartes to Spinoza and Kant to name a few. Through this profusion of philosophical works and research in the human and social sciences, it appears that there is no consensus definition of ethics. The Greek etymology (ethos and ethicos) and Latin (mos and moralis) propose two meanings of the term "ethics": - A set of rules enforced and respected by the members of a society, rules given as a guide to conduct and stated in terms of good and bad - A philosophical discipline that reflects on these rules and representing their foundations and ends (Cruz, 2017)

For the majority of authors, ethics is considered at the very least as defining what is good and what is wrong. The origin of these values is very varied. The individuals draw them from religion, the belief in a superior technology, the fear of scientific progress, the rational reflection, the search for creation of economic value, social survival or even education. In addition, in a given organization, each individual has an ethic that serves as a benchmark when he/she must make a decision and act. Ethics can, therefore, be defined as a way of thinking that guides individual actions (Cruz, 2017).

11.1 Ethics and Automation Ethical considerations in regards to in space manufacturing are not limited to situations where humans are continuously present. Robotics and automation ethics is a sub area of ethics dedicated to examining the ramifications of the described scenario (Tzafestas, 2018).

There are a number of questions that any developer should be mindful of during the decision making phase of facility development. These can be most easily understood within two categories, the impact of automation on society, and the relationship between humans and artificial intelligence (AI).

The impact of automation is already visible in society, for example, the impact of self-service checkouts on job opportunities in supermarkets. A fully automated in space manufacturing facility would require high levels of sophistication in its robotics. How will on Earth manufacturing jobs be impacted? Would meeting this mission objective make humans obsolete? Ethicists have identified this as a question that will require an answer within the foreseeable future (Rotman, 2013). Further to this, AI technological advancements are beginning to lead to socially competent robots (Tzafestas, 2018). Would a socially competent robot have the same social needs as humans and if so, what supports would robots require in

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Chapter Two: Deep Space Crewed Mission regards to their well-being if placed within a fully automated facility? While there is currently no solution to these potential issues, mindfulness of their existence would be useful in development planning.

11.2 Mimicking Mother Nature The main consideration of any ethical assessment is how any new technology can be misused. Bio-printing could lead to changes in the human body that should not be possible without technical assistance. This could lead to the creation of super-humans. With bio-printing, it would appear that Medicine shall eventually be able to create organs with higher capacities and a longer life expectancy than is naturally possible (Gilbert, et al., 2017).

This would be an artificial enhancement of the human body that could possibly lead to the creation of synthetic humans. While bio-printing is a significant advancement in medicine, the limit between augmented humans and the simple cure is very thin. For this reason, bio-printing must remain regulated and must be used for the sole purpose of saving lives (Gilbert, et al., 2017).

With that in mind, the following questions arise: by creating bio-printing, are humans trying to play “God” creating the human equivalent of hybrid-creation attempts between animals? And shouldn’t Nature be left to its preset limitations?

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Added Value

ADDED VALUE

In this paper, the benefits of using in space manufacturing have been highlighted and discussed. In addition to this, here is one fundamental added value: the positive environmental impact of using this technology. This impact can be further increased by the democratization of in space manufacturing.

When launching a Soyuz rocket, the booster launchers release kerosene and liquid oxygen. Ariane 5, and Vega, to a lesser extent, both exhaust hydrochloric acid and alumina. In addition, a large amount of water is projected onto the launching table which results in the increase of the cloud of combustion, and, finally, a large part of the pollutants emitted fall close to the launch area (David, 2017).

These gases remain on the ground distributed radially approximately 1 km around the launching pad. Further information is required on the environmental impact of rocket launches and re-entering space debris on the middle and upper atmosphere. Research supports the conclusion that rocket emissions and debris are directly affecting the ozone (David, 2017).

This issue can be mitigated by in space manufacturing. Utilizing these technologies can decrease a significant percentage of the supplies required for a crewed deep-space mission via re-supply launches. Consequently, the associated greenhouse gases would be decreased (Ghidini, 2016).

In addition, the reduced requirement of re-supply missions will subsequently reduce energy consumption and the CO₂ footprint on Earth. Furthermore, as every product can be used multiple times, the recycling process is not needed and therefore energy would be saved, in particular for metal components (Ghidini, 2016).

The majority of manufacturing methods, inclusive of 3D printing, have numerous negative side effects on the environment. By utilizing in space manufacturing, these environmental impacts can be mitigated through reduced power consumption, elimination of nanoparticles, greenhouse gas exhaust, and reduction of chemical run-off. Hence, in space manufacturing can be deemed to be the lesser of two evils (Keppner, et al., 2018). Although the number of rocket launches to re-supply is not significant, the benefits of using space as a medium for creating products are not negligible. Furthermore, there will be less wastage since any product printed in space will be put to use whereas stockpiles may or may not be utilized. Therefore, despite the fact that there is currently no precise data about how much gas is released, reducing the number of rockets launched and the quantity of material needed to resupply the missing or broken ones reduces the supply chain.

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Finally, according to Ghidini (2013), 3D printing can protect the environment by guaranteeing: 1. Significant weight reductions: can go up to 95% but is usually is a bit more than 50% of the initial weight that is reduced; 2. Radical reduction of waste material compared to classical subtractive manufacturing; 3. Additive manufacturing lead time which could be shorter by months compared to traditional manufacturing; 4. Drastic reduction of manufacturing steps required; 5. Decrease in energy consumption and reduction of CO₂ footprint; 6. Process speed optimization.

In-space manufacturing is thus beneficial to the environment (David, 2017).

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Recommendations

RECOMMENDATIONS

Across this report, several manufacturing techniques have been proposed to address the constraints and requirements that emerge from sending a crew into deep space for a period of up to three years. The ISS was utilized to set a baseline to establish the essential needs of a crew and common bottlenecks associated with planning a 3-year mission. The following section aggregates the key recommendations tailored to (i) space agencies and private space players with plans to send a crewed mission on a 3-year journey as well as (ii) the space and 3D printing industries as a whole.

Food and Health Manufacturing Processes Life support and bioregenerative systems are suggested to operate in parallel to support basic life needs in an efficient manner. Algae processing, bioreactors to grow microbes, and plant generation have been identified as key developments in bioregenerative systems because of their ability to nourish crew members and produce adequate atmospheric requirements. Some experiments have been conducted on the ISS, but there is still a significant technological gap to apply these solutions to more advanced mission architectures. Section 2.1 of Chapter 2 goes into more detail on how life support, bioregeneration, and waste management can operate in parallel effectively.

Medical Supplies and Drugs Medical standardization is required in order to streamline the ISM process for medical devices and medicine. Medical devices are currently 3D printed on the ISS with FDM techniques while manufacturing medicine still remains a terrestrial challenge. To create standardization and personalization, it is recommended to create patient-specific database formats for astronauts using additive manufacturing profiles. To validate manufactured medicine in space, it is suggested to further develop the following technologies on the ISS: Inkjet 3DP, Thermal Inkjet (TIJ) Printing, and Fused Deposition Modeling (FDM) with respect to the printing of medicine in space.

The final area for improvement is shelf life of medicine. Advanced radiation shielding techniques will heavily support this process and have been detailed in Section 2.6.2 of Chapter 2. This continues to pose a risk to long duration missions.

Mental Health It is recommended that space agencies place an emphasis on crew’s hobbies and family dynamics. Specialized games and scale model figurines of family members can be 3D printed using FDM techniques to help astronauts feel more connected to home. Section 2.5 of Chapter 2 provides further detail regarding this recommendation.

Standardization and Commercialization Standardization and commercialization have been identified as key areas to further develop with respect to ISM. Since this is still a niche industry, proper standards and design guidelines such as handling,

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Recommendations operability, and reliability will need to be continuously monitored on the ISS while the ground support revises and documents and issues. Commercialization is evolving rapidly, with Made in Space and TUI leading the way, but this market would benefit from more actors. To this point, agencies and commercial companies should consider creating a standard database consisting of 3D models for parts exhibiting high failure rates. This would provide astronauts with the ability to quickly react to situations as they arise. With deep space communication latency, astronauts may not have time to wait for ground support to provide solutions.

It is also suggested for space agencies and private companies to create modular designs with as many common or identical parts as possible. This way, ISM can easily be utilized for replacement parts and assembly will be simpler.

In conjunction with additive manufacturing, robotics should be developed to remove as much human interfacing as possible for secondary processing of 3D printed parts. As there will always be some human interfacing required, astronaut training will need to be developed and tailored to specific and detailed operations. Astronauts must be able to identify the failed components within the 3D printers and repair them readily. This might require launching stock emergency spares with known high failure rates.

The final recommendation for this section is to update the Design Review Architecture for Human Landing on Mars from 5.0 to 6.0. Since a Mars mission closely follows this reports mission architecture, it may be beneficial for NASA to consider updating their design guideline to include ISM techniques with a focus on additive manufacturing; enabling cost reductions on the long term.

Electronics The industry should focus on developing space-grade recyclable electronic and electrical components that can introduce higher sustainability on deep space missions. As highlighted in Section 1.1 of Chapter 1, the most common failure today on the ISS comes from electrical components, hence a clear emphasis should be placed on the ability to mitigate these risks without the need of resupply or specialized spare parts. Validation for 3D printed electronics should occur in parallel with the creation of the FabLab ISS additive manufacturing plans. Aerosol jet printing has been the primary method identified in this report for further development with a TRL of 5.

Metal Printing The FabLab project associated with the ISS is currently planned to complete by 2024. It is recommended that this validation process continues to move forward efficiently with key actors such as Made in Space and TUI. The most interesting improvement currently being developed terrestrially is the MAMBA for its ability to integrate recycling as well as 3D printing. This integration between recycling and manufacturing will be imperative for deep space crewed missions.

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Recommendations

Assembly Assembly in space is critical in reacting to the extreme environments posed by deep space missions. It is recommended to study 3D printing of radiation protection materials such as aluminum and polyethylene and document the repair and assembly process.

In addition, it is advocated to further develop the capability to 3D print large antennas. This will be used to mitigate the effects of long distance power loss during communication. The large structure printing and assembly of antennas are not yet validated but require further study and present an interesting value add. Further information can be found in Section 3.2 of Chapter 2.

Sustainability The sustainability that ISM can generate for a spacecraft is likely its largest benefit. As such, it is suggested to develop more compact printers capable of printing multiple materials. This will help reduce the required volume capacity and overall mass for the various ISM techniques.

Further advancement of recycling techniques within the realm to ISM will greatly benefit future deep space crewed missions. This eliminates the need for resupply if performed correctly and efficiently. TUI is heavily focused in this area with their Refabricator and MAMBA products. Although they have not been tested in a space environment, successful integration will provide an enormous improvement in the way repairs and spares are approached.

Another recommendation is to increase the sustainability of the ISS itself to begin to simulate and replicate deep space mission parameters. Attempting to reduce the number of resupplies to the ISS by leveraging ISM will help define further technology gaps and areas of improvement. The recommendation is to start by reducing the resupply frequency to once per year. As the ISS operates in LEO, this will be a low risk feasibility study since the required material can be supplied in the case of emergency.

With a larger emphasis being placed on ISM, it is recommended to focus on efficiency and power consumption requirements. Having more 3D printers on board will drive higher power requirements and more complex power generation architectures. At the same time, having the capability to manufacture and assemble solar panels directly in space can enable higher power generation as mentioned in Section 3.2.2 of Chapter 2. This will need to be a central focus in planning for future deep space crewed missions.

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References

CONCLUSION

3D printing emerged late last century. It started as a design aid and prototyping tool but its potential seized the imagination and business instincts of many. The ability to rapidly produce fully customizable objects opened up a realm of possibilities. This potential was quickly transformed into applications and hardware models. While a community of “do it yourself” makers was growing, the technology started to seep into the traditional manufacturing industry, mainly in the modeling and prototyping phases. As the variety of 3D printable materials and quality evolved, manufacturers started producing end products through additive manufacturing.

Today, 3D printing technology touches upon almost every industry but only for a specific set of products. The most developed 3D printing technologies operate using plastics, but new 3D printing technologies are focusing on other materials such as metal, glass, concrete, food, and textiles to name a few. 3D printing applications in the industry will generally either be high end, benefitting from the ability to customize the products, or experimental. On the other hand, the technology is usually not used in high volume production lines and the price for a market ready product will be high.

Despite those challenges, the space industry is relatively resilient to these disadvantages. In fact, space missions usually do not require mass produced components, subsystems and systems. Additionally, NASA in collaboration with commercial partners such as Made in Space, has developed and operated ISM technologies with a price tag which is negligible compared to the mission budget and the overall return on investment in the form of cost savings in the long term.

A space mission experiences a plethora of premature failures combined with expected wear and tear. The ability to readily produce on-demand components in space can enable space stations’ personnel, with minimal expertise in manufacturing, to tend to the needs of the space stations’ systems. As such, in-space manufacturing technologies are highly compatible with a crewed mission operational environment, reducing the amount of spare storage required.

While LEO missions such as the ISS can act as experimental platforms for ISM technologies, the real challenge for these technologies will be in such missions where resupply is unavailable e.g. deep space exploration missions. As such, this report was developed around the idea of leveraging operational and in development ISM technologies that can support a 3-year deep space crewed mission of seven people.

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This report’s conclusions are laid out below: 1. Like in many space related industries, the ISM industry is still in its infancy, with governmental agencies, such as NASA, partnering with commercial entities to advance the industry and potentially enable the creation of a space economy. 2. The technologies identified from this topic are split in: a. 3D printing by crew within a space habitat. b. 3D printing of large structures and robotically assembling them out in space. c. Manufacturing technologies which are not 3D printing (e.g., recycling, assembly, biological and chemical processes). 3. Developmental and manufacturing costs of ISM technologies will be amortized over a long term, thus providing an incentive to shift the focus from an open loop resupply paradigm to a closed loop one. The ISS is expected to be used as a platform to elevate the TRL of ISM technologies in order to later on be ready for long duration deep space expeditions. 4. ISM enables products to be developed that are not easily launched into space. For example, large structures face many launch constraints and have good chances of being developed commercially through ISM. Although TRL is relatively high, operational status is not clear. 5. ISM technologies, other than 3D printing, exhibit differences in TRL, some of which are highly developed while others are still at a relatively conceptual level. 6. When the ISS experimental platform will end its operational lifetime and funds will be redirected towards long distance exploration mission; thus the TRL of 3D printing is required to be at 9 in order to accommodate the mission needs. 7. While plastics 3D printing is fairly developed, a gap exists in metal and electronic 3D printing to respond to failures similar to those encountered on the ISS today. 8. Additional crew needs in future deep exploration were identified, mainly in medicine, communication, and radiation shielding. It was also found that current 3D printing technologies have limited ability to face these challenges. 9. The recyclability was pointed out as a major contributor to long duration deep space missions sustainability, and any manufacturing attempt should address the recyclability of the final product at its end of life. 10. The modularity of components was found to be an assisting design tool to make the best use out of 3D design parts allowing to print minimal required parts to address the failure.

Having an “ideal” 3D printing manufacturing machine capable of anything from any material would obviously be an asset for space exploration, but it is also a science fiction tool. Currently, printing anything and everything is not possible. In addition, mass and power budgets are not sufficient enough to develop better printers. Still the potential of such a device is extremely attractive on Earth and in space. Advancement in 3D printing technologies in space will occur hand in hand with the launching of more crewed missions to explore our surrounding planets and moons. This technology has great prospects, in essence the further distance humankind travels, the more it will advance.

Page 102 of 118

References

REFERENCES

3D Printing industry, 2019. [online] Available at: earthquake-107240/> [Accessed 14 March 2019].

3D4MD, 2019. About us. [online] Available at: [Accessed 10 March 2019].

Activarmor, 2019. The industry leader for 3D printed casts and splints in the united states. [online] Available at: [Accessed 7 March 2019].

Akahoshia, Y., Nakamura, S., Fukushige, N. and Furusawa, N., 2008. Influence of space debris impact on solar array under power generation. International Journal of Impact Engineering, 35(12), pp.1678-1682.

AmazingAM, 2018. Additive Manufacturing Basics. [online] Available at: [Accessed 27 February 2019].

AMSC, 2018. Standardization Roadmap for Additive Manufacturing. [pdf] America Makes & ANSI Additive Manufacturing Standardization Collaborative (AMSC). Available at: [Accessed 5 March 2019].

Anderson, M., Barta, D. and Lange, K., 2015. Environmental Control and Life Support Systems for Mars Missions: Issues and Concerns for Planetary Protection. [pdf] NASA. Available at: [Accessed 28 February 2019].

Anon, 2019. Kevlar Recycling - Ballistic Recycling Intl. [online] Available at: [Accessed 12 March 2019].

Aprecia Pharmaceuticals, 2015. FDA Approves the first 3D printed drug product. [online] Available at: [Accessed 4 March 2019].

Astronautics, 2017. L0X/LH2 [online] Available at: [Accessed 14 March 2019].

Aziz, Z., 2019. Launch Of Russia’s Nauka MLM Module To ISS Postponed Until Summer 2020. UrduPoint. [online] 9 February. Available at: [Accessed 13 March 2019].

Badger, J., n.d. Robonaut. [online] Available at: [Accessed 26 February 2019].

Barry, P., 2000. Breathing Easy on the Space Station. [online] Available at: [Accessed 28 January 2019].

Barry, P., and Phillips, T., 2000. Water on the Space Station. [online] Available at: [Accessed 28 January 2019].

Barth, J., 1996. SEECA - Section 3. [online] Available at: [Accessed 7 March 2019].

BeAM Machines, 2019. Modulo 3D Printing Machine And 3D Printing Tools - Beam Machines. [online] Available at: [Accessed 14 March 2019].

Page 103 of 118

References

Bean, Q., Beshears, R., Ledbetter III, F., Ordonez, E., Prater, T., Rolin, T., Ryan, R. and Werkheiser, N., 2016. Summary Report on Phase I Results From the 3D Printing in Zero-G Technology Demonstration Mission. [pdf] NASA. Available at: [Accessed 14 March 2019].

Benoit, M.R., Li, W., Stodieck, L.S., Lam, K.S., Winther, C.L., Roane, T.M. and Klaus, D.M., 2006. Microbial antibiotic production aboard the International Space Station. Applied Microbiology and Biotechnology, 70(4), pp.402-411.

Beutel, M.E., Glaesmer, H., Wiltink, J., Marian, H. and Brahler, E., 2010. Life satisfaction, anxiety, depression and resilience across the life span of men. The aging male, 13(1), pp.32-39.

Bigelow Aerospace, 2018. Who we are. [online] Available at: [Accessed 2 December 2018].

Bishop, S.L., 2011. From Earth Analogs to Space: getting there from here. In D. A. Vakoch, ed. 2011. Psychology of Space Exploration. Washington, DC: NASA. Ch. 3.

Brinckmann, E. and Schiller P., 2002. Experiments with small animals in BIOLAB and EMCS on the international space station. Advances in Space Research, 30, pp.809-814.

Broyan, J., Chu, A. and Ewert, M., 2014. Logistics Reduction and Repurposing Technology for Long-Duration Space Missions. [pdf] NASA. Available at: [Accessed 10 March 2019].

Bubeev, Y. and Ushakov, I., 2010. Individual subconscious adaptive processes to the Martian flight simulation. In: Anon, 61st International Astronautical Congress. Prague, Czech Republic, 27 September - 1 October 2010. s.l: s.n.

Buscaroli, G., 2018. The orthopedic corset 3D printed in polypropylene. Wasp, [online] 28 September. Available at: [Accessed 7 March 2019].

Campbell, A., 2017. Optical Communications Demonstrations. [online] Available at: [Accessed 6 March 2019].

CCPA, 2016. The 13th Five Year Plan for economic and social development of the people’s republic of China. [pdf] Available at: [Accessed 26 February 2019].

Chinese Academy of Sciences, 2016. China's First Zero-Gravity 3D Printing Experiment Accomplished. [online] Available at: [Accessed 26 February 2019].

Christiansen, E., Crews, J., Williamsen, J., Robinson, J. and Nolen, A., 1995. Enhanced meteoroid and orbital debris shielding. International Journal of Impact Engineering, 17(1-3), pp.217–228.

Clark, David L. n.d. In-situ propellant production on Mars: a sabatier/electrolysis demonstration plant. [pdf] Available at: [Accessed 14 March 2019].

Clowdsley, M. and Simon, M., 2013. Habitat Design Considerations for Implementing Solar Particle Event Radiation Protection. [pdf] NASA. Available at: [Accessed 14 March 2019].

Page 104 of 118

References

CMSE, 2019. Current missions of CMSE. [online] Available at: [Accessed 26 February 2019].

Copper 3D, 2018. Antibacterial 3D Printing and Active Materials! [online] Available at: [Accessed 14 March 2019].

Crusan, J. and Gatens, R., 2017. Cislunar habitation & environmental control & life support systems. In: NASA, NASA Advisory Council, Human Exploration and Operations Committee, Meeting. Washington, 28-29 March 2017. Washington: National Aeronautics and Space Administration, [online] Available at: [Accessed 18 February 2019].

Cruijssen, H.J., Ellenbroek, M., Henderson, M., Petersen, H., Verzijden, P. and Visser, M., 2014. The European Robotic Arm: A High-Performance Mechanism Finally on its way to Space. In: Dutch Space B.V., 42nd Aerospace Mechanism Symposium. 14-16 May 2014. Washington D.C.: NASA.

Cruz, X., 2017. ‘Translation Ethics : From Invisibility to Difference’. Via Panorâmicapp, 3(6), 95–105.

CSA, 2013. The Shuttle Remote Manipulator System — The Canadarm. [online] Available at: [Accessed 26 February 2019].

Dancer, J., 2017. Microalgae ready for space. Institut fur Raumfahrtssysteme News, [online] 11 December. Available at: [Accessed 27 February 2019].

David, L., (2017) How Much Air Pollution Is Produced by Rockets? [online] Available at: [Accessed 14 March 2019].

Davies, S., 2017. 3D4MD delivers concept for 3D printing medical applications in space. The magazine for Design- To-Manufacturing Innovation, [online] 9 February. Available at: [Accessed 14 December 2018].

De la Torre, G.G., Alca, M.L., Baños, R.M., Botella, C., Mestre, J.M., Guil, R. and Ramallo, M.A., 2010. Neurocognitive effects of a 3D virtual reality mood induction system in Mars- 500 chamber. In: Universidad de Cadiz, 61st International Astronautical Congress. Prague, Czech Republic, 27 September – 1 October 2010. s.l: s.n.

De Selding, P., 2016. SpaceX’s new price chart illustrates performance cost of reusability. Space News, [online] 2 May. Available at: [Accessed 14 March 2019].

Diftler, M.A., Radford, N.A., Mehling, J.S., Abdallah, M.E., Bridgwater, L.B., Yamokoski, J.D., Permenter, F.A., Motors, G., Michigan, W., Systems, O.S. and Texas, H., 2019. Robonaut 2 – The First Humanoid Robot in Space. [pdf] Available at: [Accessed 26 February 2019].

Directive 85/374/EEC, 1985. Brussels: The Council of the European Communities.

Drake, B., 2009. Human Exploration of Mars Design Reference Architecture 5.0. [pdf] NASA. Available at: [Accessed 15 March 2019].

Du, B., Daniels, V.R., Vakmans, Z, Boyd, J.L., Crady, C. and Putcha, L., 2011. Evaluation of Physical and Chemical Changes in Pharmaceuticals Flown on Space Missions. The AAPS Journal, 13(2), pp.299-308.

Page 105 of 118

References

Dunbar, B., 2017. Updating the President's 2010 Exploration Goals. [online] Available at: [Accessed 27 February 2019].

Dunbar, B.J., 2018. NASA`s Exploration Campaign: Back to the Moon and on to Mars. NASA, [online] 16 April. Available at: [Accessed 17 December 2018].

Eckart, P., 1994. Life Support and Biospherics. Munich: Herbert Utz Publishers.

Eckart, P., 1996. Spaceflight Life Support and Biospherics. Munich: Microcosm Press, and Kluwer Academic Publishers.

Elias, A.J., Charbonneau-Laliberté, S., Côté-Bigras, R., Eychenne, E., Rosa, A.C.G. and Stanimir, G., 2014. Autonomous Mission for On-Orbit Servicing Final Report. Final Report. International Space University.

Engatech, n.d. Changing the medical industry with 3D printing. [online] Available at: [Accessed 7 March 2019].

Engstrom, N.F., 2013. 3D printing and product liability: Identifying the obstacles. University of Pennysylvania Law Review Online, [e-journal] Available at: [Accessed 14 March 2019].

ESA, 2006. Space in Images - 2006 - 03 - European Robotic Arm (ERA) during flat floor testing. [online] Available at: [Accessed 11 March 2019].

ESA, 2007. Resolution on the European Space Policy. [pdf] ESA. Available at: [Accessed 27 February 2019].

ESA, 2013. Hypervelocity Impacts and protecting spacecraft. [Online] [Accessed 13 March 2019].

ESA, 2015. European Service Module. [online] Available at: [Accessed 12 March 2019].

ESA, 2017. Status and Outlook for European Exploration Envelope Programme. [pdf] Available at: [Accessed 27 February 2019].

ESA, 2019. Funding. [online] Available at: [Accessed 26 February 2019].

ESA Fly your Thesis, 2019. Meet the Team: Grain Power 3D Printing. [online] Available at: [Accessed 26 February 2019].

FabRx, 2018. Printlets [online]. Available at: [Accessed 6 March 2019].

Fisher, J. and Lee, J., 2016. Space Mission Utility and Requirements for a Heat Melt Compactor. [pdf] NASA. Available at: [Accessed 6 March 2019].

Page 106 of 118

References

Flores-abad, A., Ma, O., Pham, K. and Ulrich, S., 2014. A review of space robotics technologies for on-orbit servicing. Progress in Aerospace Sciences, 68, pp.1–26.

Flynn, K.J., Pudlo, N., Zaman, L., Tung, E. and Neches, R.Y., 2016. On the intrinsic sterility of 3D printing. PeerJ. [e- journal] Available at: [Accessed 14 March 2019].

Foust, J., 2015. NASA Not Ready To Update Mars Mission Architecture. Space News, [online] 23 January. Available at: [Accessed 10 March 2019].

Foust, J., 2018. Musk reiterates plans for testing BFR. Space News, [online] 12 March. Available at: [Accessed 7 March 2019].

Foust, J., 2019. Startup plans “gas stations” for satellite servicing. Spacenews, [online] 28 August. [Accessed 14 March 2019].

Frost, R., 2016. When is the best time for a spacecraft to launch to Mars? Forbes, [online] 15 March. Available at: [Accessed 13 March 2019].

GE Additive, 2018a. Additive-cutting-edge-joint-replacement-surgery. [online] Available at: [Accessed 7 March 2019].

GE Additive, 2018b. Additive at the cutting edge of joint replacement surgery. [online] Available at: [Accessed 14 March 2019].

Ghidini, T., 2013. ‘An Overview of Current AM Activities at the European Space Agency ESA ’ s Locations’. [pdf] ESA. Available at: [Accessed 5 March 2019].

Ghidini, T., 2016. The Use of 3D Printing for Space Applications. ROOM, [online] n.d. Available at: [Accessed 5 March 2019].

Ghosh, A. 2015. A study and approach to use regolith for 3D printing in microgravity. Individual Project. International Space University.

Gilbert, F., O’Connell, C.D., Mladenovska, T. and Dodd, S., 2017. Print Me an Organ? Ethical and Regulatory Issues Emerging from 3D Bioprinting in Medicine. Sci Eng Ethics, 24(1), pp.73-91.

Goyanes, A., Buanz, A.B., Hatton, G.B., Gaisford, S. and Basit, A.W., 2015. 3D printing of modified-release aminosalicylate (4-ASA and 5-ASA) tablets. European Journal of Pharmaceutics and Biopharmaceutics, 89, pp.157- 162.

Grunewald, S.J., 2016. Weekly Roundup: Ten 3D Printable Things – Classic Board Games. [online] Available at: [Accessed 4 March 2019].

Gu, Y., Chen, X., Lee, J.H., Monteiro, D.A., Wang, H. and Lee W.Y., 2012. Inkjet printed antibiotic- and calcium- eluting bioresorbable nanocomposite micropatterns for orthopedic implants. Acta Biomaterialia, 8(1), pp.424-431.

Harris, 2016. Harris Revolutionizes Space Antenna Production with Emerging Technology. [online] Available at: [Accessed 6 March 2019].

Page 107 of 118

References

Harrison, A.A. and Fiedler, E.R., 2011. Behavioral Health. In: D.A. Vakoch, ed. 2011. Psychology of Space Exploration. United States: NASA. Ch. 2.

HC Printing Network, 2016. 3D printer is great, and will be launched with Tiangong2. [online] Available at: [Accessed 26 February 2019].

Ho, C., Golshan, N., Kliore, A., 2002. Radio Wave Propagation Handbook for Communication on and Around Mars. [e-handbook] NASA. Available at: [Accessed 5 March 2019].

Howell, E., 2018. International Space Station: Facts, History & Tracking. [online] Available at: [Accessed 11 March 2019].

Huang, W., Zheng, Q., Sun, W., Xu, H. and Yang, X., 2007. Levofloxacin implants with predefined microstructure fabricated by three-dimensional printing technique. International Journal of Pharmaceutics, 339(1-2), pp.33-8.

Hubscher, B. and Mohon, L., 2014. 3-D Printer Powered Up on the International Space Station. NASA, [online] 7 August. Available at: [Accessed 27 February 2019].

Hughes, M., 2017. Communicating Over Billions of Miles: Long Distance Communications in the Voyager Spacecraft. All About Circuits, [online] 2 July. Available at: [Accessed 14 March 2019].

Iftikhar, U., 2019. NASA Installs Tether Refabricator Aboard ISS for In-Space 3D Printing. 3D Printing Industry, [online] 11 February. Available at: [Accessed 14 March 2019].

Ijiri, K., 2003. Life-cycle experiments of Medaka fish abroad the International Space Station. Advances in Space Biology and Medicine, 9, pp.201-216.

Images.nasa.gov., 2000. International Space Station (ISS). [image online] Available at: [Accessed 13 March 2019].

Imhof, B., 2003. The Socio-Psychological Impact of Architectural Spaces in Long-Duration Missions, Paper No. 2003- 01-2537. In: University of Technology, 33th International Conference of Environmental Systems. Vancouver, Canada, 7-10 July, 2003. s.l: SAE Mobilus.

International Space Station, 2019. Module List. [online] Available at: [Accessed 5 March 2019].

International Space University Space Studies Program, 1998. Hazards to Spaceflight. Cleveland: International Space University.

ISRO, 2018. Successful flight testing of crew escape system - technology demonstrator. [online] Available at: [Accessed 26 February 2019].

Jassim-Jaboori, A.H. and Oyewumi, M.O., 2015. 3D Printing Technology in Pharmaceutical Drug Delivery: Prospects and Challenges. Journal of Biomolecular Research and Therapeutics, 4(4), p.4.

Page 108 of 118

References

JAXA, 2018. NASA-JAXA Joint Statement on Space Exploration. [press release] 26 January 2018. Available at: [Accessed 27 February 2019].

JAXA, 2019. Remote Manipulator System:About Kibo - International Space Station - JAXA. [online] Available at: [Accessed 26 February 2019].

Johnston M.M., Werkheiser M.J., Cooper K.G., Snyder M.P. and Edmunson J.E., 2014. 3D Printing In Zero-G ISS Technology Demonstration. [pdf] NASA. Available at: [Accessed 27 February 2019].

Jones, H., 2010. Design Rules for Space Life Support Systems. [pdf] NASA. Available at: [Accessed 13 March 2019].

Jones, J., Barratt, M., Effenhauser, R., Cockell, C. and Lee, P., 2004. Medical issues for a human mission to Mars and Martian surface expeditions. JBIS - Journal British Interplanetary Society, 57(3-4), pp.144-160.

Jordan, T., 2011. The Ode: Canadarm (1981-2011) - Canadian Business. [online] Available at: [Accessed 11 March 2019].

Joshi, S., and Sheikh, A., 2015. 3D printing in aerospace and its long-term sustainability. Virtual and Physical Prototyping. 10, pp.1-11.

Keppner, B., Kahlenborn, W., Richter, S., Jetzke, T., Lessman, A. and Bovenschulte, M., 2018. ‘3D printing: Trend report for assessing the environmental impacts’, [pdf] Dessau-Roßlau: Umwelt Bundesamt. Available at: [Accessed 14 March 2019].

King, D., 2001. Space Servicing: Past, Present and Future. In: Canadian Space Agency, 6th International Symposium on Artificial Intelligence and Robotics & Automation in Space. Quebec, Canada, 18-22 June 2001. Quebec: Canadian Space Agency.

Kleos, 2019. Kleos Space In-Space Manufacturing. [online] Available at: [Accessed 7 March 2019].

Klijn, E-H. and Teisman, G.R., 2002. Institutional and Strategic Barriers to Public-Private Partnership: An Analysis of Dutch Cases. In: Erasmus University Rotterdam, British Academy of Management Conference. London, United Kingdom, 9-11 September 2002. London: BAM.

Klotz, I., 2017. Congress Mulls Options for Space Station Beyond 2024. Space.com, [online] 22 March. Available at: [Accessed 10 March 2019].

Koba, M. and Konopa, J., 2005. Actinomycin D and its mechanisms of action. Postepy High Med Dosw, 59, pp.290- 298.

Kuliś, M., 2017. Law in the Field of 3D Printing. Zortax blog, [blog] 18 December. Available at: [Accessed 14 March 2019].

Lampropoulos, N., 2018. EU auditors: Public-private partnerships suffer from widespread shortcomings. [online] Available at: [Accessed 2 March 2019].

Page 109 of 118

References

Landon, B.L., Vessey, W.B. and Barrett, J.D., 2016. Risk of Performance and Behavioral Health Decrements Due to Inadequate Cooperation, Coordination, Communication, and Psychosocial Adaptation within a Team. Houston: NASA.

Lane, H.W. and Schoeller, D.A., 2000. Nutrition in Spaceflight and Weightlessness Models. Florida: CRC Press.

Laryssa, P., Lindsay, E., Layi, O., Marius, O., Nara, K., Aris, L. and Ed, T., 2007. International Space Station Robotics : A Comparative Study of ERA, JEMRMS and MSS. Research Gate [e-article] Available at: [Accessed 14 March 2019].

Leary, K., 2017. NASA May Shift Its Focus From Mars to the Moon. Futurism. [online] 24 September. Available at: [Accessed 13 March 2019].

Lobascio, C., Lamantea, M., Cotronei, V., Negri, B., De Pascale, S., Maggio, A., Maffei, M., Foti, M. and Palumberi, S., 2008. CAB: The bioregenerative life support system. A feasibility study on the survivability of humans in a long- duration space missions. Acta horticulturae, 801, pp.465-472.

Made in space, 2014. 3D Printing in Zero Gravity Experiment. [online] Available at: [Accessed 13 March 2019].

Made in space, 2016a. Additive Manufacturing Facility. [online] Available at: [Accessed 26 February 2019].

Made In Space, 2016b. Additive Manufacturing Facility (AMF) User Manual. [pdf] Available at: [Accessed 27 February 2019].

Made In Space, 2017. New Space-Based Manufacturing Technologies Demonstrated by Made In Space. [online] Available at: [Accessed 27 February 2019].

Made in Space, 2018. Archinaut. [online] Available at: [Accessed 6 December 2018].

Manzey, D., Schiewe, A. and Fassbender, C., 1995. Psychological countermeasures for extended manned space flights. Acta Astronautica, 35(4-5), pp.339-361.

Materialise, 2019. Uncover deeper insight with 3D anatomical models. [online] Available at: [Accessed 7 March 2019].

McAlister, C. and Wood, J., 2014. The potential of 3D printing to reduce the environmental impacts of production. In: Sea Green Trees S.L, ECEEE Industrial Summer Study Proceedings: Rettool for a competitive and sustainable industry. Arnhem, The Netherlands, 2-5 June 2014. Arnhem: ECEEE.

Meléndez, P.A., Kane, K.M., Ashvar, C.S., Albrecht, M. and Smith, P.A., 2008. Thermal inkjet application in the preparation of oral dosage forms: dispensing of prednisolone solutions and polymorphic characterization by solid- state spectroscopic techniques. Journal of Pharmaceutical Sciences, 97(7), pp.2619-2636.

Murata, Y., Yasuda, T., Watanabe-Asaka, T., Oda, S., Mantoku, A., Takeyama, K., Chatani, M., Kudo, A., Uchida, S., Suzuki, H., Tanigaki, F., Shirakawa, M., Fujisawa, K., Hamamoto, Y., Terai, S. and Mitani, H., 2015. Histological and Transcriptomic Analysis of Adult Japanese Medaka Sampled Onboard the International Space Station. PLOS One [e-

Page 110 of 118

References article] Available at: [Accessed 6 March 2019].

Naef, S., 2018. The radiation mitigation handbook : technologies, drugs and operational approaches to limit radiation for long duration human spaceflight. Individual Project. International Space University.

NASA, 2007. Human Needs: Sustaining Life During Exploration. [online] Available at: [Accessed 12 March 2019].

NASA, 2011. The Sabatier System: Producing Water on the Space Station. [online] Available at: [Accessed 12 March 2019].

NASA, 2013. Orbital Debris Management & Risk Mitigation. [pdf] Available at: [Accessed 12 March 2019].

NASA, 2015a. Reference Guide to the International Space Station. [e-book] Houston: Johnson Space Center. Available at: [Accessed 11 December 2018].

NASA, 2015b. Meals Ready to Eat: Expedition 44 Crew Members Sample Leafy Greens Grown on Space Station. [online] Available at: [Accessed 7 December 2018].

NASA, 2015c. Life Support Baseline Values and Assumptions Document. [pdf] Available at: [Accessed 12 March 2019].

NASA, 2016a. Risk of Adverse Cognitive or Behavioral Conditions and Psychiatric Disorders. [pdf] Accessed from [Accessed 10 February 2019].

NASA, 2016b. National Aeronautics and Space Administration ( NASA ) Emergency Medical Procedures Manual for the International Space Station ( ISS ) [partial] [pdf] Available at: [Accessed 14 March 2019].

NASA, 2017a. Full Circle: NASA to Demonstrate Refabricator to Recycle, Reuse, Repeat. [online] Available at: [Accessed 27 February 2019].

NASA, 2017b. About the Kibo Laboratory. [online] Available at: [Accessed 6 March 2019].

NASA, 2017c. Soyuz Landing [online] Available at: [Accessed 4 March 2019].

NASA, 2017d. Risk of Adverse Health Outcomes and Decrements in Performance due to In-Flight Medical Conditions. [pdf] NASA. Available at: [Accessed 14 March 2019].

NASA, 2018a. Commercial Space Transportation. [online] Available at: [Accessed 27 February 2019].

Page 111 of 118

References

NASA, 2018b. National Space Exploration Campaign Report. [pdf] NASA. Available at: [Accessed 2 February 2019].

NASA, 2018c. Power And Propulsion Element (PPE) NASA Unique Requirements. [pdf] NASA. Available at: [Accessed 14 March 2019].

NASA, 2018d. Risk of Adverse Health Outcomes & Decrements in Performance due to Inflight Medical Conditions. [online] Available at: [Accessed 15 March 2019].

NASA, 2019a. Vegetable production systems (VEGGIE). [online] Available at: [Accessed 11 March 2019].

NASA, 2019b. NASA - Refabricator. [online] Available at: [Accessed 26 February 2019].

NASA, 2019d. FY 2019 Budget Estimates. [pdf] NASA. Available at: [Accessed 28 February 2019].

NASA, 2019e. Orion Quick Facts. [pdf] Available at: [Accessed 27 February 2019].

NASA, 2019f. Intravehicular Activity Clothing Study. [online] Available at: [Accessed 13 March 2019].

NASA Advisory Council, 2018. Gateway Update. [pdf] Available at: [Accessed 27 February 2019].

NASA Inspector General, 2018. NASA’S management and utilization of the international space station. [pdf] NASA. Available at: [Accessed 14 March 2019].

NASA SBIR/STTR, 2019. SBIR/STTR Firm Details - Made in Space, Inc. [online] Available at: [Accessed 8 March 2019].

National Research Council, 1997. Protecting the space station from meteoroids and orbital debris. Washington, DC: Advances in the Astronautical Sciences.

National Research Council, 2014a. 3D printing in space. Washington, DC: The National Academies.

National Research Council, 2014b. Pathways to Exploration: Rationales and Approaches for a U.S. Program of Human Space Exploration. Washington, DC: The National Academies Press.

National Space Policy Secretariat, 2017. Implementation Plan of the Basic Plan on Space Policy (revised FY2017) (Overview). [pdf] Available at: [Accessed 25 February 2019]. O’Neal, B., 2016. 3dprint.com. [online] Available at: [Accessed 7 March 2019].

O'Neil, B., 2014. 3DPrint.com. [online] Available at: [Accessed 9 March 2019].

Page 112 of 118

References

Optomec, 2018a. 3D Printed Electronics - Aerosol Jet Technology - Optomec. [online] Available at: [Accessed 9 March 2019].

Optomec, 2018b. 3D Printing For Solar Cells For Alternative Energy. [online] Available at: [Accessed 9 March 2019].

Owens, A.C. and de Weck, O.L., 2016. Systems Analysis of In-Space Manufacturing Applications for the International Space Station and the Evolvable Mars Campaign. In: Massachusetts Institution of Technology, AIAA Space Conference. California, United States, 13-16 September 2016. California: AIAA.

Owens, A.C., Do, S., Kurtz, A. and de Weck, O., 2015. Benefits of Additive Manufacturing for Human Exploration of Mars. In: Massachusetts Institute of Technology, 45th International Conference on Environmental Systems. Washington: United States, 12-16 July 2015. s.l: s.n.

Pardeike, J., Strohmeier, D.M., Schrödl, N., Voura, C., Gruber, M., Khinast, J.G. and Zimmer, A., 2011. Nanosuspensions as advanced printing ink for accurate dosing of poorly soluble drugs in personalized medicines. International Journal of Pharmaceutics, 420(1), pp.93-100.

Parry, W., 2007. The future of space foods: bugs. Discover, [online] 24 October. Available at: [Accessed 10 March 2019].

Patel, N., 2017. NASA Officially Cancels the Asteroid Redirect Mission. Inverse, [online] 14 June. Available at: [Accessed 13 March 2019].

Patterson, M.J., Hamley, J.A., Sarmiento, C., Manzella, D.H., Sarver-Verhey, T., Soulas, G.C. and Nelson, A., 1994. Plasma contactor development for Space Station. ResearchGate. [e-article] Available at: [Accessed 14 March 2019].

Perez, E., Block, M., Espalin, D., Winker, R., Hoppe, T., Medina, F. and Wicker, R., 2012. Sterilization of FDM- Manufactured parts. ResearchGate. [e-journal] Available at: [Accessed 14 March 2019].

Phys.org, 2019. India plans manned space mission by December 2021. [online] 11 January. Available at: [Accessed 10 March 2019].

Prater, T., Werkheiser, N., Ledbetter, F. and Morgan, K., 2018. In-Space Manufacturing at NASA Marshall Space Flight Center: A Portfolio of Fabrication and Recycling Technology Development for the International Space Station. [online] Available at: [Accessed 27 February 2019].

Prater, T.J., Bean, Q.A., Beshears, R.D., Rolin, T.D., Werkheiser, N., Ordonez, E.A., Ryan, R.M. and Ledbetter III, F.E., 2016. Summary report on phase I results from the 3D Printing in Zero G technology demonstration mission, volume I. [pdf] NASA. Available at: [Accessed 14 March 2019].

Rask, J., Vercoutere, W., Navarro, B. and Krause, A., 2008. Space Faring The Radiation Challenge. [pdf] NASA. Available at: [Accessed 9 March 2019].

Revival Observation, 2018. Can the project "Eye of the Sky" be constructed in Space? the 3D printer, which can manufacture products as big as the 2 times of the ones produced by NASA 3D printer, will be installed in Chinese

Page 113 of 118

References

Space Station. [online] Available at: [Accessed 26 February 2019].

Robinson, J.A.R., Evans, C.A., Tate, J. and Uri, J., 2008. International Space Station Research-Accomplishments and Pathways for Exploration and Fundamental Research. In: NASA, 46th AIAA Aerospace Sciences Meeting and Exhibit. 7-10 January 2008. Nevada: AIAA.

Rotman, D., 2013. Automation is reducing the need for people in many jobs. Are we facing a future of stagnant income and worsening inequality? MIT Technology Review, [online] 12 June. Available at: [Accessed 15 December 2018].

Rovera, A., 2014. The astronaut daily schedule. [online] Available at: [Accessed 14 March 2019].

Saunders, S., 2017. The Refabricator Will Be Recycling Plastic and 3D Printing Onboard the ISS Next Year. 3DPrint.com, [online] 5 September. Available at: [Accessed 11 December 2018].

Saunders, S., 2018. HiETA Uses Renishaw Metal 3D Printer to Take Heat Exchangers From Prototyping to Commercial Production. 3DPrint.com, [online] 2 January. Available at: [Accessed 12 March 2019].

Satmarin, 2019. Breaking the Maritime Satellite Barrier. [online] Available at: https://www.satmarin.com/2018/05/31/size-matters/> [Accessed 4 March 2019].

Schwartz, A., 2016. Here’s how humans could colonize Mars without giving up meat. Business Insider, [online] 14 July. Available at: [Accessed 7 March 2019].

Schrijver, C. and Siscoe, G., 2012. Heliophysics. Cambridge: Cambridge University Press.

Scott, C., 2016. What’s next for China’s Zero-Gravity 3D Printer? Slowly, More Details Emerge. [online] Available at: [Accessed 26 February 2019].

Shaw, J.A., 2013. Radiometry and the Friis transmission equation. American Journal of Physics, 81, p.33.

Singleterry, R., 2013. Radiation engineering analysis of shielding materials to assess their ability to protect astronauts in deep space from energetic particle radiation. Acta Astronautica, 91, pp.49-54.

Skomorohov, R., Hein, A.M. and Welch, C., 2016. In-orbit Spacecraft Manufacturing: Near-Term Business Cases. Individual Project. International Space University.

Stine, G.H., 1997. Living In Space., New York: M. Evans and Company, Inc.

Stratasys, 2019 Introducing stronger more flexible PolyJet parts. [online] Available at: [Accessed 7 March 2019].

Stutte, G.W., Newsham, G., Morrow, R.M., Wheeler, R.M. 2011. Concept for Sustained Plant Production on ISS using VEGGIE Capillary Mat Rooting System. [pdf] NASA. Accessed from: [Accessed 6 December 2018].

Page 114 of 118

References

Swack, M., 2016. New York Fashion Week: New Movement in 3D Printed Fashion By ThreeASFOUR, Travis Fitch and Stratasys. Stratasys Blog, [online] 16 February. Available at: [Accessed 14 March 2019].

Swissto12, 2019. Swissto12 Products. [online] Available at: [Accessed 7 March 2019].

Terfansky, M., Thangavelu, M., Fritz, B. and Khoshnevis, B., 2013. 3D Printing of food for space missions. In: AIAA Space Forum, AIAA SPACE 2013 Conference and Exposition. San Diego, United States, 10-12 September 2013. San Diego: AIAA.

Tethers Unlimited Inc., 2018. Tethers Unlimited Capabilities. [online] Available at: [Accessed 3 December 2018].

The Straits Times, 2017. ‘Iran plans manned space mission’. [online] 16 September. Available at: [Accessed 14 March 2019].

The Washington Times, 2019. Iranian instability grows. [online] 24 February. Available at: [Accessed 28 February 2019].

The White House, 2017. Presidential Memorandum on Reinvigorating America's Human Space Exploration Program. [pdf] Available at: [Accessed 27 February 2019].

Thirsk, R., Kuipers, A., Mukai, C. and Williams, D., 2009. The space-flight environment: the International Space station and beyond. Canadian Medical Association journal = journal de l'Association medicale canadienne, 180(12), pp.1216–1220.

Torossian, R., 2018. Russia to Send Ship to Mars by 2019. Medium. [online] 21 March. Available at: [Accessed 7 March 2019].

Trujillo, A.E., Moraguez, M.T., Owens, A., Wald, S.I. and De Weck, O., 2017. Feasibility Analysis of Commercial In-Space Manufacturing Applications. In: Massachusetts Institute of Technology, AIAA SPACE and Astronautics Forum and Exposition. Orlando, USA, 12-14 September 2017. Orlando: ARC.

Tzafestas, S.G., 2018. Ethics in robotics and automation: a general view. International Robotics & Automation Journal, 4(3), pp.229-234.

Underwriters Laboratories, 2018. UL Chemical Safety and Georgia Institute of Technology release pioneering 3D printing research. PR Newswire, [online] 12 November. Available at: [Accessed 14 March 2019].

Upson, S., 2019. Watch blue origin launch a rocket stuffed with NASA gear. Wired. [online] 23 January. Available at: [Accessed 7 March 2019].

Vialva, T., 2018a. Chinese scientists conduct ceramic 3D printing tests off-world construction. 2018 [online] Available at: [Accessed 26 February 2019].

Page 115 of 118

References

Vialva, T., 2018b. Nscrypt Enhances U.S Army’s Additive Manufacturing Capabilities With Factory In A Tool Platform - 3D Printing Industry. [online] Available at: [Accessed 9 March 2019].

Ventola, L., 2014. Medical Applications for 3D Printing: Current and Projected Uses. Pharmacy and Therapeutics, 39(10), pp.704-711.

Wall, M., 2017. Building Huge Structures in Space: ‘Archinaut’ Takes Another Step. [online] Available at: [Accessed 6 March 2019].

WaybackMachine, 2004. ASP: About Us: TRL Intro. [online] Available at: [Accessed 14 March 2019].

Werkheiser, N., 2018. In-Space Manufacturing (ISM): Make it, Don’t Take It!!. [pdf] NASA. Available at: [Accessed 27 February 2019].

Watkin, H., 2017. Reflection 3D Technology is Upgrading the Family Photo with Personal 3D Printed Models. [online] Available at: [Accessed 6 March 2019].

Yamashita, M. and Wheeler, R.M., 2014. Habitation in space. In: M. Macdonald and V. Badescu, ed. 2014. The international handbook of space technology. Springer-Verlag Berlin Heidelberg. Ch.4.

Yang, Y., Tang, L., Tong, L. and Liu, H., 2009. Silkworms culture as a source of protein for humans in space. Advances in Space Research, 43, pp.1236–1242.

Yeggi, 2019. Room Divider design database. [online] Available at: [Accessed 4 March 2019].

Zabel, P., Bamsey, M., Schubert, D. and Tajmar, M., 2016. Review and analysis of over 40 years of space plant growth systems. Life Sciences in Space Research, 10, pp.1-16.

Zak, A., 2016. Russia approves its 10-year space strategy. The Planetary Society [online] 23 March. Available at: [Accessed 26 February 2019].

Page 116 of 118