National Aeronautics and Space Administration

DRAFT Launch Propulsion Systems Roadmap Technology Area 01

Paul K. McConnaughey, Chair Mark G. Femminineo Syri J. Koelfgen Roger A. Lepsch Richard M. Ryan Steven A. Taylor

November • 2010 DRAFT This page is intentionally left blank

DRAFT Table of Contents Foreword Executive Summary TA01-1 1. Introduction TA01-2 1.1. Technical Approach TA01-2 1.2. Benefits TA01-5 1.3. Applicability/Traceability to NASA Strategic Goals, AMPM, DRMs, DRAs TA01-6 1.4. Top Technical Challenges TA01-7 2. Detailed Portfolio Discussion TA01-7 2.1. Portfolio Summary and Work Breakdown Structure TA01-7 2.2. Technology Description and Development Details TA01-8 2.2.1. Solid Rocket Propulsion Systems (TABS 1.1) TA01-8 2.2.2. Liquid Rocket Propulsion Systems (TABS 1.2) TA01-8 2.2.3. Air-Breathing Propulsion Systems (TABS 1.3) TA01-9 2.2.4. Ancillary Propulsion Systems (TABS 1.4) TA01-9 2.2.5. Unconventional/Other Propulsion Systems (TABS 1.5) TA01-9 2.2.6. Technology Area Roadmaps and Table Descriptions TA01-9 2.2.6.1. Solid Rocket Propulsion Systems TA01-10 2.2.6.2. Liquid Rocket Propulsion Systems TA01-11 2.2.6.3. Air-Breathing Launch Propulsion Systems TA01-12 2.2.6.4. Ancillary Propulsion Systems TA01-13 2.2.6.5. Unconventional/Other Propulsion Systems TA01-14 2.2.7. Technology Area Tables TA01-15 2.2.7.1. Solid Rocket Propulsion Systems TA01-15 2.2.7.2. Liquid Rocket Propulsion Systems TA01-16 2.2.7.3. Air-Breathing Launch Propulsion Systems TA01-17 2.2.7.4. Ancillary Propulsion Systems TA01-19 2.2.7.5. Unconventional/Other Propulsion Systems TA01-21 3. Interdependency With Other Technology Areas TA01-23 4. Possible Benefits to Other National Needs TA01-24 Acronyms TA01-25 Acknowledgements TA01-26

DRAFT Foreword NASA’s integrated technology roadmap, including both technology pull and technology push strategies, considers a wide range of pathways to advance the nation’s current capabilities. The present state of this effort is documented in NASA’s DRAFT Space Technology Roadmap, an integrated set of fourteen technology area roadmaps, recommending the overall technology investment strategy and prioritization of NASA’s space technology activities. This document presents the DRAFT Technology Area 01 input: Launch Propulsion Systems. NASA developed this DRAFT Space Technology Roadmap for use by the National Research Council (NRC) as an initial point of departure. Through an open process of community engagement, the NRC will gather input, integrate it within the Space Technology Roadmap and provide NASA with recommendations on potential future technology investments. Because it is difficult to predict the wide range of future advances possible in these areas, NASA plans updates to its integrated technology roadmap on a regular basis.

DRAFT Executive Summary oxidizer from the atmosphere and could be part Safe, reliable, and affordable access to low-Earth of an integrated system that includes more con- (LEO) orbit is necessary for all of the nation’s ventional rockets to reach the vacuum of space. space endeavors. The Launch Propulsion Systems Hypersonic air-breathing systems, as demonstrat- Technology Area (LPSTA) addresses technologies ed by X-43 and X-51, are still in the experimental that enhance existing solid or liquid propulsion stage. Improvements in ancillary propulsion sys- technologies or their related ancillary systems or tems would include the supporting subsystems for significantly advance the technology readiness lev- conventional propulsion systems, including con- el (TRL) of newer systems like air-breathing, un- trols and smaller rockets not directly responsible conventional, and other launch technologies. The for lift to orbit. Unconventional launch technolo- LPSTA consulted previous NASA, other govern- gies include systems that do not rely solely on on- ment agencies, and industry studies and plans for board energy for launch or that use unique tech- necessary technology developments, as well as nologies or propellants to create rocket thrust. subject matter experts to validate our assessment Included in this area are technologies that are at of this field, which has fundamental technologi- a very low TRL or that do not map into the other cal and strategic impacts on the nation’s space ca- propulsion taxonomies. pabilities. Solid rocket motors (SRMs) have many advan- The LPSTA selected its most promising tech- tages over liquid systems such as high-energy den- nologies based on critical figures of merit, in- sity and long-term stability and storability. How- cluding propulsion system production and op- ever several disadvantages limit their applicability, erational costs, game-changing operational and which can be reduced or eliminated by advanc- performance capabilities, and national needs also ing the technology base of SRMs to make them identified by other government agencies and in- more attractive alternatives to liquid systems. Key dustry. The technologies reflect the future launch disadvantages for SRMs today are lower perfor- needs of the NASA mission directorates, oth- mance (Isp), lack of throttling on demand or abil- er government agencies, and commercial indus- ity to shut down on command, environmental try, which include a wide range of payload classes, concerns, and ground operations costs associat- from small (<2 metric tons (t)) to >50 t. ed with safety issues in handling large solid seg- The LPSTA identified a number of challeng- ments. This roadmap proposes technology invest- es across the range of possible launch propulsion ments that address some of these disadvantages, as technologies to be developed over the next 20 well as enhance the advantages mentioned above. years. These technologies were prioritized based Key areas for improvement include a green pro- on an LPSTA team consensus for the identified pellant alternative to current oxidizers, advancing needs and the expected return on investment for the ability to assess damage tolerance limits and each technology area. In the near term, this in- detect damage on composite cases, developing do- cludes tactical needs like high-strength oxygen- mestic sources for critical materials used in manu- compatible materials for new hydrocarbon-based facturing of SRMs, formulating advanced hybrid engines as well as more exotic technologies like fuels to get energy density equal to SRMs, and in- launch assist approaches and fusion-powered nu- vesting in the fundamental physics of SRM design clear thermal rockets (NTRs). including analysis and design tools. The LPSTA was organized around five primary Liquid rocket propulsion systems use propel- technology areas: solid rocket propulsion systems; lants (fuels and oxidizers) that are kept in a liquid liquid rocket propulsion systems; air-breathing state prior to and during flight. The advantages of launch propulsion systems; ancillary propulsion liquid rocket engines include generally higher Isp systems, which include subsystems for existing and better thrust control (including throttling and systems, as well as smaller rocket systems like RCS restart capability) than solids. Liquid rocket pro- and abort systems; and unconventional and other pulsion systems are more operationally complex propulsion systems. Solid and liquid rocket pro- than solids and require some form of active flow pulsion systems have been used since the dawn of control that introduces additional possibilities for space flight, and naturally comprise fuel and oxi- failures. The liquid propulsion roadmap addresses dizers in solid or liquid form. These technologies the critical figures of merit by proposing technolo- are reaching the limits of theoretical efficiency and gy investments in new liquid engine systems, pro- performance using conventional propellants. Air- pulsion materials research, high-density impulse breathing launch propulsion systems extract their and green propellants, and new subsystem mod- DRAFT TA01-1 eling and design tools. with robust operating margins at current technol- Air-breathing launch propulsion systems obtain ogy levels, are a promising technology of interest the oxidizer for combustion from the Earth’s at- in the mid term. Mid- to far-term technologies mosphere, which is combined with fuel brought that can provide breakthrough improvements in on board. Air-breathing engines change modes as propulsion efficiency through the application of speed and altitude increases, and transition to pure energy generated by means other than chemical rocket mode at high altitudes for the final ascent combustion, such as power beaming, nuclear fu- to space. This roadmap focuses on key technolo- sion, and high-energy density materials, are prime gies that would advance air-breathing launch pro- candidates for future investment. pulsion systems during validation flight tests and The LPSTA roadmap (Fig. 1) reflects a staged would lead to the design of a staged air-breathing development of critical technologies that include launch vehicle. These technology investments in- both “pull” technologies that are driven by known clude the development of Mach 4+ turbines for short- or long-term agency mission milestones, turbine-based combined cycles, long-duration as well as “push” technologies that generate new Mach 7+ scramjet operation, stable mode transi- performance or mission capabilities over the next tions of rocket-based and turbine-based combined 20 to 25 years. While solid and liquid propulsion cycle vehicles, an integrated air collection and en- systems are reaching the theoretical limits of ef- richment system, and detonation wave engine op- ficiency, they have known operational and cost eration. challenges while continuing to meet critical na- Ancillary propulsion systems that support the tional needs. Improvements in these launch pro- main vehicle propulsion system or provide oth- pulsion systems and their ancillary systems will er key launch vehicle functions during ascent, are help maintain the nation’s historic leadership role significant drivers in vehicle cost, complexity, and in space launch capability. Newer technologies reliability. Development of new low-cost cryo- like air-breathing launch propulsion, unconven- genic and rocket propellant (RP) valves, lines and tional, and other propulsion technologies and sys- support components is essential to support less ex- tems, while low in TRL, can radically transform pensive new vehicle development and reinvigorate the nation’s space operations and mission capabil- our nation’s technology base in this area. Some ca- ities and can keep the nation’s aerospace industri- pabilities that are within reach with up-front tech- al base on the leading edge of launch technologies. nology development include nontoxic reaction control systems, advanced sensors coupled with 1. Introduction smart control systems providing robust integrat- ed vehicle health management (IVHM), high- 1.1. Technical Approach powered electromechanical actuators (EMAs) and Reliable and cost-effective access to space is a their supporting power supply and distribution fundamental capability required for all of NASA’s systems, large robust mechanical separation sys- in-space missions. In light of this, NASA’s Of- tems, and launch abort systems with high-thrust fice of the Chief Technologist (OCT) has identi- steerable motors tied to an adaptive flight control fied the Launch Propulsion Systems Technology system. Once developed, these capabilities would Area (LPSTA) to highlight current and poten- have immediate positive impact on vehicle pro- tial technology investments by the Agency. In this duction and operational costs, overall vehicle reli- planning, Earth-to-orbit (ETO) transportation ability, and ground and flight safety. was considered, as other OCT technology areas Unconventional and other propulsion systems (TAs) addressed beyond-low-Earth orbit (LEO) include near-, mid-, and far-term technology ap- transportation. Also, the domain of this plan- proaches primarily focused on reducing the cost of ning activity was limited to ETO propulsion sys- access to space. Ground-based, hypervelocity ac- tems; other technologies, which could apply to celerators for low-cost delivery of large numbers a launch vehicle, e.g., materials, structures, ther- of small, high-g tolerant payloads to LEO are a mal, and ground systems, were addressed by other near-term technology that can provide significant TA teams. This LPSTA was then subdivided into payoff for a relatively small technology invest- five areas of emphasis, which included (1) solid ment. Orbiting space tethers that can act as the rocket propulsion systems, (2) liquid rocket pro- final stage of a launch system and relieve the per- pulsion systems, (3) air-breathing launch propul- formance requirements for vehicle ascent, poten- sion systems, (4) ancillary propulsion systems, and tially enabling fully-reusable, suborbital vehicles (5) unconventional or other propulsion systems.

TA01-2 DRAFT Figure 1: Launch Propulsion Systems Technology Area Strategic Roadmap (TASR).

DRAFT TA01–3/4 This page is intentionally left blank These five areas of emphasis highlight both the NASA in launch propulsion technologies over the current and future challenges for launch propul- last 7 years, the LPSTA roadmap presents signifi- sion technology. Much of the work performed in cant updates to planning launch propulsion tech- the last 50 years has been through solid and liquid nologies over a wide range of TRLs and approach- rocket propulsion technologies, which although es. nearing the theoretical limits of chemical com- 1.2. Benefits bustion performance and efficiency, are still not as cost effective as desired. Technology develop- The overall goals of LPSTA investments within ments in these areas tend toward enhancing exist- NASA are to make access to space (LEO) more re- ing capabilities. Other methods of reaching LEO liable, routine, and cost effective. The most com- are still at a low technology readiness level (TRL), mon metric used to assess the latter is dollars per with some being to the point of being quite theo- kilogram ($/kg) to LEO; other metrics consid- retical in nature and concept. Therefore, the tech- ered in many of the joint NASA planning activ- nologies needed to enable these new approaches ities with other governmental agencies addressed are more diverse and fundamental. Targeted areas short call-up time, launch vehicle turn-around for improvement (lowering costs of current sys- time, sortie rate, and reduced weather constraints. tems and maturing low TRL approaches) could Due to NASA’s need for lower costs as opposed benefit significantly from a prudent and balanced to the operationally responsive requirements, the technology investment strategy. LPSTA identified technologies with the following To adequately survey the landscape of neces- characteristics that could significantly lower dol- sary technologies, the LPSTA team reviewed tech- lars per kilogram to LEO based on the following nology assessments and roadmaps developed by Propulsion system production costs NASA, and other organizations over the past 15 years (a total of 16 major technology databases Propulsion system operational costs as seen in Table 1); consulted with experts in the fields of solid, liquid, air-breathing, ancillary, and Game-changing system & operational unconventional launch propulsion technologies; concepts and conducted fact-finding discussions with eight Game-changing propulsion system / aerospace companies to get their inputs on indus- subsystem efficiency and capability try needs and plans. Because there has been no National needs supported by input from significant investment or broad-based planning by other government agencies and industry Table 1. Databases Consulted by LPSTA. • Space Launch Initiative (SLI) Technology • “USA Fundamental Hypersonics” Data presentation to 16th AIAA/DLR/DGLR • National Aerospace Initiative (NAI) International Space Planes and Hypersonic Roadmaps Systems and Technologies Conference • Next-Generation Launch Technology • National Aeronautics Research and (NGLT) Plan Development Plan • Advanced Planning and Integration Office • Report to Congress: Roadmap for the (APIO) In-Space Transportation Roadmap High-Speed and Hypersonic Programs • Integrated High-Payoff Rocket Propulsion • National Hypersonics Plan: Access to Space Technology (IHPRPT) Plan Team Roadmap • Capability, Requirements, Analysis, and • Gryphon Integrated Product Team (IPT) Integration (CRAI) Database Kickoff Meeting and Roadmap • Alternate Horizontal Launch Space Access • NASA Hypersonics Project Planning Meeting Technology Roadmap • National Research Council (NRC) Decadal • Boeing National Institute of Aerospace (NIA) Survey of Civil Aeronautics Hypersonics Report • NASA Fundamental Aeronautics Program Hypersonics Project 6-Month and 12-Month Reviews (with roadmaps)

DRAFT TA01-5 figures of merit: need to improve the United States’ leadership in The overall goal of these technologies would be aerospace technology, independence from foreign to reduce launch costs by 25–50 percent over the sources of technology or materials, and the need next 20 years, with a higher reduction (>50%) ex- to maintain a basic and consistent investment in pected for non-conventional and innovative con- launch propulsion system technologies and capa- cepts. It is expected that the most feasible path to bilities. achieve this goal is to develop launch systems with 1.3. Applicability/Traceability to NASA reusable elements that reduce operational and re- Strategic Goals, AMPM, DRMs, DRAs curring hardware costs. This reduction could be To develop a responsive set of technology goals achieved with significant incremental improve- and applicable mission manifest, as well as identi- ments in current systems or approaches, e.g., a re- fy both “push” and “pull” technologies, the LPS- usable booster system. Similar benefits could result TA team reviewed the National Space Policy, the from launch assist or air-drop systems. Addition- NASA Draft Strategic Goals, and the draft Agen- al cost reductions and performance gains should cy Mission Planning Manifest for 2011. The team come from either air-breathing or non-conven- also assessed the technology and implementation tional approaches that would carry fuel on board plans of NASA’s mission directorates, including and use ambient air as the oxidizer. These sys- the Science Mission Directorate (SMD), Space tems, using existing aviation infrastructure such Operations Mission Directorate (SOMD), the Ex- as airports, runways, and jet engines, could pro- ploration Systems Mission Directorate (ESMD, duce much higher flight rates over a broader azi- and the Aeronautics Research Mission Directorate muth capability than rocket-based systems. High- (ARMD). In addition to these plans and goals, the er flight rates measured in hours instead of days, team utilized the findings of the Human Explora- weeks, or months make missions requiring mul- tion Framework Team (HEFT), which generated tiple launches or payloads much more feasible. design reference missions (DRMs) in response to To achieve these “airline like” operations, design the proposed 2011 President’s budget for NASA, teams have typically looked at applications of ad- and the results of the Agency Study Teams, which vanced air-breathing systems, with a focus on the formulated initial responses to the Office of Man- hypersonic flight regime. agement and Budget (OMB) budget guidance for The challenge for all launch propulsion systems 2011. The latter includes the Heavy-Lift Propul- is that the performance requirements dictated by sion Technology (HLPT) plan and the Commer- the physics of escaping Earth’s gravity leave very cial Crew Development (CCDev) plan. little margin in the systems to find existing tech- Results of this assessment are seen in the mis- nology solutions that reduce cost, enhance reli- sion manifest depicted in the integrated LPSTA ability, or improve operability. Whether based roadmap in Figure 1 of the Executive Summary. on conventional liquid or solid based designs, or For the SMD missions, launch vehicle require- on a hypersonic boost approach, systems to date ments result in a steady tempo of launches, com- have not exhibited the performance, design, and prising 5–8 payload launch requirements per year. life margins that lead to operational robustness. A The payload class ranges of these requirements in- true breakthrough in space access will require con- clude 3 to 4 small (<2 t) payloads per year, 2 to 3 cepts that produce significant increases in system medium (2–20 t) payloads per year, and a heavy margins while still providing a high level of per- (20–50 t) payload requirement every few years. As formance. a customer of launch services, SMD depends on However, at present solid and liquid rocket-based national capabilities and does not invest in launch propulsion systems remain the primary means for propulsion system technologies; it is primarily in- the U.S. to launch payloads to LEO. Given the terested in low-cost and reliable launch services. nation’s near-term dependence on space-based as- ESMD has a significant proposed investment in sets in LEO and other orbits, it is vital that the na- LPSTA; this can be seen in the HLPT plan and tion maintains its industrial capability to design, its emphasis on selected engine technologies, e.g., build, test, and fly updated and new solid and liq- RP and methane (CH ) prototype engines. It is uid rockets. National-level investments in tech- 4 nologies to support these systems will remain wise also reflected in the HEFT planning to support investments for the foreseeable future. This is con- a near-Earth object (NEO) mission (the require- sistent with a major finding from the LPSTA in- ment for a crewed super-heavy (>50 t) launch ve- dustry discussions, where the team identified the hicle in the 2020 time frame), and in the funding

TA01-6 DRAFT of CCDev for low-cost, conventional launch pro- with operation and cost of current systems while pulsion technologies by 2015. ARMD planning establishing research in the non-conventional sys- includes regular efforts in hypersonic tests and tems. Each of the technology challenges seen in technologies. These tests are critical for develop- Table 2 will be discussed in more detail in Section ing efficient hypersonic capabilities that support 2 of this roadmap report. access to space for small- and medium-class pay- loads, as these hypersonic air-breathing vehicles 2. Detailed Portfolio Discussion could be used as a first-stage booster for an upper- stage and payload. OCT’s investment in LPSTA 2.1. Portfolio Summary and Work is still to be determined, and this LPSTA roadmap Breakdown Structure provides an initial plan with options and candi- The LPSTA team assembled a work breakdown dates for future NASA technology funding. structure, referred to here as the Technology Area Reflecting the mission requirements and the Breakdown Structure (TABS) to organize the technology plans of the Agency, the LPSTA team technologies described in this section. This TABS, developed a representative launch vehicle manifest shown in Figure 2, concentrates on engines, mo- (seen in the second row of Fig. 1), with launch ve- tors, and other technologies capable of lifting pay- hicles categorized as: loads from the Earth’s surface to LEO, as well as These vehicle classes were used to generate rep- their associated propulsion-supporting subsys- resentative vehicle systems that supported mission tems. The top-level content represents a taxono- requirements. Launch propulsion technologies my based on the primary characteristics of pro- pulsion systems, and they differ in their range of Small: 0–2 t payloads technical and operational maturity. Chemical sol- id and liquid rocket propulsion systems have been Medium: 2–20 t payloads used since the dawn of space flight, and as their Heavy: 20–50 t payloads names suggest, consist of fuel and oxidizers in sol- id or liquid form. These technologies (as current- Super Heavy: > 50 t payloads ly used on the Space Shuttle and other vehicles) were then mapped to these vehicle systems. An are reaching the limits of theoretical efficiency and additional category was included for flight tests of performance using conventional propellants. Air- new launch vehicles, i.e., air-breathing launch breathing launch propulsion systems extract their propulsion. oxidizer from the atmosphere and could be part of an integrated system that includes more con- 1.4. Top Technical Challenges ventional rockets to reach the vacuum of space. LPSTA identified major technical challenges for Hypersonic air-breathing systems, as demonstrat- three time horizons, which reflect the needs and ed by X-43 and X-51, are still in the experimental expected successes in the near (present to 2016), stage. Improvements in ancillary propulsion sys- mid- (2017–2022), and long-term (2023–2028) tems would include the supporting subsystems for time frames. These technologies were prioritized conventional propulsion systems, including con- within each phase based on an LPSTA team con- trols and smaller rockets not directly responsible sensus for both the identified needs and the ex- for lift to orbit. Unconventional launch technolo- pected ROI for each technology area. This result- gies include systems that do not rely solely on on- ed in a balance of challenges that address problems board energy for launch or that use unique tech- Table 2. Top Technical Challenges by Time Frame. Present – 2016 2016 – 2022 2023 – 2028 1. High-Strength Oxygen-Compatible Materials 1. Large ORSC Engine 1. Hypersonic Technology Validation Flight 2. Integrated Ramjet/Scramjet Flight to Mach 7+ 2. ACES Integrated Flight System 2. High Energy Density Propellants 3. SRM Composite Case Damage Tolerance and 3. RBCC/TBCC Mode Transition 3. SRM Green Propellant Detectability 4. Nontoxic RCS 4. Advanced Expander Cycle Engine 4. Advanced Alt. Liquid Fuels 5. Advanced RP and Cryogenic MPS Components 5. MHD-Augmented Rocket 5. Nuclear Fusion NTR 6. TBCC Mach 4+ Turbine Acceleration 6. Large Scale, High Volumetric Efficiency Hybrid (1Mlbf Thrust.) 7. Hypervelocity Accelerators 7. Power Beaming Technologies and Propulsion Systems 8. Carbon-Carbon Nozzle (Domestic Source)

DRAFT TA01-7 Figure 2. Technology Area Breakdown Structure technology areas for launch propulsion. nologies or propellants to create rocket thrust. above. Key areas for improvement include a green Included in this area are technologies that are at propellant alternative to current oxidizers, ad- a very low TRL or that do not map into the oth- vancing the ability to assess damage tolerance lim- er propulsion taxonomies. The technology area its and detect damage on composite cases; devel- breakdown structure that focuses on these five ar- oping domestic sources for critical materials used eas can be seen in Figure 2. in manufacturing of SRMs, formulating advanced 2.2. Technology Description and hybrid fuels to get energy density equal to SRMs, Development Details and investing in the fundamental physics of SRM design including analysis and design tools. 2.2.1. Solid Rocket Propulsion Systems 2.2.2. Liquid Rocket Propulsion Systems (TABS 1.1) (TABS 1.2) Solid rocket motors (SRMs) have many ad- vantages over liquid systems such as high-ener- Liquid rocket propulsion systems use propel- gy density and long-term stability and storabili- lants (fuels and oxidizers) that are kept in a liquid ty. However several disadvantages that limit their state prior to and during flight. The advantages of liquid rocket engines include generally higher Isp applicability can be reduced or eliminated by ad- and better thrust control (including throttling and vancing the technology base of SRMs to make restart capability) than solids. Liquid rocket pro- them more attractive alternatives to liquid sys- pulsion systems are more operationally complex tems. Key disadvantages for SRMs today are low- than solids and require some form of active flow er performance (Isp), lack of throttling on demand or ability to shut down on command, environ- control that introduces additional possibilities for failures. The liquid propulsion roadmap addresses mental concerns, and ground operations costs as- the critical figures of merit by proposing technolo- sociated with safety issues in handling large solid gy investments in new liquid engine systems, pro- segments. This roadmap proposes technology in- pulsion materials research, high-density impulse vestments that address some of these disadvantag- and green propellants, and new subsystem mod- es, as well as enhance the advantages mentioned eling and design tools. TA01-8 DRAFT 2.2.3. Air-Breathing Propulsion Systems their supporting power supply and distribution (TABS 1.3) systems, large robust mechanical separation sys- Air-breathing launch propulsion systems obtain tems, and launch abort systems with high thrust the oxidizer for combustion from the Earth’s at- steerable motors tied to an adaptive flight control mosphere, which is combined with fuel brought system. These capabilities, once developed, would on board. Air-breathing engines change modes as have immediate positive impact on vehicle pro- speed and altitude increases, and transition to pure duction and operational costs, overall vehicle reli- rocket mode at high altitudes for the final ascent ability, and ground and flight safety. to space. This roadmap focuses on key technolo- 2.2.5. Unconventional/Other Propulsion gies that would advance air-breathing launch pro- Systems (TABS 1.5) pulsion systems during validation flight tests and Unconventional and other propulsion systems would lead to the design of a staged air-breathing include near, mid, and far-term technology ap- launch vehicle. These technology investments in- proaches primarily focused on reducing the cost clude the development of Mach 4+ turbines for of access to space. Ground-based, hypervelocity turbine-based combined cycles, long-duration accelerators for low-cost delivery of large numbers Mach 7+ scramjet operation, stable mode transi- of small, high-g tolerant payloads to LEO are a tions of rocket-based and turbine-based combined near-term technology that can provide significant cycle vehicles, an integrated air collection and en- payoff for a relatively small technology invest- richment system, and detonation wave engine op- ment. Orbiting space tethers that can act as the eration. final stage of a launch system and relieve the per- 2.2.4. Ancillary Propulsion Systems formance requirements for vehicle ascent, poten- (TABS 1.4) tially enabling fully-reusable, suborbital vehicles Ancillary propulsion systems that support the with robust operating margins at current technol- main vehicle propulsion system or provide oth- ogy levels, are a promising technology of interest er key launch vehicle functions during ascent, are in the mid-term. In the mid to far term, technolo- significant drivers in vehicle cost, complexity, and gies that can provide breakthrough improvements reliability. Development of new low-cost cryogen- in propulsion efficiency through the application ic and rocket propulsion (RP) valves, lines, and of energy generated by means other than chemical support components is essential to support less ex- combustion, such as power beaming, nuclear fu- pensive new vehicle development and reinvigorate sion, and high-energy density materials, are prime our nation’s technology base in this area. Some ca- candidates for future investment. pabilities that are within reach with up-front tech- 2.2.6. Technology Area Roadmaps and nology development include nontoxic reaction Table Descriptions control systems, advanced sensors coupled with The LPSTA technology tables identify figures of smart control systems providing robust integrat- merit and payload launch classes addressed. ed vehicle health management (IVHM), high- Production cost improvements would include powered electromechanical actuators (EMAs) and reducing vehicle manufacturing costs. Opera- Propulsion system production costs Small: 0–2 t payloads

Propulsion system operational costs Medium: 2–20 t payloads

Game-changing system and operational Heavy: 20–50 t payloads concepts

Game-changing propulsion system/ sub- Super Heavy: > 50 t payloads system efficiency and capability

National needs supported by input from Flight tests of new launch vehicles, other government agencies and industry e.g., air-breathing launch propulsion

DRAFT TA01-9 tional cost improvements would include reducing needs supported by input from other government personnel or infrastructure costs. Game-changing agencies and industry help multiple government system and operational concepts broadly expand or industry partners. space activities via higher mass or flight frequency. 2.2.6.1. Solid Rocket Propulsion Systems Game-changing efficiency and capability advances include improving individual vehicle or subsystem performance for more robust operations. National Solid Rocket Propulsion Systems Technology Roadmap. Technology Systems Propulsion 3. Solid Rocket Figure TA01-10 DRAFT 2.2.6.2. Liquid Rocket Propulsion Systems Liquid Rocket Propulsion Systems Technology Roadmap. Technology Systems Propulsion Rocket 4. Liquid Figure DRAFT TA01-11 2.2.6.3. Air-Breathing Launch Propulsion Systems Air-Breathing Propulsion Systems Technology Roadmap. Technology Systems Propulsion 5. Air-Breathing Figure TA01-12 DRAFT 2.2.6.4. Ancillary Propulsion Systems Ancillary Propulsion System Roadmap. System 6. Ancillary Propulsion Figure DRAFT TA01-13 2.2.6.5. Unconventional/Other Propulsion Systems Unconventional/Other Launch Technology Roadmap. Technology Launch 7. Unconventional/Other Figure TA01-14 DRAFT 2.2.7. Technology Area Tables 2.2.7.1. Solid Rocket Propulsion Systems

Table 3. Solid Rocket Propulsion System Technology Investments. Technology Investment Description TRL Major Challenges Path to TRL6 1.1.1 Propellants – New formulations for improved performance, environmental impact, and manufacturing processing HTPB Large Batch Mix/ Scale up HTPB production to a 4 Developing prebatch techniques Develop mix cycles at smaller scales, Pour Demo 1,800-gal propellant mix to pour that allow a full segment to be cast adapt a shorter mix cycle to a 1,800-gal- into a full-scale load test motor (approx. 13–15 mixes per segment). lon mixer, make several demonstration steel case 4-segment demonstra- mixes using shorter mix cycle, evaluate tor. data from test articles, and demonstrate effectiveness in full-scale motor firing. HTPB Continuous Mix/ Scale up to continuous mix with 3 Need large-scale continuous mix Demonstrate continuous mix process Pour Demo full-scale 4-segment steel case load facility, need mix process. on smaller scale, build large-scale mix test motor steel case demonstrator. facility, cast smaller motor using large Demonstrate quality assurance for continuous mix process, evaluate data new process to apply to human from test articles, demonstrate in full- rated systems. scale motor firing. AP Replacement Fundamental research into alterna- 2–3 Find replacement for ammonium Literature search, lab work, subscale test- Research tive high-energy solid propellants perchlorate (AP) that has adequate ing, large-scale testing. that can replace the current AP energy, density, & stability. used in today’s motors. High-Energy Density Develop subscale demonstrations 1–2 Need AP replacement (see above) Develop propellant using AP replace- Green Propellant Demo of promising candidates. and high-energy density ingredi- ment (see above) and high-energy den- ents. sity ingredients, demonstrate in full-scale motor firing. 1.1.2 Case Materials – Advanced case materials development, damage detection and repair techniques, handling process development to mitigate damage to large composite cases Composite Case Damage Develop damage tolerance limits 3 Detecting structural damage in the Evaluate alternative damage tolerance Tolerance & Detectability and methods for detecting damage fiber structure of composite cases. detection methods and assess against in large composite motor cases. representative damage samples, test against full-scale hardware, qualify processes for flight application. Large Composite Case Develop and demonstrate technol- 3 Moving and handling large compos- Assess risks in handling operations for Operations and Handling ogy for handling and operations ite structures without damaging the large composite cases, evaluate solutions Demo processing of large composite composite structure. for minimizing/eliminating risks, dem- cases. onstrate solutions in full=scale hardware demonstration. 1.1.3 Nozzle Systems – Advanced lightweight ablative materials, alternative nozzle designs Lightweight, Low- Develop and demonstrate new ad- 2–3 Formulation of new lightweight Research alternative materials. Erosion Nozzle Material vanced lightweight ablative nozzle materials. Evaluate candidates in subscale test rig. Demonstration materials for solid motors. Select most likely candidates for testing in large-scale demonstration.

1.1.4 Hybrid Rocket Propulsion Systems – High Propellant density material development with improved burn rate, combustion stability characterization/ design parameter understanding, upper stage multiburn motor High Volumetric Hybrid Hybrid motors do not have the de- 2–3 Fuel regression rates are typically Evaluate alternatives, test candidate sub- Propellant Technol- sired volumetric efficiency of solid ~10 times less for hybrids compared scale, test most promising alternatives in ogy Maturation (fuel/ motors. Develop and demonstrate to solids, with baseline HTPB fuels. large scale, develop scaling parameters, oxidizer/additives web advanced propellant formulations Need to examine burn rate additives demonstrate at 250,000 lbf and 1 Mlbf design work) and packaging concepts to im- or paraffin or different oxidizer flows thrust size motors. prove hybrid volumetric efficiency. or multiport multilayer configura- tions. Upper-Stage Variable Hybrids can be used for upper- 3 Multiple-use components will be For representative missions/applications/ Thrust/Multiburn Motor stage variable thrust/multiple-burn a large issue; getting sustained requirements, perform system studies applications. Currently selected programmable impulse out of the and develop candidate component solu- for use on Sierra Nevada’s Dream motor is another large issue. tions that can be used and then reused Chaser vehicle. multiple times, test at subscale and full scale as an integrated system. 1.1.5 Fundamental Solid Propulsion Technologies – Advanced design analysis tool development, validation through subscale solid test bed and cold flow testing Physics Based Model- A combination of computational N/A A consistent level of funding over Validating key physical models will lead ing Development and fluid dynamics (CFD) and analytical multiple years is required to develop to improved prediction and analysis Research computation tools must continu- and execute the test plans necessary capability. For example erosive burning, ally be improved to advance the to more fully understand the subtle which is currently treated as a liability, state of the art in designing and physics underlying SRM perfor- could be used to increase the perfor- analyzing solid rocket motors. Vali- mance. mance of an SRM. Time scales of when dating these tools requires a robust the models will be brought online are cold flow and small-scale solids test hard to predict, but if nothing is done, program. the models will not improve on their own.

DRAFT TA01-15 2.2.7.2. Liquid Rocket Propulsion Systems Table 4. Liquid Rocket Propulsion System Technology Investments.

Technology Invest- Description TRL Major Challenges Path to TRL6 ment

1.2.1 LH2/LOX Engines – High Isp, liquid hydrogen/liquid oxygen based engines for first or upper-stage propulsion J-2X Upper stage engine for Constella- 5 Nozzle extension materials and Development testing (to begin early tion Program manufacturing 2011)

SSME (RS-25) Derivatives Expendable derivative (RS-25E) 5 Manufacturing processes and Full-scale development testing of new Upper stage for heavy-lift vehicle 3 materials components Expendable derivative (RS-25F) 4 Integrated system interactions Manufacturing processes and materials Common Upper Stage Common upper-stage expander 4 Manufacturing processes Subscale demonstrators, full-scale Engine cycle engine for EELV. Materials development

High Reusability Engine Low-cost, high-reliability engine 3–4 Manufacturing processes Modeling of systems, subscale demon- Materials strators, full-scale development

1.2.2 RP/LOX Engines – High energy density kerosene-based engines for first stage lift Large Hydrocarbon High-thrust booster engine 3–4 Manufacturing Processes Modeling of systems, subscale demon- Engine Materials strators, full-scale development Combustion instability

High Reusability Engine Low-cost, high-reliability engine 2–3 Manufacturing Processes Modeling of systems, subscale demon- Materials strators, full-scale development

1.2.3 CH4 Engines – Alternative hydrocarbon engines with high energy density and Isp Methane Upper-Stage Development of technologies to 3 Ignition Subscale demonstrator, full-scale dem- Engine support high-altitude start and Manufacturing processes onstrators

operation of LOX/CH4 engine Materials

Methane Booster Engine Development of technologies to 3 Ignition Subscale demonstrators, full-scale

support operation of LOX/CH4 Manufacturing Processes demonstrators engine. Materials 1.2.4 Detonation Wave Engines (Closed Cycle) – produce thrust by igniting fuel and oxidizer through a series of controlled detonation waves Closed Cycle Detonation Detonation wave engines produce 3 Ignition Modeling of systems, subscale demon- Wave Engine thrust by igniting fuel and oxi- Manufacturing processes strators, full-scale demonstrators dizer through a series of controlled Materials detonation waves. In a closed cycle Cooling oxidizer is supplied by the vehicle. 1.2.5 Propellants – Propellant research involves application of nontoxic green propellants, high-energy combinations of fuels and oxidizers

Propellant Densification Propellant densification delivers 5 Ground Support Equipment & LOX demonstration on Taurus II, LH2 enhanced vehicle mass fraction LOX Processes demonstrated in test only performance 4–5

LH2 Alternate Hydrocarbon Demonstration of fuels for rocket 3–5 Performance characterization Subscale demonstrators, full-scale Fuels applications and green propellants demonstrators

Alternate Oxidizers Demonstration of alternate oxidiz- 3–5 Performance characterization Subscale demonstrators, full-scale ers demonstrators

Strained Ring Hydro- Isomers of existing hydrocarbons 3 Low-cost, high-yield production. Production R&D, combustion tests, carbons with novel arrangements of the subscale demonstrators, full-scale atoms and increased bond energies, demonstrators

resulting in an expected Isp increase Gelled Propellants Gelled propellants provide com- 2–4 Performance characterization Modeling of systems, subscale demon- parable density impulse to solid strators, full-scale demonstrators propellant systems while delivering the mission flexibility of a liquid system while demonstrating greater operational safety. Metalized Propellants Fuels with suspended metal pow- 2–4 Performance characterization Modeling of systems, subscale demon- ders or nano particles strators, full-scale demonstrators

TA01-16 DRAFT Technology Invest- Description TRL Major Challenges Path to TRL6 ment 1.2.6 Fundamental Liquid Propulsion Technologies – Technologies enabling advances in liquid rocket engine launch propulsion including advanced engine design and modeling tools, advanced materials, new nozzle technologies, combustion physics research, and advanced turbomachinery components Combustion Physics Fundamental physics modeling of N/A Obtaining sufficient test data to an- Modeling of systems, subscale demon- combustion processes chor developed models and codes. strators

Advanced Nozzle Design, modeling, and demonstra- N/A Manufacturing processes Modeling of systems, subscale demon- Concepts tion of advanced nozzle concepts Materials strators

Advanced Design Tools Development and validation of ad- N/A Obtaining sufficient test data to Modeling of systems, subscale demon- vanced design and modeling tools anchor predictive analysis models strators and codes. Propulsion Materials Modeling and demonstration of N/A Manufacturing processes Modeling of systems, subscale demon- advanced materials Materials strators

Advanced Turbomachin- Modeling and demonstration of N/A Manufacturing processes Modeling of systems, subscale demon- ery Components advanced turbomachinery com- Materials strators ponents

2.2.7.3. Air-Breathing Launch Propulsion Systems Table 5. Air-Breathing Propulsion System Technology Investments. Technology Invest- Description TRL Major Challenges Path to TRL6 ment 1.3.1 Turbine-Based Combined Cycle (TBCC) – Multiple propulsion modes starting with a turbine-based engine, transitioning with increases in speed to ramjet mode, scramjet mode, and finally to rocket mode TBCC Flow Path Con- Ensure stable operation of propul- 4 Controlling proper fuel/air mixture; Conduct tests on flow path-induced troller sion system flow paths while maxi- control mass and speeds of inlet air thrust fluctuations

mizing vehicle Isp and thrust to multiple inlets

TBCC High-Mach # Operate turbine engines to Mach 3 Need compressor, combustor, and Test high-temperature engine compo- Turbine Acceleration 4 and pursue Mach 6 turbine ac- turbine designs and materials that nent designs and materials, test Mach celeration withstand high temperatures; thrust 4+ augmenter performance, perform augmenter designs Mach 4 turbine ground and flight tests, investigate cooling to achieve Mach 6 turbine acceleration TBCC Inlet Optimization Initiate stable flow in multiple- 4 Proximity of inlet systems leads to Test simultaneous inlet functioning, speed inlets (for turbine, ram/ flow coupling effects test thermal choking and positioning scramjets and rockets) of the flow shock structures, test inlet geometries TBCC Turbine/Scramjet Maintain vehicle propulsive thrust 3 Transitioning operation from one Verify stable turbine flow path opera- Mode Transition during sequence of turbine engine propulsion mode to another while tion leading to stable ramjet/scramjet shutdown and initiation of ramjet/ maintaining thrust ignition, test stable turbine shutdown scramjet combustion methods, determine safe thermal environment 1.3.2 Rocket-Based Combined Cycle (RBCC) – Multiple propulsion modes starting with a ducted engine (an ejector ramjet) to augment the airflow until the vehicle reaches suitable speeds at which point it transitions to ramjet mode, scramjet mode, and finally to rocket mode RBCC Ejector Thrust Supply increased mass flow to allow 3-4 Providing sufficient entrainment Test ejector geometries and map flow Augmentation engine to operate at low supersonic and mixing of air with rocket plume field speeds for increased low-speed RBCC performance RBCC Mode Transition Maintain vehicle propulsive thrust 3 Transitioning operation from one Verify ejector flow path operation lead- during sequence of ejector mode mode to another while maintaining ing to stable ramjet /scramjet ignition, shutdown and initiation of ramjet thrust determine safe thermal environment combustion RBCC Plug Nozzle Maintain efficiency at a wide range 3 Plug nozzle shape and characterizing Perform research to determine optimum of altitudes interaction of plug with flow path plug nozzle shapes and map flow proper- ties around nozzle RBCC Dynamic Inlet/ Initiate stable flow in multiple- 3-4 Proximity of inlet systems leads to Test simultaneous inlet functioning, Nozzle Optimization speed inlets and nozzles (for ejector, flow coupling effects; nozzle sizing test thermal choking and positioning of ram/scramjets and rockets) the flow shock structures, test inlet and nozzle geometries 1.3.3 Detonation Wave Engines (Open Cycle) – Acceleration achieved by igniting fuel and oxidizer through a series of controlled detonation waves, employ- ing an open cycle where oxidizer is obtained from the atmosphere Detonation Wave Engine Inject and mix fuel and oxidizer at 3–4 Timing of propellant injection and Test injector architectures, test mixing Fuel/Oxidizer Injection optimum rates and amounts mixing is critical for reactions to methods and Mixing occur

DRAFT TA01-17 Technology Invest- Description TRL Major Challenges Path to TRL6 ment Detonation Wave Engine Start detonation reaction in a con- 3–4 Controlling ignition; reduce noise; Test detonation ignition techniques, Ignition Control trolled manner dampen pulsed operation vibration study noise levels and research methods for reducing noise, develop vibration dampening technologies Pulsed Detonation Wave Use detonation waves (in pulsed- 3–4 Timing injection, mixing and ignition Test timing sequencing, integrate Engine mode operation) to combust fuel pulses; reducing vibration and noise propulsion/ airframe for low- and high- and oxidizer speed flight tests

Continuous Detonation Use detonation waves (continuous 2-3 Controlling ignition and wave Research and test inlet flow speed reduc- Wave Engine operation) to combust fuel and propagation; cooling; reducing inlet tion methods, integrate propulsion/air- oxidizer flow speeds frame for low and high-speed flight tests

1.3.4 Turbine Based Jet Engines (Flyback Boosters) – Turbine engines modified to handle the stresses of launch and reentry that are able to fly a launched vehicle back to the launch site Flyback Engine Alterna- Demonstrate alternative fuels for 4–5 Ability to provide high energy Flight test alternative fuels tive Fuels commonality with existing rocket content; able to absorb heat; thermal propellants stability

Flyback Engine Vibra- Reduce potential engine damage 3 Dampening vibration on engine dur- Develop and flight test vibration damp- tion during launch ing high-speed flyback ening technologies

Flyback Engine Reduced Reduce amount of fuel needed to 3-5 Finding fuels with increased energy Research, develop, and flight test Fuel Consumption operate flyback engine content; increase efficiency of com- methods to reduce flyback engine fuel bustion. consumption

1.3.5 Ramjet/Scramjet Engines (Accelerators) - Ramjets ingest atmospheric air at the engine inlet at high speeds and compresses it; air is then slowed to subsonic speeds, at which point it is combined with fuel for combustion. Scramjets compress and ignite air at supersonic speeds Ramjet/Scramjet Accel- Increase ramjet and scramjet com- 3–4 Optimizing timing of injection, Data review of previous flight tests and eration Combustion bustion performance and achieve mixing, igniting, and burning; main- continued flight tests of ramjet/scramjet effective combustion over a wide taining sustained operation with combustion studies speed range high-combustion temperatures Alternative Ramjet/ Research alternative fuels for ramjet 2–3 High energy content; ability to Flight test alternative fuels, certify fuels Scramjet Fuels and scramjet operation achieve effective combustion over a wide speed range; ability to heat- sink; thermal stability Reduced Ramjet/ Allow ramjets and scramjets to 2–3 Profile inlet boundary layer and Research and test inlet geometries Scramjet Inlet Speeds begin operation at lower speeds shock interactions; determine lead- allowing lower inlet speeds, study inlet ing edge and inlet flow path shapes flow-field physics

High-Temperature Employ seals that survive under 3 High-temperature tolerance Research and test seal materials and Ramjet/Scramjet Seals high temperatures mechanisms

Lightweight Ramjet/ Sc- Employ heat exchangers made from 3 Developing efficient and lightweight Research and test lightweight heat ramjet Heat Exchangers lightweight materials heat exchangers able to operate un- exchangers der ramjet/scramjet flight conditions

Ramjet/Scramjet/ Integrate the propulsion geometry 3–4 Designing overall vehicle to combine Review past flight test data and refine Propulsion/ Airframe with the vehicle airframe optimal propulsion performance propulsion/airframe geometry in contin- Integration with most effective airframe size ued flight tests

1.3.6 Deeply-Cooled Air Cycles – Cryogenic liquid hydrogen fuel is used to cool or liquefy incoming air from the engine inlet; air is then combusted with the liquid hydrogen to create thrust Deeply-Cooled Air Cycle Increase efficiency of heat exchang- 3 Increase heat transfer coefficient; Heat exchanger design, fabrication, Heat Exchangers ers used during deeply-cooled air design compact, lightweight heat verification and flight test cycle process exchanger

Lightweight and Ef- Liquefy air collected from the atmo- 3 Reduce weight of air liquefier system Research and test lightweight materials ficient Air Liquefier sphere to be used as oxidizer for air liquefiers

1.3.7 Air Collection & Enrichment Systems (ACES) – Liquid oxygen (LOX) is generated by separating it from the atmospheric air, which allows vehicles to take off without LOX on board, minimizing takeoff weight Low-Mass Air Extraction Extract air during high-altitude 3 Extract adequate amount of air Low-mass air extraction research, design, flight for ACES operation in reasonable fabrication, verification, and flight test amount of time at high altitudes Rotational Fractional Generate LOX by the separation and 4 Efficient distillation operation under Create ground demonstrator of rota- Distillation distillation of high pressure air (at its g-forces tional fractional distillation unit, flight dew point) test unit

TA01-18 DRAFT Technology Invest- Description TRL Major Challenges Path to TRL6 ment ACES Heat Exchangers Increase efficiency of heat exchang- 3–4 Increase heat transfer coefficient; Heat exchanger design, fabrication, ers used during air collection and design compact lightweight heat verification and flight test enrichment process exchanger ACES Integrated System Combining ACES subsystems into an 2–3 Maturing ACES subsystems; perform- Complete ACES system integration and operational system ing integrated system analysis transient ACES operational analyses; produce integrated system and flight test 1.3.8 Fundamental Air-Breathing Propulsion Technologies – Technologies facilitating air-breathing launch propulsion system development High-Fidelity Integrated Develop high-fidelity models and N/A Increasing accuracy and speed of Continued software research, develop- Propulsion Design design software for hypersonic model computations; increasing ment, test and validation with hardware Software propulsion systems fidelity of design software systems

High-Temperature Develop materials capable of N/A Advanced material synthesis; Research, develop, and test high-temper- Ceramic Composites withstanding high temperatures material interaction with extreme ature ceramic composites experienced in hypersonics environments (e.g., temperature, corrosion); physical and structural property characterization Carbon-Carbon Nozzles Develop lightweight, high-temp N/A Increasing carbon-carbon strength Research, develop and test carbon- carbon-carbon based nozzles under compression and shock carbon nozzles

Advanced Propulsion Develop advanced propulsion ther- N/A Designing thermal management Evaluate and test integrated thermal Thermal Management mal management systems capable systems that can adapt to diverse management systems operating under of supporting vehicle operation temperature ranges transient and continuous heat and cool- under varied temperature ranges ing loads Actively Cooled Inlets/ Develop techniques for cooling N/A Integrating materials and working Evaluate and test active cooling inlet/ Nozzles propulsion components using the fluid without adverse effects to nozzle concepts working fluid materials, working fluid, or propul- sion system

2.2.7.4. Ancillary Propulsion Systems Table 6. Ancillary Propulsion System Technology Investments.

Technology Invest- Description TRL Major Challenges Path to TRL6 ment 1.4.1 Auxiliary Control Systems (ACS) – These systems provide roll control for single-engine first stage ascent, as well as full upper-stage attitude control during stage separation and coast using small thrusters for propulsive force to rotate the vehicle about the roll, pitch, and yaw axes. Low-Cost, High Thrust Current RCS mono-prop or bi-prop 4 Low leakage for extended propellant Propellant exposure testing, demon- to Weight Ratio Reaction systems are very costly. New ma- exposure strate new production techniques Control Systems (RCS) terials and production techniques could reduce thruster cost, as well as reduce the weight of the support systems. Non-Toxic RCS Nontoxic RCS propellants can re- 4–5 Propellant material compatibility Material compatibility testing, demon- duce ground infrastructure cost and strate repeatable, consistent ignition and complexity, improve ground safety Small/lightweight cryogenic lines combustion stability and operational timelines, as well as and valves potentially reduce flight vehicle sys- tem production costs and improve performance. Work has been done already for various bi-prop alterna-

tives like LOX/methane, LOX/LH2, LOX/ethanol, and GOX/methane. Hydroxl Ammonium Nitrate (HAN) and Ammonium Dinitramide (ADN) are promising monopropellant alternatives. Composite Overwrap Develop understanding of root 2 Material properties understanding Applied research into physical properties Pressure Vessel (CoPV) cause of stress rupture and fine tune and initiation of stress rupture, develop advances to reduce design without oversizing the tank. lower weight designs based on this data stress rupture This would permit a reduced safety factor, resulting in lighter weight tanks. Advances in CoPV technol- ogy also could be applied to MPS applications.

DRAFT TA01-19 Technology Invest- Description TRL Major Challenges Path to TRL6 ment 1.4.2 Main Propulsion Systems (MPS) – Subsystems that provide propellant conditioning and feed, tank pressurization, and purge supply to the engine use insulated lines and components for cryogenic applications Advanced, Low-Cost Evolutionary development of 4 Maintaining low mass Design for cost, reliability, and reusabil- Cryogenic and RP Com- robust, low cost fill and drain, ity, demonstrate production capability at ponents recirculation, and engine isolation Design simplification for production reduced cost valves, ducts, recirculation pumps and cryogenic helium regulators for expendable and reusable launch vehicles using materials advances and improved production methods would greatly reduce production costs and improve reliability for reusable applications. 1.4.3 Launch Abort Systems – Propulsive systems for pulling spacecraft away from the launch vehicle in the event of a launch failure Vectorable High-Thrust High-thrust abort motor designs 4 Development of the high peak Demonstrate integration of the TVC Abort Motor with vectorable thrust enable im- power batteries (i.e., thermal bat- system with the motor cases proved launch abort vehicle control teries that would be acceptable to through all flight regimes. High- NASA) for TVC use thrust TVC also requires high slew rate, high slew angle, high thrust (50,000–150,000 lbf) solid propellant motors and associated systems. Adaptive Flight Control Automated flight controls for launch 2 Lightweight, minimal volume for self Demonstrate capability of system sized abort vehicles (e.g., at a minimum contained LAS flight control system to fit within available LAS constraints as an outer loop around a more conventional flight controller) would address the uncertainty inherent in abort scenarios and improve abort system reliability over a wide range of operating and environmental conditions. Liquid Propellant Inte- Liquid propulsion systems capable 1 Fast-response, high-pressure, mid- Maturation of associated components in- grated Abort System of providing both the high thrust thrust (3,000–5,000 lbf) propulsion cluding high-pressure tanks, regulators, required for vehicle abort and low systems, with variable thrust/sec bi-propellant valves, and the thruster thrust required for on-orbit maneu- (throttleable or pulse modulated) itself are needed vering and attitude control from an development integrated package. 1.4.4 Thrust Vector Control (TVC) Systems – Actuators that adjust the direction to the exhaust gas plume to provide vehicle steering Non Toxic Turbine Power Develop replacement for hydrazine- 4 Integrated vehicle impacts Initial development of options, demon- Units for Hydraulic Pres- driven hydraulic power units using stration tests surization either nontoxic propellant or a blow-down type system.

Advanced Actuator Advance state of the art of electro- 3 Fault tolerance Demonstrate robust operation with fault Development (EHA, hydrostatic and electromechanical tolerance EMA, IAP) actuators as well as an integrated Power draw actuator pack¬age for use on a wide range of launch vehicles especially RLVs for simpler, lower cost inte- grated TVC systems. Corona-proof, Rapid Advanced actuators will require 3 Lightweight shielding Provide sufficient environmental testing Charge/Discharge High greater electrical power from a high- for shielding development Power Battery & Power voltage, rapid-discharge battery Robust battery Distribution Systems & distribution system. This system must be developed to avoid corona effects during ascent. 1.4.5 Health Management & Sensors – Propulsion system instrumentation and associated avionics architecture that monitor propulsion system health Evolutionary Diagnos- Develop advanced sensors for all 3 Extreme environments Environmental testing, demonstrate tic/ Prognostic Sensor ancillary applications for use in integrated function with hardware devel- and Monitoring System ground processing and flight to im- Signal processing bandwidth opment Development prove hardware life as well as fault detection and isolation. Includes cryogenic & hypergolic liquid level sensors, flowmeters, leak detection sensors, extreme environment sen- sors, & rotating machinery sensors using advances in fiber optic, Piezo- electric, Microelectromechanical & nanosensor technology.

TA01-20 DRAFT Technology Invest- Description TRL Major Challenges Path to TRL6 ment Continuously Advance Continue to develop, flight qualify, 2–3 Extreme environments Environmental testing Flight Environments and implement add-on flight in- Characterization strumentation (sensors to monitor Power restrictions strain, temperature, vibration, acoustics, etc., along with associated power, data acquisition, and wireless communication technologies for flight environments) that can pro- vide the necessary environmental information to verify, and potentially optimize designs of launch vehicle propulsion systems. 1.4.6 Pyrotechnic and Separation Systems – Linear-shaped charges or frangible bolts are typically used for stage separation Fully Redundant Separa- Demonstrate, first through ground 2–3 Vehicle system interactions due to Model system, design prototype, ground tion Subsystem testing and then later in flight, dual pyro shock loads test, update model and prototype redundancy for stage separation whether the separation subsystem uses a linear shaped charge or a frangible type joint to increase safety. Purely mechanical sepa- Develop minimal weight highly reli- 3–4 Minimizing weight penalty for purely Load requirements, prototype system, ration subsystem able mechanical stage separation mechanical system and scale-up to lab test, flight test system for medium and large launch large systems vehicles. Eliminating pyrotechnic separation systems would eliminate pyro shock concerns for nearby flight hardware and simplify produc- tion and ground processing. 1.4.7 Fundamental ancillary propulsion technologies basic technologies that would apply to the all the various ancillary systems Advanced Materials Critical to advances for all ancillary N/A Material Compatibility Implement advances into component Development systems. Material improvements design advance the state of the art by reducing weight and/or cost. High-Fidelity Predic- Improved models with predictive N/A Obtaining sufficient test data to an- Develop and refine codes based on ap- tive Capabilities for capability, anchored with appropri- chor developed models and codes. plicable test data Aerodynamics, Loads & ate test data, would greatly benefit Environments, & Flight MPS, ACS, TVC, and LAS develop- Control ment by providing a large reduction in model uncertainty as well as reductions in development time and cost. Comprehensive Py- Develop comprehensive pyrotech- N/A Adequate characterization of com- Generate performance database, de- rotechnic Component nic component computer modeling ponent performance velop model, anchor with test Modeling Tool tool, anchored with testing, to reduce the development cost and schedule impact of new pyrotechnic component designs.

2.2.7.5. Unconventional/Other Propulsion Systems Table 7. Unconventional/Other Propulsion System Technology Investments. Technology Invest- Description TRL Major Challenges Path to TRL6 ment 1.5.1 Ground-based Launch Assist – Applying a method of accelerating a vehicle horizontally or vertically to give it a higher initial velocity and to reduce the amount of propellant required to reach orbit Combustion Gas Cata- Combustion gas launch assist is a 3–4 High-volume gas generation capa- Tests to incrementally increase launcher pult (Low Speed) pneumatic hot gas system derived bilities. High transient thermal and length and velocities, vehicle separation from mature aircraft carrier steam- mechanical stresses. Low main- tests catapult technology. Assist veloci- tenance seals. Vehicle separation ties would range from subsonic to dynamics. transonic. Maglev Catapult (Low Magnetic levitation techniques are 3–4 Scaling to large vehicle masses. Energy storage and power switching Speed) used to support and accelerate a Energy storage and power switching. R&D, subscale system demo, including vehicle for horizontal launch assist. Vehicle separation dynamics. sep testing Assist velocities would range from subsonic to transonic. Hydrogen Gas Gun A large-bore gun that accelerates a 3 Hydrogen pressurization. Projectile Hydrogen pressurization system design (Hypervelocity) payload/rocket stage along the bar- integrity. and test, subscale system demo rel through the rapid expansion of hydrogen gas from a high-pressure reservoir.

DRAFT TA01-21 Technology Invest- Description TRL Major Challenges Path to TRL6 ment Blast Wave Accelerator The blast wave accelerator uses 3 Projectile and launcher integrity. Detonation testing, projectile acoustic (Hypervelocity) rings of high explosives inside a Timing of sequential detonation tests, subscale system demo long tube that are sequentially and detonation uniformity. In-bore detonated to accelerate a payload/ stability. rocket stage. Ram Accelerator The ram accelerator consists of 3 Erosion of the projectile and tube. Laboratory experiments at in-tube Mach (Hypervelocity) a long, sealed tube filled with a Premature fuel detonation in front of 6–10, and ultimately velocities of 6–8 mixture of fuel and oxidizer, such as of the projectile. Greater than Mach km/s, subscale system demo hydrogen and oxygen. A projectile 6 in-tube, supersonic combustion. resembling the center body of a Large, fast-acting valves. ramjet is shot into the tube, igniting the mixture and blasting the projec- tile down the tube, which acts like the outer cowling of a ramjet. Electromagnetic Gun A railgun consists of a pair of copper 3–4 Power requirements. Structural in- Energy storage and power switching (Hypervelocity) rails, mounted in an insulating bar- tegrity of projectile and launcher. Rail R&D, plasma armature R&D, rail erosion rel, with the rails connected to a rap- erosion and life. Energy storage and tests, subscale system demo idly switched high current source. power switching. Plasma armature An armature on the projectile to be performance. fired completes the circuit, resulting in a magnetic force that drives the projectile down the barrel. Mechanical Accelerator Typified by the Slingatron concept, 3–4 Structural integrity of the system. Structural design, stress and vibration (Hypervelocity) it consists of a long tube arranged Friction in the interior of the spiral analysis. Testing of techniques to reduce in a spiral pattern which accelerates tube. Projectile integrity. tube friction. Subscale system demo. a small payload to orbital velocity by gyrating the tube assembly in an oscillatory pattern. Acceleration of the payload is by centripetal forces. 1.5.2 Air Launch/Drop Systems – Space launch vehicles carried to the upper atmosphere by a carrier aircraft Large Subsonic Stage Stage launch vehicle from top or 5 Increasing aircraft lift capabilities. High-lift device R&D, configuration R&D, bottom of very large (jumbo jet- Stage separation dynamics. Large, separation simulations and subscale class) subsonic carrier aircraft. twin fuselage configuration. testing Supersonic Stage Stage launch vehicle from carrier 5 Mated configuration drag. High-q Low-drag config. R&D, subscale sep tests aircraft at supersonic speeds. stage separation.

1.5.3 Space Tether Assist – Space-based tethers using momentum exchange to accelerate payloads from suborbital to orbital velocities, reducing require- ments for launch vehicle ascent performance Hanging Tether A gravity-gradient stabilized tether 2–3 Tether life in LEO environment. High-speed reel demo, flywheel ground that reaches down to the upper High-speed tether reel-in and reel- demo, orbital electrodynamic tether atmosphere from orbit (e.g., Sky- out. Flywheel energy storage. Rapid propulsion demo, subscale orbit demo, hook). Payloads are delivered to the payload capture mechanism. Robust including P/L capture bottom of the tether by a suborbital tether dynamics modeling. vehicle, then transported up along the tether and released into orbit. Rotating Tether A tether that rotates or spins in the 2–3 Tether life in LEO environment. Reli- Flywheel ground demo, orbital elec- plane of its orbital motion (e.g., able tether deployment. Flywheel trodynamic tether propulsion demo, sub- Rotovator or Bolo). Payloads are energy storage. Rapid payload cap- scale orbit demo, including P/L capture delivered to the tether by a subor- ture mechanism. Robust modeling of bital vehicle and are transferred into tether dynamics. orbit by the rotation of the tether and an exchange of momentum. 1.5.4 Beamed Energy / Energy Addition – Ground-based laser, microwave, or other focused electromagnetic radiation to heat air at the base of a vehicle, or the propellant carried onboard, to produce propulsion at high efficiencies Microwave/Laser Microwaves or lasers beamed from a 2–3 Very large power transmitters (GW- Power beaming and tracking tests, heat Thermal Rocket ground or space station are directed class), accurate tracking, efficient exchanger R&D, small-scale flight demo at a heat exchanger mounted on a energy conversion, and thermal vehicle to heat stored propellant management. and create thrust via a thermal

rocket, achieving Isp from 600 to 900 sec. Laser Lightcraft A pulsed laser from a ground station 2–3 Very large power transmitters (GW- Power beaming and tracking tests, small- is used to heat atmospheric air, or class), accurate tracking, efficient scale flight demo, all propulsive modes onboard propellant, and rapidly energy conversion, and thermal expand it against a focused pusher management. plate on the vehicle, generating thrust. MHD-augmented Magnetohydrodynamic (MHD) 2–3 Power requirements. Mass efficiency Power systems R&D, low-mass compo- Rocket effects can be used to further accel- of system components. Thermal nent development and test, ground erate the exhaust products of a con- management. engine tests ventional chemical rocket engine to achieve significantly higher levels of thrust and Isp (1,000 – 2,500 sec).

TA01-22 DRAFT Technology Invest- Description TRL Major Challenges Path to TRL6 ment 1.5.5 Nuclear - Using nuclear fission or fusion reactions for high propulsive performance. Advanced Solid Core A nuclear thermal rocket (NTR) that 2 Lightweight, robust, high-tempera- Core material and manufacturing R&D, Fission NTR uses an advanced solid-core nuclear ture core with low pressure drop and rad shielding R&D, component tests, fission reactor. The reactor employs high surface area. Radiation shield- ground engine tests fine alloy fibers arranged in a lattice ing. Accident hazard containment. for greatly improved heat transfer to the propellant and increased Isp (>1,000 sec) with reduced mass. Liquid & Gaseous Core Thermal rockets that use liquid- or 2 Nuclear criticality, radiant heat Analysis and lab testing, rad shielding Fission NTR gaseous-core nuclear fission reac- transfer, and fuel containment. R&D, component design and testing, sys tors. These would operate at very Radiation shielding. Accident hazard grnd demo high temperatures, potentially containment. enabling Isp of 3,000–5,000 sec. Fusion NTR A thermal rocket that uses a fusion 2 Device size to achieve power break- Scaled-up reactor tests, continuous reac- reactor. Concepts for achieving even. Control of ion and electron tor operations demo, component design clean aneutronic fusion include feeds. Structure and cooling. Drive and testing, sys grnd demo Inertial Electrostatic Confinement, current/ voltage. Magnetic field drive Inertial Electrodynamic Fusion, and (for IEF). Dense Plasma Focus. Performance is generally similar to fission NTR. External Pulsed Plasma External pulses generated by 2 Type of pulse unit, its degree of Pulse unit R&D, detonation testing, successive detonations of nuclear collimation, detonation position and plasma interaction tests, subscale flight material are used to generate fissile bum-up fraction. Pulse unit demo propulsion by the action of plasma safety and loading. Pusher plate- expanding against a pusher plate plasma interaction. at the rear of the vehicle. (Isp of 5,000–10,000 sec). Low-Energy Nuclear A thermal rocket that uses a reac- 1 Development and validation of LENR process research, experimentally Reactions NTR tor that operates on Low Energy underlying LENR predictive theory. initiate and control LENR, component Nuclear Reactions (LENR), a form of Demonstration of controlled reac- design and testing, sys grnd demo “cold fusion.” Performance would tions. be similar to other NTR approaches, but without the radiation hazards. Nuclear-based Com- The energy from nuclear reactions is 2 Challenges are similar to those of Analysis and lab testing (including wind bined Cycle applied in a combined cycle propul- conventional TBCC and RBCC systems tunnel tests), rad shielding R&D, compo- sion system with both air-breathing and advanced NTR, but include nent design and testing, sys grnd demo, and rocket modes of operation. Spe- integration of a nuclear reactor into flight demo cific impulse values in air-breathing an air-breathing flow path. mode are essentially infinite. 1.5.6 High Energy Density Materials/Propellants – Propellants or materials that contain considerably higher stored energy per mass than conventional chemical propellants Polynitrogen New liquid or solid compounds of 2 Stability/shock sensitivity, produc- Formulation R&D, production R&D,

nitrogen, such as N4 or N8, which tion, and storage. stability tests, propulsion demos release very high energy upon

decomposition into N2 molecules, potentially enabling Isp of 350–500 sec. Nanopropellants Propellants with embedded 2 Controlled energy release. Consis- Production R&D, combustion/ stability nanoscale particles of combustible tently reproducible properties. tests, propulsion demos material (e.g. aluminum powder), providing greater reactive surface area and energy. Atomic and Metastable Very high-energy propellants that 2 Stability/shock sensitivity, produc- Production R&D, energy release and contain atomic free-radicals or tion, and storage. stability tests, propulsion demos metastable forms of molecules, such as atomic hydrogen, metasta- ble helium, and metallic hydrogen.

Potential for Isp > 2,000 sec.

3. Interdependency With cluding bodies with atmospheres, both for robot- Other Technology Areas ic sample return and for safe and assured return of The launch vehicle propulsion technology area humans. Many of the technology challenges fac- has many interdependencies and synergies with ing launch vehicle propulsion systems are com- many of the other technology areas. (If a TA is not mon to the ones facing this TA. listed, no significant interdependency was identi- Space Power and Energy Storage Systems – fied.) Among them are: There are several propulsion systems like beamed In-Space Propulsion – Most of the fundamen- energy that use high-power electrical storage and tal tools, rocket propulsion, and nonrocket (teth- distribution systems, which are synergistic with er) propulsion systems have direct synergy with this TA. Nuclear propulsion systems are also con- the in-space propulsion area. This is particular- sidered synergistic with this TA in the area of pow- ly true for launches from planetary surfaces, in- er generation. DRAFT TA01-23 Robotics, Tele-Robotics, and Autonomous 4. Possible Benefits to Systems – Fault detection, isolation, and recovery Other National Needs capabilities as well as prognostic/diagnostic capa- In addition to supporting NASA goals for space bilities in this TA are synergistic with IVHM tech- exploration and the achievement of routine, low nology. cost access to space, the advancement of launch Scientific Instruments, Observatories, and propulsion technologies supports national needs Sensor Systems – Sensor technologies related to as a whole. These needs include those of oth- cryogenic or high-temperature applications are er government agencies, such as the military, the highlighted in this TA and the LPSTA and are national security community, and NOAA, which synergistic. would benefit greatly from the reduced costs, Entry, Descent, and Landing Systems – Tech- improved reliability, and greater utility of new nologies for reaction control systems and reentry launch systems enabled through advanced propul- propulsion are synergistic with this technical area. sion technology. Similarly, the success and com- Nanotechnology – Many areas of nanotechnol- petitiveness of the commercial launch industry ogy, including low-weight, high-strength and/or would be greatly enhanced through the creation high-temperature materials, sensors, propellants, of more efficient and cost effective launch propul- coatings, and insulation directly feed into launch sion systems. The President has tasked NASA with vehicle propulsion applications. This is an interde- helping the nation sustain and expand its world pendent technical area. leadership in aerospace technology, which in turn Modeling, Simulation, Information Technol- provides many spinoffs to other industries and a ogy, and Processing – We share interdependency major opportunity to reinvigorate STEM educa- with this TA, as fundamental design and analysis tion. The President’s current budget proposal also tools are needed for engine component and sys- emphasizes developing the commercial launch in- tem development and test. dustry. This could lead to the establishment of Materials, Structural and Mechanical Sys- new, emerging markets for an active and aggres- tems, and Manufacturing – Many areas of this sive entrepreneurial launch industry. TA, including low-weight, high-strength, and/ Over the last decade and a half, the U.S. aero- or high-temperature materials, sensors, coatings, space industry has been significantly impacted by and insulation as well as manufacturing process- the lack of investment in launch propulsion tech- es would directly feed into launch vehicle propul- nologies. This has caused the U.S. to lose several sion applications. This is an interdependent tech- key technology capabilities that enable access to nical area. space. Some critical aspects of our ability to ac- Ground and Launch Systems Processing – cess space rely on foreign suppliers, e.g., ORSC There are both synergies and interdependencies engines, which put restrictions on the use of their between LPSTA and this TA. Sensor development supplied technologies. These restrictions have a for ground applications is synergistic with propul- significant impact on national security and de- sion applications particularly for cryogenic sys- fense, and they can only be addressed by creating tems. The LPSTA and this TA are interdependent a national supply base for these critical compo- regarding IVHM technology development. nents and technologies. Thus, any investment in Thermal Management Systems – In general, propulsion technology will help to offset this loss, thermal management is a critical need for launch will help establish a basis on which to reinvigo- propulsion systems. While we do share synergy rate the fundamental LPSTA capability, and will with this TA regarding cryogenic insulation tech- re-grow technological “seed corn” for the future. nologies, propulsion systems could share inter- dependency with this TA if they broadened their scope to include propulsion-specific applications.

TA01-24 DRAFT Acronyms HLPT Heavy Lift Propulsion Technology ACES Air Collection and Enrichment Systems HLV Heavy Lift Vehicle ACS Auxiliary Control System HTPB Hydroxyl-Terminated Polybutadiene Adv/Advcd Advanced HX Heat Exchanger AIAA American Institute of Aeronautics and Hyp Hypersonic Astronautics IAP Integrated Actuator Package Alt. Alternative IEC Inertial Electrostatic Confinement AMPM Agency Mission Planning Manifest IEF Inertial Electrodynamic Fusion ADN Ammonium Dinitramide IHPRPT Integrated High Payoff Rocket AP Ammonium Perchlorate Propulsion Technology APIO Advanced Planning and Integration Office IPT Integrated Product Team ARC Ames Research Center Isp Specific Impulse ARMD Aeronautics Research Mission Directorate ISS International Space Station ATP Authority to Proceed IVHM Integrated Vehicle Health Management CAD Computer Aided Design JSC Johnson Space Center CC Closed Cycle k Thousand CCDev Commercial Crew Development kg Kilogram CFD Computational Fluid Dynamics klbf Thousands of pounds of force

CH4 Methane KSC Kennedy Space Center CoPV Composite Overwrap Pressure Vessel LAS Launch Abort System COTS Commercial Orbital Transportation lbf Pounds of force Services LCC Life Cycle Cost CRAI Capability, Requirements, Analysis, and LENR Low-Energy Nuclear Reactions Integration LEO Low-Earth Orbit Cyc Cycle LH2 Liquid Hydrogen DCR Design Certification Review LOX Liquid Oxygen Demo Demonstration LPSTA Launch Propulsion Systems DGLR Deutschen Geselleschaft für Luft- und Technology Area Raumfahrt (German Scientific Society LST Life Support Technologies for Aeronautics) Lt. Wt. Light Weight DRA Design Reference Architecture Mgmt Management DLR Deutschen Zentrums für Luft- und Raumfahrt (German Aerospace Center) MHD Magnetohydrodynamics DRM Design Reference Mission Mlbf Millions of pounds of force Dyn Dynamic MPS Main Propulsion System ECLS Environmental Control and Life Support MSFC Marshall Spaceflight Center N Nitrogen EELV Evolved Expendable Launch Vehicle 2 Eff Efficient N/A Not Applicable EHA Electrohydrostatic Actuator NAI National Aerospace Initiative EHS Environmental Health System NEO Near Earth Object ELV Expendable Launch Vehicle NGLT Next Generation Launch Technology EMA Electromechanical Actuator NIA (Boeing) National Institute of Aerospace Eng Engine NRC National Research Council ESMD Exploration Systems Mission Directorate NTR Nuclear Thermal Rocket ETO Earth to Orbit OC Open Cycle Flt Flight OCT Office of the Chief Technologist FOM Figure of Merit OMB Office of Management and Budget GG Gas Generator Op Operational GOX Gaseous Oxygen Opt Option Grnd Ground ORSC Oxygen Rich Staged Combustion GW Gigawatt PBAN Polybutadiene Acrylonitrile HAN Hydroxyl Ammonium Nitrate Prop Propellant HC Hydrocarbon Proto Prototype HEDM High-Energy Density Material Pt. Point HEFT Human Exploration Framework Team Rad Radiation

DRAFT TA01-25 RBCC Rocket Based Combined Cycle RBS Reusable Booster System RCS Reaction Control System R&D Research and Development RLV Reusable Launch Vehicle RP Rocket Propellant (hydrocarbon-based) RSRM Reusable Solid Rocket Motor sec. Seconds SHLV Super Heavy Lift Vehicle SLI Space Launch Initiative SMD Science Mission Directorate SOMD Space Operations Mission Directorate SRB Solid Rocket Booster SRM Solid Rocket Motor SSME Space Shuttle Main Engine S/W Software Sys System T Metric ton TA Technology Area TABS Technology Area Breakdown Schedule TBCC Turbine Based Combined Cycle TDRS Tracking and Data Relay Satellite Tech Dev Technology Development Therm Thermal TRL Technology Readiness Level TVC Thrust Vector Control T/W Thrust to Weight (ratio) U.S. United States U/S Upper Stage

Acknowledgements The NASA technology area draft roadmaps were developed with the support and guidance from the Office of the Chief Technologist. In addition to the primary authors, major contributors for the TA01 roadmap included the OCT TA01 Road- mapping POC, James Reuther; the reviewers pro- vided by the NASA Center Chief Technologists and NASA Mission Directorate representatives, and the following individuals: Bart Leahy, George Story and Jonathan Jones.

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DRAFT TA01-27 November 2010

National Aeronautics and Space Administration

NASA Headquarters Washington, DC 20546 www.nasa.gov TA01-28 DRAFT