DRAFT Communication and Navigation Systems Roadmap Technology Area 05

Home , Apollo Docking Mechanism, Space Network

National Aeronautics and Space Administration

John Rush, Chair David Israel Calvin Ramos Les Deutsch Neil Dennehy Marc Seibert

November • 2010 DRAFT This page is intentionally left blank

DRAFT Table of Contents Foreword Executive Summary TA05-1 1. General Overview TA05-5 1.1. Technical Area TA05-5 1.2. Benefits TA05-5 1.3. Applicability/Traceability to NASA Strategic Goals, AMPM, DRMs, DRAs TA05-6 1.3.1. National Space Policy TA05-6 1.3.2. Agency Mission Planning Manifest (AMPM) TA05-6 1.3.3. NASA Communications and Navigation Infrastructure Requirements TA05-6 1.4. Top Technical Challenges TA05-7 1.4.1. Avoid communication from becoming a constraint in planning and executing NASA space missions TA05-7 1.4.2. Avoid navigation from becoming a constraint in planning and executing NASA space missions TA05-7 1.4.3. Minimize the impacts of latency in planning and executing NASA space missions TA05-7 1.4.4. Minimize user mass, power, and volume burden while improving performance TA05-7 1.4.5. Provide integrity and assurance of information delivery across the solar system TA05-7 1.4.6. Lower lifecycle cost of communications and navigation services TA05-8 1.4.7. Advancement of Communication and Navigation Technologies Beyond TRL-6 TA05-8 2. Detailed Portfolio Discussion TA05-8 2.1. Summary description and Technology Area Breakdown Structure (TABS) TA05-8 2.1.1. Optical Communications and Navigation Technology TA05-9 2.1.2. Radio Frequency Communications TA05-12 2.1.3. Internetworking TA05-13 2.1.4. Position, Navigation, and Timing TA05-15 2.1.5. Integrated Technologies TA05-19 2.1.6. Revolutionary Concepts TA05-20 3. Interdependency with Other Technology Areas TA05-21 4. Possible Benefits to Other National Needs TA05-21 Acronyms TA05-23 Acknowledgements TA05-23

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 05 input: Communication and Navigation 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 performs with acceptable risk—but a lack The Communication and Navigation Technol- of demonstration opportunities hinders this ogy Area supports all NASA space missions with process. the development of new capabilities and services In order to address these challenges a commu- that make our missions possible. Communication nication and navigation technology area roadmap links are the lifelines to our spacecraft that provide has been developed that includes identification the command, telemetry, and science data transfers of focus areas. One of the focus areas continues as well as navigation support. Planned missions to develop RF technology while initiating a par- will require a slight improvement in communica- allel path to develop optical communications cation data rates as well as moderate improvements pability. As RF technology development concen- in navigation precision. How-ever, advancement trates on getting more productivity out of the in communication and navigation technology will constrained spectrum bands that are allocated to allow future missions to implement new and more space users, optical communication seeks to take capable science instruments, greatly enhance hu- advantage of the virtually unconstrained band- man missions beyond Earth orbit, and enable en- width available in the optical spectrum. In addi- tirely new mission concepts. This will lead to more tion, the roadmap includes the migration of the productivity in our science and exploration mis- Earth’s internetworking technology and process- sions as well as provide high bandwidth commu- es throughout the solar system. The expansion of nications links that will enable the public to be a internetworking will help lower operational costs part of our programs of exploration and discovery. of our systems by replacing manual scripting and Today our communication and navigation ca- commanding of individual spacecraft communica- pabilities, using Radio Frequency technology, can tion links with autonomous handling of data dis- support our spacecraft to the fringes of the so- tribution similar to that of the terrestrial internet. lar system and beyond. Data rate range from 300 The position, navigation and timing focus area ad- Mbps in LEO to about 6 Mbps at Mars. As we dresses the key technology efforts necessary to im- move into the future there are a set of challenges prove navigation through investments in timing that will face the communication and navigation accuracy and distribution as well as make autono- technology area: mous navigation available for precise maneuvers, • As capabilities of our science instruments such as rendezvous and docking, anywhere in the advance, new mission concepts are developed, solar system. Realizing that there may be advan- and human exploration intensifies, we must tages to integrating technology developed across assure that our communication and navigation the communication and navigation area, a focus systems don’t become a constraint in planning area is identified in the roadmap that concentrates and executing our missions on this integration. This focus area also includes the integration of communication and navigation • As our missions move farther from Earth our technology developed in other technology areas communication and navigation technology such as in computing technology and advanced must minimize the impacts of latency in sensors. Since there may be game changing tech- planning and executing NASA space missions nology that could completely change the way we • While we advance the capabilities of our communication and navigate in the future “revo- communication and navigation systems and lutionary technology” is identified for possible de- improve their performance we must assure that velopment investments. Much of this focus area we minimize user mass, power, and volume is currently at a low TRL concept development burden on our missions stage. • In the future we envision serving a wider and The technology area strategic roadmap (TASR) more interactive public which could in-crease describes the communications and navigation security vulnerabilities and therefore must technology developments that are necessary to assure that we provide integrity and assurance meet the needs of future missions, provide en- of information delivery across the solar system hanced capabilities or enable new mission con- • Communication and navigation services must cepts. Representative future missions are shown be realized with reduced lifecycle cost at the top. Below this are key capabilities/invest- • In order to validate and infuse new ments that NASA will need to undertake to enable communication and navigation technology or enhance these missions. In some cases technol- we must demonstrate to missions that it ogy can be directly infused into missions after it DRAFT TA05-1 has been demonstrated in the laboratory. In other ly applicable to planned missions Low Density cases, where there is a major technology upgrade Parity Coding (LDPC) and a 15 w Ka-band Sol- and significant risk to the missions, a successful id State Power Amplifier (SSPA) would improve flight demonstration must be conducted and any mission performance as would the development new infrastructure required must be in place prior of Software Defined Radio (SDR) technology for to mission use. These two cases are depicted in the the next LEO standard S-band transceiver and the roadmap by triangle milestones for direct infusion Universal Space Transceiver (UST) operating in into missions and by squares for milestones that Ka-band. require flight demonstrations and/or major infra- However, major communication and naviga- structure investments prior to mission use. For ex- tion capability advancements would result from ample, surface wireless needs to be at TRL 6 by in-vestments in the technology focus areas in the 2019 in order to enable development of an auton- roadmap, thus enabling new classes of missions; omous networking capability in the 2027 time- several highlights are included below. frame, while hybrid optical com and navigation • Optical Communication: Development of sensing will require flight demonstration in 2021 photon counting detector technology focuses in order to allow pinpoint landing capability and on new materials and attempts to raise the enable missions not possible today. In this case the operating temperature for use in spacecraft. demonstration is necessary because of the level of Laser power efficiency improvements will help risk to the mission involved in introducing this pave the way for higher power lasers needed for radically new navigation technology. As can be communication from deep space. Addressing seen in the TASR, technology development must spacecraft induced jitter will improve laser begin long before its benefits can be realized by beam pointing capability. Initially optical the missions. The rows below the key capabilities/ terminals on spacecraft will use Earth-based investments in the TASR identify the main tech- beacons but eventual beacon-less pointing will nology focus areas that form the basis of the Tech- be developed. nical Area Breakdown Structure (TABS) • RF Communications: RF communication will In the TASR, pull technologies, those that en- develop new techniques that will allow at least able missions currently within the Agency’s plans, two orders of magnitude increase over current are connected directly to the missions that require data rate capabilities in deep space. Cognitive them, e.g. the CLARREO-1 mission will fly a 15 radios will be developed that will sense their W Ka-band SSPA. Later missions that are not environment, autonomously determine when completely defined as of yet require push tech- there is a problem, attempt to fix it, and learn nologies to enable their objectives. Push technol- as they operate. Communication through ogies enable new capabilities that enable missions harsh environments such as rocket plumes not currently possible. In addition, all missions and re-entry ionization will be addressed with require some form of both communications and technology such as Ultra Wide Band (UWB) navigation, it is expected that all missions that fly radios. after the development of a key investment/capa- Internetworking: bility will take advantage of it in their definition. • Earth-based internetworking Hence “Humans to NEO” would likely use the technologies will be migrated to space “100x Deep Space Downlink”, “Pinpoint Land- with protocols such as Disruptive Tolerant ing”, and “Low SWAP Deep Space Communi- Networking (DTN) which will help deal with cations”. Therefore, these technologies are linked latency issues and automate distribution of to the key capabilities. Many capabilities will re- data where ever our spacecraft operate. quire technology maturity from multiple technol- • Position, Navigation, and Timing: ogy development initiatives. The technology mile- Fundamental to the improvement of our stones represent achieving TRL 6. Adequate time navigation capability is the improved accuracy for each is provided in the TASR for their infu- and stability of our space clocks so significant sion into the operational communication and op- focus will be on this area. Algorithms for erations infrastructure. autonomous rendezvous, docking, landing, As is indicated in the roadmap, there are several and formation flying will be developed. communication and navigation technology devel- • Integrated Technologies: Development of opment efforts that will directly benefit current- hybrid optical and RF communication systems ly planned missions. Of the developments direct- should reduce mass and power requirements on

TA05-2 DRAFT National Aeronautics and Space Administration

Figure R: Communication and Navigation Systems Technology Area Strategic Roadmap (TASR)

DRAFT TA05–3/4 This page is intentionally left blank spacecraft. Integrating knowledge engineering our space communication capability, we must with future networking radios could provide make continuing investments in new technolo- cognitive networking functionality which gy. There is still enormous potential in further de- would further reduce dependence on manual velopment of RF technology that will help pro- control from Earth. Techniques will be vide the higher data rates that will be needed in developed to improve the use of the RF link as the future in order to not constrain new mission a science instrument (measuring perturbations capabilities. But there is also enormous potential along its path or in the spacecraft trajectory) in developing optical communication to a level of and enable these kinds of measurements using availability that matches that of RF communica- optical links. tion and unbridles the unrestricted optical band- • Revolutionary Technologies: Advancement of width for order of magnitude advances over pre- X-ray navigation using X-ray emitting pulsars sent RF capabilities. Position, Navigation and could provide the ability to autonomously Timing technology advancement will lead to the determine position anywhere in the solar ability for spacecraft to navigate autonomously system just as GPS does for Earth inhabitants. anywhere in the solar system. The vision of ex- Successful development of Supercon- tending the internet to space will require invest- ducting Quantum Interference Filter (SQIF) ments in not only development of new protocols technology would change the paradigm for and network topologies but also new ways of pro- RF communication to detecting the magnetic viding a secure environment for the vital commu- field instead of the electric field and pro- nications links that will be needed in the future. vide magnitudes of improvement in our And the transformation to the future could leap communication systems. ahead if investments in revolutionary concepts Many of the technology developments captured result in new “game changing” capabilities. The in this roadmap are of interest to other US Gov- communication and navigation roadmap that fol- ernment agencies and provide opportunities for lows provides the blue print for achieving this vi- collaboration. In addition, the development of sion. The roadmap is aligned with NASA missions these technologies will directly benefit commer- as projected at this time and, if followed, will meet cial sectors such as the telecommunication indus- emerging mission capability needs as well as pro- try and help promote the competitiveness of the vide new opportunities to expand mission capa- US industrial base. bilities in the future. 1.2. Benefits 1. General Overview Communications and navigation are enabling 1.1. Technical Area services that are required by all spacecraft. Invest- NASA’s space communication infrastructure ments in communication and navigation tech- provides the critical life line for all space missions. nology will ensure that future NASA missions are It is the means of transferring commands, space- not constrained by a lack of communication or craft telemetry, mission data, voice for human ex- navigation capability. It will allow our missions ploration missions, maintaining accurate timing to take advantage of more capable science instru- and providing navigation support. As mission ca- ments that will evolve in the future. For example, pabilities grow, the capability of the space com- on MRO, data collection for climate observations munication infrastructure must grow faster to avoid constraints on missions and to enable missions never before imagined. The vision of the future will transform the present NASA space communication and navigation capability from one of being a connection provider to being a flexi- ble service provider as we extend internet-worked technologies and techniques throughout the solar system and beyond. This vision includes enabling spacecraft to autonomously navigate and communicate back to Earth over self forming networks that are tolerant of disruptions. Figure 1. Mars Reconnaissance Orbiter (MRO) In order to bring about this transformation of Example DRAFT TA05-5 must be turned off while not over the poles because lic and educational institutions. Improvements in we cannot get the data back. At MRO’s maximum communications will allow extension of the ex- data rate of 6 Mbps (the highest of any Mars mis- ploration experiences into the home and class- sion to date), it takes nearly 7.5 hours to empty rooms of the general public. Data can be dissem- its on-board recorder and 1.5 hours to transfer a inated to experimenters in near real-time to allow single HiRISE image to Earth. In contrast, it will for improved experiments and provide telescience be possible within the next few years, with appro- capability. Live audio and video delivery allow for priate technology development, to have either an direct public involvement into the engineering RF or an optical communications solution at 100 challenges and excitement of scientific discovery. Mbps such that the recorder onboard a spacecraft 1.3. Applicability/Traceability to NASA at Mars could be emptied in 26 minutes, and an Strategic Goals, AMPM, DRMs, DRAs image could be transferred to Earth in less than 5 minutes. And if the solution is optical communi- The immediate goal of the communication and cations, a few cm-level ranging can drastically im- navigation technology development effort is to prove the spacecraft positioning and thus quality address any deficiencies identified by established of science data. missions. A secondary, long term goal is to pro- Technology investments in PNT will benefit vide NASA with new communication and navi- both human spaceflight and robotic spaceflight. gation capabilities that the missions can then use More precise positioning will enable higher qual- to provide new mission capabilities including en- ity data return from science instruments such as hanced public engagement. These goals are de- hi-resolution cameras, and will enable mission op- rived from the following policies and require- erations such as precise landing and deep space ments discussed below. formation flying that are not possible with today’s 1.3.1. National Space Policy navigation capability. The newly released “National Space Policy” Sub-meter positioning will be needed for pre- states “Space operations should be conducted in cision formation flying missions and a pinpoint ways that emphasize openness and transparency to landing capability on the order of 100-meters will improve public awareness of the activities of gov- be required to land crews proximate to pre-posi- ernment, and enable others to share in the bene- tioned supplies. In addition, improvements in ar- fits provided by the use of space”. NASA’s com- eas such as the use of GNSS in Earth orbit will en- munications systems are critical to fulfilling this able autonomous navigation which ultimately will goal and this technology area will enable this by reduce the cost of mission operations and enable extending Internet-like connectivity everywhere mission capabilities (e.g., autonomous rendez- NASA explores. Furthermore, most of the “goals” vous, proximity operations and docking) beyond are directly enabled by a strong NASA commu- LEO. The benefits that would accrue to human nications and navigation capability. In addition, spaceflight would include reduced mission risk, these same systems will enable the sharing of lowered operations costs through significantly less emergency information as outlined in the Policy. ground-control intervention, and new capabilities 1.3.2. Agency Mission Planning Manifest for robotic pre-positioning of key assets and, sub- (AMPM) sequently, for crewed precision landings on planetary and/or NEO surfaces. Each specific mission in the AMPM and each Extending networking to space will decrease the likely mission concept to be proposed for future cost of missions through autonomous transfer of competitions is analyzed to understand the like- data where today such transfers involve high levels ly communications and navigation desires. These of manually scheduling and scripting. This will be are turned into trends in major figures of merit analogous to how the terrestrial internet autono- (FOMs). All technology investments in this area mously transfers information without human in- are tied to these trends or to their extrapolation— tervention. However, due to the disruptive nature the latter creating push technologies. of the space environment (long latency and inter- 1.3.3. NASA Communications and mittent connectivity), new protocols and network Navigation Infrastructure architectures will need to be developed. Requirements Development of communication technolo- These NASA requirements shape the Agency’s gy will also benefit the average American citizen current communication and navigation technol- through improved agency outreach to the pub- ogy investments and can serve a guide for future

TA05-6 DRAFT investments in this area. The current requirements 1.4.2. Avoid navigation from becoming a include: constraint in planning and executing a. Develop a unified space communications and NASA space missions navigation network infrastructure capable of NASA’s future missions show a diverse set of meeting both robotic and human exploration navigational challenges that we cannot current- mission needs ly support. Precision position knowledge, trajectory determination, cooperative flight, trajectory b. Implement a networked communication and traverse and rendezvous with small bodies are just navigation infrastructure across space some of the challenges that populate these con- c. Provide the highest data rates feasible for both cepts. In addition, our spacecraft will need to do robotic and human exploration missions these things farther from Earth and more auton- d. Assure data communication protocols for omously than ever before. Proper technology in- Space Exploration missions are internationally vestment can solve these challenges and even sug- interoperable gest new mission concepts. Since there is a requirement for international 1.4.3. Minimize the impacts of latency in interoperability, select technology development planning and executing NASA space tasks in the internetworking and RF technology missions areas will be conducted in coordination with the Many of the complex things future missions will international standards bodies such as the Consul- need to do are hampered by keeping Earth in the tative Committee for Space Data Standards (CC- real-time decision loop. Often, a direct link to the SDS). Earth may even not be available when such decisions are desired. This can be mitigated by mak- 1.4. Top Technical Challenges ing decisions closer to the platform – minimizing 1.4.1. Avoid communication from becoming reliance on Earth operations. To do this, the com- a constraint in planning and munications and navigation infrastructure must executing NASA space missions be advanced to allow information to be gathered A recent analysis of NASA’s likely future mission locally and computation to be per-formed either set indicates that communications performance in the spacecraft or shared with nearby nodes. will need to grow by about a factor of ten every Space Internetworking is an example of an en- ~15 years just to keep up with what we believe abling technology in this area. Clearly this goal will be robotic mission requirements. A second di- is coupled with the need for in-creased autonomy mension of the challenge is measured simply in and flight computing. Technology investment can bits per second. History has shown that NASA solve these challenges and even suggest new mis- missions tend to return more data with time ac- sion concepts. cording to an exponential “Moore’s Law”. 1.4.4. Minimize user mass, power, and Missions will continue to be constrained by the volume burden while improving legally internationally allocated spectral band- performance width. NASA’s S-band is already overcrowded and Future missions will demand increased commu- there are encroachments at other bands. nications and navigation performance. This performance must be delivered while reducing mass, power, and volume burden on the spacecraft. This can be measured by metrics such as Watts per data bit or kg per data bit. This will allow more resources for crew or science instruments. 1.4.5. Provide integrity and assurance of information delivery across the solar system Future missions will have increased international partnerships and increased public interaction. This will imply increased vulnerability to information compromise. As mentioned in the 2012 Sci- Figure 2. Downlink Rate Drivers as a Function of ence and Technology Priorities Memo from the Time DRAFT TA05-7 Table 1. Example Challenge Progress Goals Challenge Example Progress Goals Near-term (thru 2016) Midterm (2017-2022) Far-term (2023-2028) 1 Remove Comm. as a 200 Mbps from 1 AU 20 Gbps from 1 AU Constraint 30 Gbps from LEO 3 Tbps from LEO 2 Remove Nav. as a Increased reliance on next generation Increased reliance on in-situ obser- Fully autonomous PNT functions for Constraint international GNSS (GPS, GLONAS, Galileo) vations, data fusion, and autono- all missions throughout the solar receiver based navigation below GEO as well mous PNT; supervised autonomy for system; GPS-like navigation at Mars as a technology push for in-situ navigational missions beyond GEO observations, sensor data fusion, and autonomous PNT 3 Minimize Impact of Navigation/timekeeping to support Navigation/timekeeping to support: Navigation/timekeeping to support: Latency -Semi-Autonomous pinpoint landing with -Autonomous pinpoint landing with -Autonomous pinpoint landing with 100-m accuracy: 10-m ac-curacy 1-m accuracy - Millimeter-level formation control - Micrometer-level formation control - Nanometer-level formation control 4 Minimize user burden Reduction of 50% in transponder Reduction of 75% in transponder mass mass 5 Integrity & Assurance Interplanetary info security including inter- Standard international trust relation- Global information trust relation- national trust relation-ships with conditional ships established and managed ships security levels operationally Internationally-standard uncondi- Validate unconditional information security Unconditional information security tional information security with all techniques to low-Earth orbit (LEO) techniques employed with LEO and space missions some deep-space missions 6 Lower Lifecycle Cost 20% Reduction from current 40% Reduction from current 80% Reduction from current 7 Lack of Demo’s Optical comm. demo Multi-function SDR demo Deep space relay tech demo White House, we need to “Support cybersecuri- realize the benefits of the technology described in ty R&D to investigate novel means for designing this roadmap, flight demonstrations of new tech- and developing trustworthy cyberspace—a sys- nologies must be performed. tem of defensible subsystems that operate safely in an environment that is presumed to be compro- 2. Detailed Portfolio Discussion mised” As we extend Internetworking throughout the Solar System, we need to proceed in a safe and 2.1. Summary description and Technology secure manner. Area Breakdown Structure (TABS) The chart below shows the Technology Area 1.4.6. Lower lifecycle cost of Breakdown Structure (TABS) for Communica- communications and navigation tions and Navigation Systems. The technology services is divided into six major areas. The first five are Future missions will be ever more complex. The viewed as enabling evolutionary developments current NASA methods of providing communi- and the final one is revolutionary. cations and navigation services will not scale in a Optical Communications (5.1) deals with the cost-effective way. NASA should work to reduce various technologies required to make communi- the cost of providing these services, reducing bur- cation with light practical. den on its operators, even as the mission set ex- Radio Frequency Communications (5.2) strives pands and becomes more challenging or more cost to dramatically accelerate techniques in use to- constrained. day for NASA’s missions. Though quite a bit more 1.4.7. Advancement of Communication mature than optical communications, there is and Navigation Technologies still a great deal of promise for technology break- Beyond TRL-6 throughs in the RF domain. However, all RF tech- As part of the technology advancement process, nology development will be focused on RF spec- in order to advance beyond TRL-6, communica- trum that had been allocated for space use by the tion and navigation technologies must be demon- International Telecommunication Union (ITU) strated in the space environment. However, flight and where adequate bandwidth would pro-vide a projects are reluctant to assume the risk of car- useful service, or where the application is beyond rying demonstration hardware or software, since the near Earth environment. Many of the key they must also carry redundant operational sys- technical challenges could be met by either op- tems to ensure mission success. Without demon- tical or RF communications so NASA will invest strations, flight projects are unlikely to rely on new in both paths, with appropriate decision points. technology for operational systems. For NASA to Internetworking (5.3) deals with extending terrestrial Internet-like concepts throughout space. TA05-8 DRAFT Figure 3. Technology Area Breakdown Structure 2.1.1. Optical Communications and Position, Navigation, and Timing (5.4) provides Navigation Technology all the technologies required to know where our Current Status: spacecraft and their targets are, understand their Currently NASA is in the process of migrating trajectories, and synchronize all systems. Integrat- its high rate mission data to Ka-band as part of ed Technologies (5.5) deals with crosscutting tech- a continuing trend in the demand for high data nologies that work in combination with the oth- returns from our science missions. However, it is er areas to maximize the efficiency of our missions. expected that the trend toward higher data rate Revolutionary Concepts (5.6) are those technol- needs will continue in the future and will even- ogy ideas that are truly on the cutting edge. Items tually surpass the capacity available with Radio placed here are so “far out” that the development Frequency (RF) Ka-band. At that point in time approaches are not yet well understood. These are NASA plans to migrate from Ka-band to optical typically items that are simultaneously very high communication which provides access to unreg- risk but very high payoff if they materialize. As ulated spectrum and will support the data rates items here mature, they might be moved to other that will be needed by the next generation of sci- appropriate areas of the Roadmap. ence instruments. This migration will be especially valuable to our deep space missions, which will be able to realize higher data rates than with RF DRAFT TA05-9 Figure 6. LADEE Optical Communication System system on LRO. The system will also demonstrate Pulse Position Modulation (PPM) which will be a key factor in optical communications from deep space locations in the future. The optical termi- Figure 4. Ka-band vs. Optical Data Rates nal on LADEE will be suited for demonstrating communications with flight terminals that will the capability in Near Earth missions. The flight impose an equal, or lower, power and mass burden terminal’s optical module technology is applica- on spacecraft and have significantly less aperture ble for use in LEO and GEO applications. How- size than RF antennas. The first experimental op- ever, with the shorter distance coherent modula- tical terminals, developed by foreign space agen- tion should be developed and would replace the cies, are currently providing high-rate communi- PPM system to be used on LADEE. With coher- cations demonstrations (up to 6 Gbps crosslink) ent modulation, this system will be able to oper- in low Earth orbit. A common feature of these sys- ate at the multi-Gbps level at GEO and below. An tems is the use of Earth-based beacons for acqui- initial design for a Deep Space Optical Commu- sition and tracking. Longer term, reliance on bea- nications Terminal (DOT) is targeted for a poten- cons should be eliminated. It should also be noted tial Mars demonstration mission, transferring 250 that optical communication also has the side ben- Mbps from closest Mars approach. Both systems efit of cm-level ranging, an order of magnitude use supercooled nano-wire technology to provide better than RF. the best performing ground photon counting de- NASA has begun development of optical com- tectors. Both the LADEE and DOT optical communication technology with strategic investments munication systems will also be able to make very in key areas and has progressed to the point where significant improvements in spacecraft position this new capability will be demonstrated on the determination with ranging accuracies at the few LADEE spacecraft in 2013. The main goal of this cm-level. demonstration is to prove the fundamental con- Major Challenges: cepts and transfer up to 622 Mbps from Lunar Low received photon density is a major concern, distance, roughly six times the rate of the Ka-band especially for deep space applications where even a laser signal is subject to the classic inverse distance square loss. Extraneous “noise photons” such as might occur when pointing close to the Sun, drive the need to distinguish the transmitted photons. The narrow beam widths involved require precise acquisition and tracking as well as vibration mitigation. Increasing laser lifetime is critical for long-duration missions. At the same time increasing laser power efficiency from the current 10 – 15% to around 30% while decreasing mass and cost will be an important factor in moving optical communication capability forward, especially for deep space applications. Atmospheric conditions including clouds, clear air moisture content, and atmospheric turbulence can be a major challenge Figure 5. Deep Space Optical Terminal Concept to eventual operational acceptance of optical com-

TA05-10 DRAFT Table 2. Mapping of optical communications tasks into the Top Technical Challenges

1 Remove Comm. 2 Remove Nav. as 3 Minimize Impact 4 Minimize 5 Integrity & 6 Lower Life- as a Constraint a Constraint of Latency user burden Assurance cycle Cost Detector Development X X X X Large Apertures X Laser Improvements X X X X Acquisition and Tracking X X Atmospheric Mitigation X X X X munication. High-performing space-based optical that could be obtained at a reasonable cost will receiver systems will be required for space-based open opportunities in terms of higher uplink rates uplinks and relay applications, however, the best to spacecraft, or development of Earth-based re- performing detectors today require super-cooling. lays for downlinks from spacecraft operating in Overcoming the Challenges: deep space. As depicted in the TASR, the optical commu- Laser Improvements: Investments in improv- nications technology development effort begins ing space-based lasers should include improve- with developing the technologies to support near ments in amplifiers that enable higher power op- Earth optical communications. This technolo- erations and also focus on extending the lifetime gy progresses from near Earth capabilities to de- of the terminal. The near term effort should in- velopment of larger terminals to support deep clude improvements in pump diode lifetime and space optical communications. Later in the opti- increasing laser power to 5 W and above for high cal communication development process, beacon- data rate deep space applications as well as work less tracking will be developed that will enable op- to-ward more power efficient lasers. tical communications for the outer planets. Also, Acquisition and Tracking: A number of initia- in order to enhance deep space optical commu- tives are needed in order to improve acquisition nications, technology will be developed to enable and tracking of the optical signal. This includes: Earth-based satellites to relay deep space optical better vibration mitigation through either passive communications to Earth. In order to overcome or active means; improved stabilization systems the challenges listed above, some key initiatives such as introducing fiber optic gyro (FOG) tech- have been identified. Each may address multiple nology which could effectively extend beacon- challenges. aided acquisition beyond Mars; eventual devel- Detector Development: Work must continue opment of beaconless pointing capability which to improve photon-counting detectors. This in- would allow the use of optical communications cludes improving the yield in the assembly of su- technology throughout the solar system. per-cooled nano-wire detector arrays and exper- Atmospheric modeling and mitigation: This imenting with detector performance at higher includes experimenting with reception of signals temperatures. Raising the temperature will allow from spacecraft terminals in varying atmospheric quicker transition to space-based optical commu- conditions and development of methods for han- nication receivers such as optical communications dling the handover of the signal from space to al- relays and mission uplinks. In addition, alternate ternate ground stations in the event that clouds or technology should be investigated such as the Sil- other atmospheric conditions cause disruption of icon Nano-wire technology, which if successfully a link. In addition, development of adaptive op- developed would be able to operate at higher tem- tics and/or large detector arrays for mitigation of perature ranges and be more suitable for space- atmospheric turbulence effects on optical signals based use. For applications at GEO and below, co- is needed. In order to accelerate this work, mod- herent modulation/demodulation systems should els of optical communication signal performance be developed. This work should be closely coordi- in the Earth’s atmosphere will be developed and nated with work outside of NASA where there are validated through experimentation. Subsequent common technology development interests. model development will extend the modeling ca- Large apertures: Development of virtual large pability to atmospheres of other bodies in the so- apertures for ground reception that cope with the lar system. weak received signals will be needed for deep space Overlaps and Potential Synergies: applications. In addition, light weight space-based To this point all NASA investments in optical large aperture optics or space-based optical arrays communications have been coordinated through DRAFT TA05-11 mission communities need for more and more data return. In addition, we will need to make significant strides in increasing uplink and developing innovative approaches to conduct emergency communications to enable safe and efficient human exploration and autonomous robotic space operations. Since radio spectrum is controlled by international law, we are always chal- lenged to get as much use out of our allocated spectral bands as possible. RF links between Figure 7. Comparison of Various Coding Schemes spacecraft (e.g., crosslinks or support of in-situ ex- NASA’s SCaN office, which has made an effort ploration) will become more prevalent in future to avoid overlaps and leverage synergies. Howev- mission concepts. We will also need to increase er, there are potential synergies with other NASA the performance of in-situ surface wireless compro-grams in areas such as optical instruments and munication on bodies other than Earth. Commu- cryogenics that must be further investigated. nications through harsh environments provides a major challenge during critical phases of our mis- 2.1.2. Radio Frequency Communications sions. Finally, we must manage these new tech- Current Status: nologies together with the in-crease in number of Radio Frequency (RF) Communications is used spacecraft and ever more complex mission oper- on all of NASA’s current space missions. ations without huge in-creases in operations or Near-Earth missions drive the current state-of- maintenance costs. Since this technology area is the-art for data rates, data volume, and bandwidth more mature than optical communications, devel- efficiency. With today’s technology, downlink data opments should also focus on more efficient use rates can be more than 1 Gbps. The highest avail- of power, available spectrum, mass, and volume. able NASA data rate, however, is 300 Mbps from Overcoming the Challenges: TDRSS. As depicted in the TASR, early RF communica- Since communication performance is inversely tions development will focus on development of a proportional to the distance squared, deep space reprogrammable software defined radio that can missions tend to push the art in other directions – then be used as an infusion path for subsequent particularly in power efficiency. Mars Reconnais- developments. The mid-term focus is on reduc- sance Orbiter (MRO), which can return 6 mbps ing SWAP for major components. The following when Mars and Earth are at their closest distance, paragraphs describe the technical solutions that is the state of the art in deep space communica- will be executed to address the challenges. tions. Spectral-efficient technology: Spectral band- Currently, there are critical phases of our mis- width is a precious and legally enforced com- sions where standard RF techniques do not work. modity. We need to get as much use as we can These include communication through launch from what we have been allocated. This means us- plumes and communications through plasma during ever more clever ways of fitting more bits into ing Earth reentry. We need to mitigate these prob- the same number of Hertz. It also means being lems to ensure mission safety and success. ever-vigilant to reduce radio frequency interfer- Major Challenges: ence and stay robust to interference from others. The major challenge is to keep in front of the High order modulation schemes (e.g. 8PSK and Table 3. Mapping of RF communications tasks into the Top Technical Challenges

1 Remove Comm. 2 Remove Nav. 3 Minimize Im- 4 Minimize 5 Integrity & 6 Lower Life- as a Constraint as a Constraint pact of Latency user burden Assurance cycle Cost Spectral-Efficient Technology X X Power-Efficient Technology X X Propagation X X X Flight and Ground Transceivers X X X Earth Launch and Reentry Com- X X munications Antennas X X X

TA05-12 DRAFT 16 QAM) as well as careful pulse shaping (e.g., technology in two main areas. The NASA Space GMSK) are examples of current technology in- Communications and Navigation (SCaN) Office vestments in this area. in SOMD maintains a technology program that Power-efficient technology: Spacecraft pow- provides the main Agency investment. In addi- er is a precious commodity for many missions tion, mission directorates (most notably the Mars and the communication system is a tradition- Program within SMD) typically invest in mission- al major user of this power. We must continual- specific systems. There are likely other synergies ly strive to reduce the amount of power required that must be investigated with NASA programs to return each bit from space. Efficient power am- that invest in science instruments such as radars. plifiers and error correcting codes are two of the NASA is also investigating synergies between RF standard technique for advancing power efficien- and optical communications including the use of cy. Another is the use of higher carrier frequencies common system elements. such as moving from X-band (~8 GHz) to Ka- 2.1.3. Internetworking band (~32GHz) in deep space. Further gains are possible through the use of advanced data com- Current Status: pression, coding, and modulation techniques – To date, most space communication scenarios and through careful combinations and creative in- have involved fundamental point-to-point links tegration of these with data sampling. between a spacecraft and Earth. Today’s special- Propagation: The more we understand about ized link-layer protocols and carefully planned how our signals move through space and atmo- and scheduled link operations have thus far been spheres in the allocated frequency bands, the more adequate to meet the needs of missions. Current- innovative we can be in developing better-per- ly, there is a rudimentary internetworking capa- forming transmission and detection algorithms. bility between ISS and the ground using standard This knowledge, including atmospheric model- Internet protocols. There have also been a number ing and simulation, is needed for development of of technology demonstrations of space-based in- future concepts for arraying both spacecraft and ternetworking technologies, including the CAN- ground antennas, and critical for developing ro- DOS Project (Communications and Navigation bust reentry communications. Demonstration on Shuttle) that demonstrated Flight and Ground Transceivers: Develop the mobile IP, the CLEO Project that placed a Cisco technology to enable the future radio systems router in low Earth orbit, and Deep Impact Net- (flight and ground) including miniaturized com- working Experiment (DI-NET) that placed DTN ponents, cognitive systems (self configuring and protocols in deep space. environmentally aware), weak signal operations, Major Challenges: and lower operations and maintenance costs. Availability: The terrestrial Internet assumes Earth launch and reentry communications: that there is always a real-time and reliable path Characterize the harsh environment and develop between the source and destination. In space, our solutions such as use of ultra wide band (UWB), nodes are often not available for communications, space-borne terminals, adaptive, or cognitive sys- either because the spacecraft is not in view or be- tems. cause it is busy doing other tasks. Messages must Antennas: Both flight and ground antennas are be able to pass through this network even when considered in this element. As we move to high- intermediate nodes appear and disappear. er carrier frequencies, we need to ensure we can Latency: Space links, because of the long dis- develop antennas that are efficient and can be tances involved, are not conducive to standard pointed. We also need to consider arrays of an- Internet solutions. In addition, the long latency tennas as an option to building ever-larger sin- makes many real-time adaptive techniques impos- gle dishes. For flight systems, we need to inves- sible. tigate various forms of deployable structures, as Autonomous operations: As missions become well as techniques for adaptively combing aper- more complex and further from Earth resources, tures. Combining of antennas for receiving signals there will be a need to support more autonomous is already advanced. However, focused technology operations with minimal Earth contact. With in- development should be directed towards antenna creasing levels of autonomy, entirely new class- combining in the transmit direction. es of missions are also being envisioned where as- Overlaps and Potential Synergies: sets would routinely coordinate among themselves NASA currently invests in RF communication without ground intervention to achieve mission DRAFT TA05-13 Table 4. Mapping of internetworking communications tasks into the Top Technical Challenges 1 Remove Comm. 2 Remove Nav. 3 Minimize Impact 4 Minimize user 5 Integrity & 6 Lower Life- as a Constraint as a Constraint of Latency burden Assurance cycle Cost Delay-Tolerant Networking X X X X X Adaptive Network Topology X X X X X Security X Integrated Network Management X X X X objectives. There will be a need for remote com- Disruption-Tolerant Networking (DTN): In- munications networks to enable communication ternetworking protocols (e.g., surface wireless between platforms, as well as a need to config- and proximity, quality of service, network man- ure and maintain dynamic routes, manage the in- agement and information assurance, adhoc net- termediate nodes, and provide quality of service working, etc.) are critical to enable automation functionality. of connections and data flows and disconnection Information Assurance: NASA information is (store-and-forward) multi-hop friendly applica- vulnerable to many factors including hardware, tions. In fact, the Agency has recently invested software, and human intervention. As NASA’s sci- in DTN to provide a set of basic services in the ence and information sources become inter-leaved FY2015 timeframe to allow coordination among with terrestrial public domain networks to sup- platforms. Advances in space-based, high speed port initiatives such as STEM and interna-tion- routing technologies will also be necessary to en- al collaboration, it will be imperative to protect able internetworking across future high band- NASA’s assets and operations, and facilitate seam- width links (proximity and end to end). less authentication of users and assuring that all Adaptive Network Topology: Develop robust messages are transferred without compromise. ad hoc and mesh networking of mobile elements Complex Network Topologies: Earth Science, to coordinate timing, position, and spacing within Astrophysics, Human Origins, and Solar-Terres- the operational needs of human and robotic mis- trial missions will require multiple communica- sions. Consider advanced methods of channel ac- tions and networking topologies to meet future cess including multiple and demand access. Main- missions, to include multiple spacecraft flying in tain quality of service across the dynamic network. formation e.g. to create unprecedented telescope Traffic modeling and simulation will be critical apertures and interferometers for imaging faint- tools to define and validate topologies. er, smaller, and more distance objects. Commer- Information Assurance: Develop information cial in-space servicing and orbital debris removal, assurance architecture technologies to a) ensure heavy lift vehicle stacking, and assembly of sepa- system safety, data integrity, availability and, when rately launched telescope mirrors require precise required, confidentiality and b) to enable use of all navigation and proximity communications. Com- available links and networks – some which may be plex and time-varying networks of spacecraft and provided by other agencies or countries. Space in- sensors must be capable of sharing rich, near-real- formation assurance protocols will also enable sys- time streams of information. tem self-awareness of actual versus expected pat- Minimizing Spacecraft Burden: Minimize the terns of operation to detect anomalies that may implementation footprint of the internetworking indicate information assurance breaches, system software, memory, and processing for spacecraft failures, or safety hazards and have the ability to nodes is essential for space implementation. automatically execute plans to reroute critical traf- Overcoming the Challenges: fic in the event that critical systems are compro- As depicted in the TASR, the early focus will mised or destroyed. capitalize on investments made by NASA in Integrated Network Management: Devel- DTN technology development that will enable op integrated network management architectures future networking capabilities throughout the and protocols to effectively support autonomous solar system. This is followed by expanding the operations with adaptive network monitoring, functionality to include a broader spectrum of con-figuration and control mechanisms including communication and navigation services exploit- integrated health management (IHM). ing autonomous and cognitive technologies. The Overlaps and Potential Synergies: technical solutions that will address the challenges As the need for autonomous operations and re- are described below. duced reliance on Earth based resources evolves,

TA05-14 DRAFT internetworking protocols and technologies will Navigation relies on precision time and frequen- be needed to support challenging missions within cy distribution and synchronization. The near- SMD and ESMD and for complex topologies sup- Earth GPS-based time/frequency reference and porting future aviation applications in ARMD/ time transfer capabilities are in the nanosecond FAA (e.g. high density terminal operations). Ad- range and the micro-second range, respectively. ditionally, NASA will seek to leverage advances in The use of quartz resonators for on-board time/ commercial and other government agency's com- frequency generation is most common. The GPS munications and networking technology develop- satellites employ rubidium and/or cesium atom- ment, to include network mobility, ad hoc netic clocks for ultra-stable timekeeping. The short- working, and security. term and medium-term stability performance of 2.1.4. Position, Navigation, and Timing the current generation of space clocks, in terms of Allan Variance, currently spans the 10-13 to Current Status: 10-14 range for intervals of 1-10 seconds and is with- NASA’s current PNT state-of-the-art relies on in the 10-13 to 10-15 range for longer intervals of both ground-based and space-based radiomet- 100 seconds. Current long-term space clock per- ric tracking, laser ranging, and optical navigation formance ranges from 10-12 to 10-13 over time in- techniques (e.g. star trackers, target imaging). A tervals greater than 1000 seconds. variety of radiometric ranging techniques are used All the above PNT methods are technically and throughout the NASA communications networks. operationally mature and have thus far been ade- Post-processed GPS position determination per- quate for NASA’s mission needs. formance is at the cm-level at Near-Earth distanc- Major Challenges: es and meter-level at High Earth Orbit distanc- Future missions will require precision landing, es. Autonomous real-time GPS performance, such rendezvous, formation flying, cooperative robot- as that produced by the Goddard Enhanced On- ics, proximity operations (e.g., servicing), and co- board Navigation System (GEONS) can achieve ordinated platform operations. This drives the accuracies of at least 20 meters. need for increased precision in absolute and rela- Position determination performance is better tive navigation solutions. than 10m at near-Earth distances, and is 10s of As we operate further from Earth and perform km at the distance of Mars. The Deep Space Net- more complex navigational maneuvers, it will be work (DSN) employs a high-accuracy Very Long necessary to reduce our reliance on Earth-based Base Line (VLBI) method that yields position de- systems for real-time decisions. This will require termination performance of 1km at Mars, a few reduced dependence on ground-based tracking, kilometers at Jupiter, and 100s of km at distances ranging, and trajectory/orbit determination sup- beyond Jupiter. Optical navigation methods yield port functions (to minimize latency and availabil- position determination performance of 1 km at ity constraints). Since timing is a fundamental near-Earth distance and 10s of km at Mars dis- parameter for adequate navigation, we will need tance. increased precision in reference time/frequency generation, time/frequency distribution, and synchronization. Space-qualified clocks are not available today with the desired precision for future missions. Reducing reliance on Earth systems also requires clocks that are orders of magnitude more precise that the best space-qualified clocks today. Also, the use of multi-hop communications presents a challenge for PNT support in terms of measurement of radiometric tracking data (RMTD). The transit delays through each node and the ephemeris knowledge of each node contribute to RMTD measurement errors, hence PNT errors on the final node. Increased precision in each individual node’s PNT system will be required in order to minimize the error contributions of each hop to the final node’s PNT solutions. Figure 8. PNT Development Timeline The platforms which are “first down” on a NEO DRAFT TA05-15 or a planetary surface may have limited ground sought could be based upon highly stable quartz inputs and no surface/orbiting navigational aids. crystal resonators or on techniques which mea- NASA currently does not have the navigational sure atomic transitions to establish the frequen- and trajectory/attitude flight control technologies cy standard for the timing system—including op- that permit the fully autonomous capabilities for tical clocks. Major technical challenges for space approach and landing. clocks using quartz resonators include reducing Overcoming the Challenges: their sensitivity to the on-board thermal environ- As depicted in the TASR, the early focus is on ment conditions and their susceptibility to mag- increasing PNT accuracy and precision, with netic and electric field, g-force, and ionizing ra- the later focus on autonomy. An overall goal of diation effects. The primary technical challenges these technology investments is to position NASA for atomic-based space clocks are to reduce their to conduct human space flight missions beyond complexity and cost while maintaining their high- LEO. The following paragraphs describe the tech- end performance. Common technical challenges nical solutions that will be executed to address the include reducing the overall timekeeping system challenges. SWAP resource requirements, radiation hardened As notionally depicted in figure 8 above, we en- low- noise clock readout electronics, and lastly the vision a phased PNT technology development software algorithms which process the clock mea- effort over the next 15-20 years that starts with surements and estimate/propagate the timekeep- foundational work in timekeeping and time/fre- ing model which generates the time/frequency quency distribution/time synchronization cou- signal output(s). Advanced time-keeping systems pled with developments in navigational sensors will require technology developments to address and filters. Research into the next generation of the aforementioned technical challenges. Research multi-purpose navigation filtering techniques is also needed into new timekeeping system archi- is needed (e.g. adaptive filtering) to improve on tectures in which outputs of an ensemble of clocks the current ad-hoc mission-unique Kalman Fil- are weighed and software filtered to synthesize an ter based approaches used since Apollo. The de- optimized time estimate. velopment of component-level PNT technolo- Time/Frequency Distribution: NASA mis- gy building blocks will permit the synthesis and sion applications, both for navigational functions implementation of early semi-autonomous (e.g. and in the fundamental science realm, will ben- supervised autonomy) PNT flight systems. Sub- efit from having a robust and reliable common sequently, based upon the flight results of the time/frequency reference that can be shared pre- semi-autonomous missions together with invest- cisely across the Solar System. The ability to per- ments in autonomous systems technology, NASA form precise time/frequency transfer is coupled will be in an excellent position to fly missions hav- with the anticipated technology developments for ing fully autonomous PNT functions. Attaining space clocks. As the frequency stability of space this goal will have benefits for human and robot- clocks improves the need for precise time/frequen- ic spaceflight in all flight regimes: near-LEO, be- cy transfer will increasingly emerge as the driv- yond-LEO, and deep space. There will be inter- ing ‘timing’ problem. Technology investments action between the technology areas identified in are needed to provide the service function of col- figure 8 as NASA works towards the goal of hav- lecting, formatting to a common interface stan- ing fully autonomous PNT functions available dard, and communicating PNT data across a het- where needed. The convergence of the technology erogeneous network of space and ground based areas indicated in the figure will culminate in first- platform nodes. Research and development is re- of-a-kind NASA capabilities for AR&D and PFF quired at three levels: systems re-search (e.g., time/ missions, which absolutely require the highest lev- frequency distribution architectures/techniques/ el of autonomy and PNT performance. methodologies, system error/uncertainty model- Timekeeping: The development of a new inte- ing), hardware component development (e.g., RF grated space-qualified timekeeping system with or optical communications devices to affect time/ ultra high accuracy and frequency stability per- frequency transfers), and software component de- formance is to be considered not only for PNT velopments (e.g., filtering algorithms to propagate functions but also for fundamental physics, time real-time estimates of the common time/frequen- and frequency metrology, geodesy and gravime- cy reference). Nanosecond-level time transfer ca- try, and ultra-high resolution, VLBI science ap- pability across the Solar System is envisioned as plications. The advanced timekeeping systems a long-term goal given that this level of time/fre- TA05-16 DRAFT quency transfer is the state of the art on Earth. We will also need to develop methods for accurate time/frequency distribution in the space Internet- working environment—especially when there is not a direct real-time path back to Earth. On-Board Autonomous Navigation and Ma- neuvering Systems: The principle mission -driv ers for autonomy are: servicing/assembly, sample return, formation flying, and pinpoint landing. In-vestments in technologies to implement autonomous on-board navigation (and maneuvering) will permit a reduction in dependence on ground-based tracking, ranging, trajectory/orbit/ attitude de-termination and maneuver planning Figure 9. Formation Flying Mission Concept support functions. Autonomous navigation and and infrared cameras), radar sensors, radiometrics, maneuvering technologies will be needed for all fine guidance sensors, laser rangefinders, high vol- classes of space platforms: from robotic spacecraft ume/high speed FPGA-based electronics for LI- and planetary landers to crewed exploration vehi- DAR and other imaging sensor data processing, cles to planetary surface rovers. In the near-term sensor measurement processing algorithms, syn- gradually increasing levels of autonomous naviga- thetic vision hardware/software, and situational tion capabilities will allow platforms to go longer awareness displays. between time and state vector updates from the Relative and Proximity Navigation: The ca- Earth. A significant benefit to be attained in this pability to perform multi-platform relative nav- case will be a reduction in the burden of routine igation (i.e., determine relative position, relative navigational support. Less reliance on the ground- velocity and relative attitude/pose) directly sup- based navigational support will reduce commu- ports cooperative and collaborative space plat- nication requirements on network services mak- form operations. There is a cross-cutting mission ing them available for missions with less on-board ‘pull’, from both the envisioned human explora- autonomy. An additional benefit that will accrue tion missions as well as the robotic science mis- from having autonomous on-board navigation sions, for relative navigation technologies. One and maneuvering capabilities will be an increase well-recognized such cooperative operation that in platform’s operational agility, enabling near re- relative navigation enables is Automated Rendez- al-time re-planning and opportunistic science. In vous and Docking (AR&D) of two or more space the longer term fully autonomous navigational plat-forms. The collaborative operations of satel- capabilities will enable classes of missions which lite formations or coordinated surface rovers op- would otherwise not be possible due to round-trip erations with orbiting spacecraft are other mission light time. Investment in the following specific applications enabled by relative navigation. The technologies will be needed: autonomous naviga- specific component level technologies to bede- tion system architectures and techniques, autono- veloped here include, but may not be limited to, mous navigational planning and optimization al- the following: high resolution/high frame rate vis- gorithms to include highly-reliable approaches for ible and infrared imaging sensors, high speed sen- fault management, sensors for on-board auton- sor data processing electronics, precision narrow- omous navigation, navigation filter algorithms, beam laser rangefinder sensors, navigation filters on-board maneuver planning and sequencing al- (e.g., adaptive filters) and associated algorithms to gorithms, fault-tolerant attitude control systems sort and selectively weight data from multiple rel- for autonomously orienting the platform, effi- ative sensor input sources, mid-to-short range RF cient autonomous navigation system verification or optical intra-spacecraft communications sys- and validation methodologies and ground-based tems for transmission of relative navigation state Hardware-in-the-Loop systems testbed, and in- information and other data between the cooper- space demonstration testbeds. ating spacecraft. Next Generation Sensors/Vision Processing Autonomous Precision Formation Flying Systems: Specific technologies to be developed in- PNT: This system capability builds upon and co- clude optical navigational sensor hardware (such alesces several of the PNT technologies previously as high resolution flash LIDAR sensors, visible described in this Section. The supporting technol-

DRAFT TA05-17 Table 5. Mapping of PNT tasks into the Top Technical Challenges 1 Remove Comm. 2 Remove Nav. 3 Minimize Im- 4 Minimize 5 Integrity & 6 Lower Life- as a Constraint as a Constraint pact of Latency user burden Assurance cycle Cost Time Keeping X Time Distribution X X X Onboard Autonomous Navigation X X and Maneuvering Systems Next Generation Sensors/ Vision Processing Systems X X Relative and Proximity Navigation X X Autonomous Precision Formation X X X Flying PNT Autonomous Approach and Landing X X ogies include differential (relative) navigation, sen- have accomplished. This is a system-level capabil- sors/vision processing systems, space clocks and ity built strongly, but not solely, upon the sever- time/frequency distribution systems, on-board al of the PNT technologies cited above that en- system navigation and autonomous or-bit/atti- able Autonomous Maneuvering, Sensors/Vision tude maneuvering. In this technology “push” case Processing Systems, and On-Board Navigation. much higher level of PNT performance is needed Sensors and algorithms for path planning and op- to satisfy the stringent Precision Formation Flying timization, constraint handling, integrated sys- (PFF) requirements imposed by en-visioned dis- tem health management, fault management (e.g., tributed observatories such as planet-finding in- FDIR), event sequencing, optimal resource allo- terferometers. Advances in PNT technologies are cations, collaborative sensor fusion, sensor image necessary but not sufficient to enable an autono- motion compensation and processing, pattern rec- mous PFF capability for NASA. The PNT tech- ognition/pattern matching, hazard search and de- nologies sought are for autonomous planning and tection strategies, feature (e.g., hazards) location optimization algorithms, higher performance rel- and mapping, high performance inertial sensors ative navigation sensors, lower noise, higher speed and celestial sensors, accurate and fast converg- sensor processing electronics and enhanced rela- ing vehicle state estimation filters and for adaptive tive navigation filters. These technology develop- flight control systems that provide precise and ag- ments should be phased to attain TRL 6 by 2022. ile maneuvering. An opportunity for in-space validation of an inte- One other particular technology area that has grated PFF PNT system will then need to be iden- synergy between the navigation on and around tified prior to the PFF IOC date we set of 2025. NEO/Planetary bodies as well as conducting sci- Autonomous Approach and Landing: An inte- entific surveys is the development of a new gen- grated ensemble of active and passive optical and eration of high performance gravimetric/gravi- RF sensor hardware with supporting real-time vi- ty gradiometer sensors using emerging cold atom sion processing algorithms will be a fundamental sensor technology. System architectures and sup- part of any autonomous Guidance, Navigation, porting technologies for navigational beacons that and Control (GN&C) system intended to per- aid spacecraft approach and landing are needed. form safe and controlled precision landings on The navigational beacons can be deployed on early or contacts with the surface of any solid body in exploration satellites. Navigational beacons can be the Solar System. Precision terrain-relative naviga- integrated into the precursor satellites which will tion while simultaneously detecting and avoiding be used to map and study planet and NEO sur- surface hazards is a multidisciplinary technology face characteristics. These orbiting beacons can be challenge focused on improving real-time situa- part of a navigation constellation for improved ve- tional awareness and platform responsively in un- hicle positioning during the approach and landing certain operational environments. Technologies mission phase. Likewise, body-based beacon land- that allow an increased reliance on in-situ obser- ing systems derived from GPS pseudolite technol- vations, data fusion, and autonomous PNT will ogies can be used for accurate landing systems. A be sought. Significant investments in technologies pre-landing mission can deploy three to five bea- for vehicle on-board sensing, perception, reason- cons. These beacons can land in rough, unknown ing, planning and decision making will be need- locations using air-bags or parachutes. Through ed well beyond what current technology programs repeated observation, these beacons' positions can

TA05-18 DRAFT Table 6. Mapping of integrated technology tasks into the Top Technical Challenges 1 Remove Comm. 2 Remove Nav. as 3 Minimize Impact 4 Minimize user 5 Integrity & As- 6 Lower Lifecycle as a Constraint a Constraint of Latency burden surance Cost Radio Systems X Ultra Wideband X X Cognitive Networks X X X X Science from the X X Comm Systems Hybrid Optical X X X Comm & Nav Sensors RF/Optical Hy-brid X X X X Technology be precisely determined. With knowledge of bea- Overcoming the Challenges: con location, future landing craft can use precise As depicted in the TASR, this area integrates timing beacons for improved navigation accuracy technologies developed in the other areas with the similar to GPS pseudolites. goal of reducing SWAP and enabling multi-pur- Overlaps and Potential Synergies: There are sev- pose systems while at the same time enhancing eral synergetic PNT technology developments un- mission autonomy. derway at NASA. ESMD and SMD have similar Radio Systems Technology: Exploit technol- navigation interests. Both are pursuing autono- ogy advances in RF communications, PNT, and mous precise landing capability that would sup- space internetworking to develop advanced, inte- port their respective missions. grated space and ground systems that increase per- 2.1.5. Integrated Technologies formance and efficiency while reducing cost. For example, a multipurpose software defined radio Current Status: might be developed that can changes its function Current NASA flight transceivers are capable with mission phase and requirements. of performing communication and radiometrics. Ultra-Wideband Technology: Develop radio However, they are not aware of their environment technology for short-range, high-bandwidth com- and do not react to it. There are only limited net- munications and navigation. For example, a sur- work level capabilities. Ground systems have just face explorer may carry an ultra-wideband trans- begun integrating network functionality. Current- ceiver/subsystem which enables it to (in a single ly, NASA missions can take advantage of the RF burst) communicate with another rover or or- communication link as a science instrument — biter in proximity, determine a precise range to gleaning information about intervening atmo- the other element (positioning), and listen for re- spheres, gravity fields and surface terrains. Li- turns from the same burst to produce a navigation dars have demonstrated the potential for similar map for the terrain in proximity to the rover (nav- capability on optical links. Today, RF and opti- igation). This would not only reduce the mass of cal systems are developed and operated separately, the rover consolidating three functions into a sin- even though there are components that could be gle system, but may also reduce power by using a shared. Modeling and simulation is used today for single burst to perform all three functions. research and development of communication and Cognitive Networks: Develop a system in navigation systems. Finally, the location and sta- which each node is dynamically aware of the state tus of our Astronauts and their implements is de- and configuration of the other nodes. Today, most termined through manual means on the ground. of the decisions in space communications and Major Challenges: navigation today are made on the ground. Com- Challenges include reducing the user burden munications and navigation subsystems on future and ground infrastructure through integration missions should interpret information about their of technologies, reducing costs through innova- situation on their own, understand their options, tive systems-level analysis, exploiting optical com- and select the best means to communicate or navi- munication links as science instruments while in- gate. For example, a node in such a network might creasing performance over the RF equivalent and be aware of the positions and trajectories of all increasing the flexibility of communication and other nodes, inferring this entirely through net- navigation systems. work communications and modeling.

DRAFT TA05-19 Science from the Communications System: mission. These are inherently risky investments Enhance the use of RF communications systems with a high probability of failing to achieve their to perform science measurements. Develop the goal—but a very high payoff if they are success- capability to use optical communication links to ful. Technologies that show promise will be tran- make science measurements. Consider using in sitioned to the appropriate communications and combination to improve accuracy. Expand the navigation sub-element for appropriate infusion spectral width of the signals to enable more infor- into missions or enabling infrastructure. mation about sub-surfaces. In addition, promising Major Challenges: new research indicates that with further technolo- The critical thrust for this technology sub-ele- gy development it may be possible to deter-mine ment is to develop new ways of approaching the the Earth’s wobble using the same technology be- key communications and navigation challenges ing developed for the arraying of TDRSS satel- that radically improves the performance. Changes lites. This would provide a continuous real-time should typically be several orders of magnitude in measurement of the wobble as a by-product of increased performance or decreased user burden tracking TDRSS with this new technology. to be considered. Hybrid Optical Communication and Naviga- Overcoming the Challenges: tion Systems: These are sensor systems that are As depicted in the TASR, this area provides in- dual use in nature providing a synergistic benefit novations and game-changing solutions that will to both communication and navigation functions. provide mission planners and scientists freedom Innovative approaches could include exploiting an to develop and implement more complex mis- optical communications terminal to perform nav- sions and enable new science and exploration igational measurements such as star sighting, or goals. Several revolutionary concepts that could a star tracker technology developed to communi- enable new classes of missions have been identi- cate at very high data rates. Such advances will de- fied are presented as examples of possible tasks. crease the SWAP burden to users. X-Ray Navigation: RF/Optical Hybrid Technology: The XNAV concept uses a Optimize collection of pulsars—stellar “lighthouses”—as a the architecture and integrated components into time and navigation standard just like the atomic a system that can be used to support hybridized clocks of the GPS. Unlike GPS satellites, XNAV RF and optical communications in the same as- pulsars are distributed across the Galaxy, provid- set, in diverse atmospheric (weather) and in-space ing an infrastructure of precise timing beacons conditions. This includes both the electronics and that can support navigation throughout the Solar the complex integration of collinear antenna and system. Since their discovery in 1967, pulsars have weather elements within the system. Potential been envisioned as a tool for deep space naviga- benefits include SWAP savings and provision of tion. An XNAV system measures the arrival times an RF beacon for acquisition and pointing. of pulses from pulsars through the detection of in- Overlaps and Potential Synergies: dividual X-ray photons. By its very nature, we expect many sources will X-ray Communications: Space-based commu- exist within NASA for the elemental technologies nications can benefit dramatically from techno- that will be integrated in this area. logical mastery of the x-ray portion of the spec- 2.1.6. Revolutionary Concepts Current Status: Most prior NASA investments in communications and navigation have been in evolutionary improvements and in technologies that are based on electromagnetic principles. Additionally all these systems have a heavy dependence on Earth based services and references. The Agency will continue to invest in pushing the advancement of traditional communications and navigation technologies to meet future mission needs. However, this roadmap also provides a framework to identify revolutionary concepts for potential development. None of these technologies are “pulled” by any future Figure 10. Notional Xnav Architecture TA05-20 DRAFT trum. Fundamentally, two major advantages of quantum entanglement has been demonstrated x-rays (relative to optical, microwave, or radio-fre- at a few tens of kilometers, long-range commu- quency technologies) should be exploited. First, nications face critical challenges. High flux single the short wavelength offers very low divergences, photon sources as well as entangled photon sourc- which has the potential to lower requirements on es need significant development in order to en- SWAP relative to longer-wavelength technologies, able long-range communications. NASA should and to provide secure inter-satellite communica- at minimum stay abreast with the research in this tions. Second, the exceedingly high carrier fre- area to determine if the purported ad-vantages quency means significantly larger band-widths for make sense for space applications (e.g. no antenna information transmission if technologies for mod- needed, no broadcast power, very secure with high ulating x-rays are further developed. data rates, not line of sight, etc). Neutrino-based Navigation and Tracking: Superconducting Quantum Interference Fil- Neutrinos are small near light speed particles ter Microwave Amplifier: This revolutionary with no electric charge. Neutrinos can be gener- concept represents a significant paradigm shift ated through nuclear reactors or particle acceler- by using magnetic field detection instead of elec- ators. Detection of neutrinos however, currently tric field detection and capitalizes on techniques requires massive detectors made of thousands of demonstrated in the sensors community. From a tons of liquid buried in the ground. Since Neu- fundamental physics point of view, the magnetic trinos can travel through most matter, they could field detection process holds promise for a signif- be used for long-distance signaling when line-of- icant advantage in sensitivity. This concept incor- sight cannot be guaranteed. A possible ranging porates a Superconducting Quantum Interference method using neutrinos is to modulate the neutri- Device array for detecting extremely weak mag- no output from a nuclear reactor or particle accel- netic fields to enable a new type of signal detec- erator on a spacecraft and detect this output on an tion process. Though fundamental principles have Earth base station. The modulation would encode already been demonstrated, it is not known how timing information from an atomic clock syn- much of the theoretical sensitivity improvement chronized to Earth, which can be used to calcu- can be realized. Integration of a “flux concentra- late range. NASA, and North Carolina State Uni- tor” at frequencies of interest to NASA and a prac- versity have demonstrated the use of neutrinos for tical Superconducting Quantum Interference Fil- communications. ter has not been demonstrated. Issues such as flux QKD/Quantum Key Distribution: Encryp- motion within the superconducting film, which tion schemes entail distribution of a secret key reduces sensitivity, and system benefits with the among legitimate users and as such are suscepti- refrigeration system included need to be assessed. ble to interception by an unwanted eavesdropper. Reconfigurable Large Apertures: While traditional encryption schemes and codes The vision is to form large space apertures us- can be compromised and/or intercepted, QKD ing constellations of nanosat systems. This will promises absolute secure transmission of the key require advances in nanotechnologies, semicon- codes that are essential to encrypt messages with ductor processors, computing architectures, ad- tamper proof information assurance. A quantum vanced materials power and propulsion, minia- communications channel is inherently se-cure turized communications components, adhoc/ since the mere act of observing the communica- wireless network protocols, and cognitive swarm tions channel will be apparent to both par-ties. operations. While it is acknowledged that other government agencies have the technical lead in the investi- 3. Interdependency with gation of this concept, it would be of value for Other Technology Areas NASA to be cognizant of the advances of QKD The Table below exhibits the identified area of and quantum entanglement as a potential step- synergy or overlap with the other Technology Ar- ping stone for quantum communications. eas. Areas 4, 8, 11, and 13 are where Team 5 be- Quantum Communications: This is the art of lieves there may be the most overlap. transferring quantum states (which encode information) between two points. It should be not- 4. Possible Benefits to ed that there is significant debate in the scientif- Other National Needs ic community as to whether this technology will enable faster than light communications. While Many technology advances in space communi-

DRAFT TA05-21 Technology Area Synergy or Overlap 2 In-Space Propulsion Autonomous GNC maneuvers; Solar Sail Propulsion 3 Space Power and Energy Storage Power beaming; Power antennas 4 Robotics and Telerobotics Navigation sensors; Autonomous GNC; Internetworking; Navigation for flying and submersible robots; Near real-time communications with the public; Human/Robotic interaction 6 Human Health, Life Support and Habitation Systems Very high bandwidth communication for telemedicine; RFID asset tracking; Software uploads 7 Human Exploration Destination Systems Very high bandwidth communication for telemedicine; RFID asset tracking; Software uploads 8 Science Instrument, Observatories, and Sensor Systems Detectors; Telescopes/Antennas; Enabling communications; Science using the communication system; Onboard wireless avionics; Multi-purpose (science, comm. and nav) sensors and systems 9 Entry, Descent, and Landing Systems Reentry Communications; Precision landing 10 Nano Technology Nano transceivers 11 Modeling, Simulation, and Information Processing Atmospheric models; High performance computing platform; Networking; Data compression 12 Materials, Structure and Mechanical Systems, and Large apertures; Manufacturing Lightweight materials 13 Ground and Launch System Processing Telemetry systems using new spectrum; Secure access; On-demand frequency allocation (cognitive radios); Adaptive data compression; Intelligent network topologies (DTN); Interspacecraft communications; Universal communications beacon for hailing; Range safety; Space-based range; Comm through plume cations technology are transferable to the com- the National Science Foundation (the major US mercial communication environments. For ex- sponsor of the Square Kilometer Array). Many ample, spectrum efficient technology is a prime other non-profit and academic organizations can concern of the telecommunications industry and bene-fit from space communication technology those US Government agencies that manage spec- development through challenging opportunities trum. Similarly, advanced networking that can for researchers to contribute to the development autonomously deal with communications disrup- efforts directly or through educational outreach tions has potential terrestrial commercial applica- programs. tions as part of the internet. In general, communi- Sharing the NASA adventure with all American cation technology developed for space applications citizens is a top goal for NASA. Space communi- can be implemented in the commercial sec-tor, cations technology development can enable in the even though the actual spectrum frequencies may future the average citizen to view from his living differ. This applies to both the commercial ter- room, in live, full motion, three dimensional vid- restrial and space communication sectors. In ad- eo, the exploration activities of our robots and as- dition, many commercially developed communi- tronauts on their missions of discovery. cation technologies can be implemented in NASA NASA space communications technology has systems and can be used directly or modified for traditionally been of interest to other US Govern- space use. ment agencies. This is evidenced by the fact that Because of the commonality of many of the many past space communication technology de- components and methods, NASA’s communica- velopments have been joint projects with other tion technology has always been synergistic with agencies. There is reason to believe that this trend the radio astronomy community, including the will continue. For example, in the recent “Report National Radio Astronomy Observatory, and on Technology Horizons – A Vision for Air Force

TA05-22 DRAFT Science & Technology” Are many technology ar- NEO Near Earth Object eas of interest that are common with the areas cit- PAT Pointing, Acquisition, and Tracking ed in this roadmap such as: laser communications, PFF Precise Formation Flying secure RF links, dynamic spectrum access, quan- PNT Position, Navigation, and Time tum key distribution, as well as many others. Also, POD Precision Orbit Determination cybersecurity is an area of critical importance to all PSK Phase Shift Keying agencies, has been identified by the President as an QAM Quadrature Amplitude Modulation area of R&D to be pursued by all US Government SCaN Space Communications and Navigation agencies and will be a driving requirement as we SMD Science Mission Directorate extend the terrestrial Internet into space. There- SoA State of the Art fore, as the roadmap in this document is executed SOMD Space Operations Mission Directorate there will be continuous dialogue with other US SWAP Size, Weight and Power Government agencies to seek out areas of mutual TABS Technology Area Breakdown Structure interest and collaborative opportunities. TASR Technology Area Strategic Roadmap TDRSS Tracking and Data Relay Satellite System Acronyms UWB Ultra Wide Band ALHAT Autonomous Landing and Hazard VLBI Very Long Baseline Interferometry Avoidance Technology XNAV X-ray Navigation ATP Authority to proceed AO Announcement of Opportunity Acknowledgements AU Astronomical Unit Delta-DOR Delta Differential One-Way Ranging The NASA technology area draft roadmaps were DESDynI Deformation, Ecosystem Structure developed with the support and guidance from and Dynamics of Ice the Office of the Chief Technologist. In addition DINET Deep Impact Networking Experiment to the primary authors, major contributors for the DOT Deep Space Optical Terminal TA05 roadmap included the OCT TA05 Road- DSN Deep Space Network mapping POC, Karen McNamara; the reviewers DTN Disruption (or Delay) Tolerant Networking provided by the NASA Center Chief Technolo- ECLS Environmental Control and Life Support gists and NASA Mission Directorate representa- EHS Environmental Health System tives, and Kimberly Cashin, document and data- ESMD Exploration Systems Mission Directorate base manager. GEONS GPS-Enhanced Onboard Navigation System GHz Giga Hertz GMSK Gaussian Minimum Shift Keying GN&C Guidance Navigation and Control GNSS Global Navigation Satellite System GPS Global Positioning System GRAIL Gravity Recovery and Interior Laboratory GRO Gamma-Ray Observatory IOC Initial Operational Capability IP Internet Protocol ISS International Space Station JPL Jet Propulsion Laboratory LADEE Lunar Atmosphere and Dust Environment Explorer LEO Low Earth Orbit LIDAR Light Detection And Ranging LLCD Lunar Laser Communications Demonstration LST Life Support Technologies MMS Magnetospheric MultiScale MRO Mars Reconnaissance Orbiter MVP Mass, Volume, Power NEN Near Earth Network

DRAFT TA05-23 November 2010

National Aeronautics and Space Administration

NASA Headquarters Washington, DC 20546 www.nasa.gov TA05-24 DRAFT