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Top Technical Challenges and
High-Priority Technologies by Roadmap

TECHNOLOGY EVALUATION PROCESS AND CRITERIA

A set of criteria was established by the steering committee to enable the prioritization of technologies within each and, ultimately, among all of the technology areas of the NASA technology roadmaps.1 These criteria were chosen to capture the potential benefits, breadth, and risk of the various technologies and were used as a guide by both the panels and the steering committee to determine the final prioritization of the technologies. In addition to the primary criteria used to prioritize the technologies, an additional set of secondary descriptive factors were also assessed for each technology. These descriptive factors were added to provide a complete picture of the panels’ assessments of the technologies and assisted in the evaluations.

Broad community input was solicited through a public website, where more than 240 public comments were received on the draft roadmaps using the established steering committee criteria and other descriptive factors. The public and panels were given the same rubrics to evaluate the technologies so that the various inputs could be more fairly compared against each other. These views, along with those expressed during the public workshops, were taken into account by the panel members as they assessed the technologies. The panels then came to a consensus view for each criterion for each technology.

In evaluating and prioritizing the technologies identified, the steering committee made a distinction between technology development and engineering development. Technology development, which is the intended focus of the draft roadmaps, addresses the process of understanding and evaluating capabilities needed to improve or enable performance advantages over current state-of-the-art space systems. Technologies of interest include both hardware and software, as well as testing and evaluation of hardware (from the component level to the systems level) and software (including design tools) at various levels of technology readiness for application in future space systems. In contrast, engineering development, which generally attempts to implement and apply existing or available technology, is understood for the purposes of this study to be hardware, software, design, test, verification, and validation of systems in all phases of NASA’s acquisition process. The high-priority technologies do not include items for which engineering development is the next step in advancing capabilities.

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1The draft space technology roadmaps are available at http://www.nasa.gov/offices/oct/strategic_integration/technology_roadmap.html.



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2 Top Technical Challenges and High-Priority Technologies by Roadmap TECHNOLOGY EVALUATION PROCESS AND CRITERIA A set of criteria was established by the steering committee to enable the prioritization of technologies within each and, ultimately, among all of the technology areas of the NASA technology roadmaps. 1 These criteria were chosen to capture the potential benefits, breadth, and risk of the various technologies and were used as a guide by both the panels and the steering committee to determine the final prioritization of the technologies. In addition to the primary criteria used to prioritize the technologies, an additional set of secondary descriptive factors were also assessed for each technology. These descriptive factors were added to provide a complete picture of the panels’ assessments of the technologies and assisted in the evaluations. Broad community input was solicited through a public website, where more than 240 public comments were received on the draft roadmaps using the established steering committee criteria and other descriptive factors. The public and panels were given the same rubrics to evaluate the technologies so that the various inputs could be more fairly compared against each other. These views, along with those expressed during the public workshops, were taken into account by the panel members as they assessed the technologies. The panels then came to a consensus view for each criterion for each technology. In evaluating and prioritizing the technologies identified, the steering committee made a distinction between technology development and engineering development. Technology development, which is the intended focus of the draft roadmaps, addresses the process of understanding and evaluating capabilities needed to improve or enable performance advantages over current state-of-the-art space systems. Technologies of interest include both hardware and software, as well as testing and evaluation of hardware (from the component level to the systems level) and software (including design tools) at various levels of technology readiness for application in future space systems. In contrast, engineering development, which generally attempts to implement and apply existing or available technology, is understood for the purposes of this study to be hardware, software, design, test, verification, and validation of systems in all phases of NASA’s acquisition process. The high-priority technologies do not include items for which engineering development is the next step in advancing capabilities. 1 The draft space technology roadmaps are available at http://www.nasa.gov/offices/oct/strategic_integration/technology_roadmap.html. 16

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17 TOP TECHNICAL CHALLENGES AND HIGH-PRIORITY TECHNOLOGIES BY ROADMAP Top Technical Challenges The panels identified a number of challenges for each technology area that should be addressed for NASA to improve its capability to achieve its objectives. These top technical challenges were generated to provide some focus for technology development and to assist in the prioritization of the level 3 technologies. The challenges were developed to identify the general needs NASA has within each technology area, whereas the technologies themselves address how those needs will be met. Once the top technical challenges were identified, the panels then determined the relative importance of the challenges within each technology area to put them in priority order. Descriptive Factors The steering committee identified three descriptive factors that helped characterize each technology. While these factors were not primary in the determination of technology prioritization, they did assist in generating a better understanding of the current status or state of the art of the technology. • Technology Readiness Level (TRL): This factor describes the current state of advancement of the tech - nology using NASA’s TRL scale. The TRL scale is defined in Table 2.1. It was determined that TRL should not be a basis for prioritizing technologies, as NASA should be investing across all levels of technology readiness. In assessing TRL levels, the panels were directed to evaluate the most promising developments that should receive attention. For example, electric propulsion systems are commonly used today, so as a whole, they would be assessed as TRL 9; however, the promising area of advancement of high power electric propulsion is less advanced, and thus 2.2.1 Electric Propulsion was assessed as TRL 3. • Tipping Point: The tipping point factor was used to determine if the technology was at a state such that a relatively small additional effort (compared to that which advanced the technology to its current state) could produce a significant advance in technology readiness that would justify increasing the priority associated with this technology. • NASA Capabilities: This factor captured how NASA research in this technology aligns with the exper- tise, capabilities, and facilities of NASA and/or other organizations cooperating with NASA in this area. It also indicated how much value NASA research in this technology would add to ongoing research by other organizations. This was not a primary consideration in assessing which technologies should be prioritized. Instead it was a factor in considering whether the technology should be developed by NASA, or if NASA should support other current efforts. The factor also addressed whether or not NASA should invest in improving its own capability for pursuing the high-priority technologies. Evaluation Criteria The steering committee identified three main criteria on which the technologies were to be judged for evalua - tion. The three criteria were benefit, alignment with NASA’s goals and objectives, and technical risk and challenge. Each of these is described in further detail below. For the latter two criteria, three further sub-criteria were created to assist in evaluating the technologies. For each evaluated criterion or sub-criterion, a set of four (or in one case five) grades or bins were established, and the public and panel members were asked to determine what grade each technology should receive for that criterion. For consistency, a set of definitions were generated for each grade. The grading definitions were provided as guidelines to help the panel and steering committee members assign an appropriate range of grades necessary to prioritize the technologies in question. They were generated such that most technologies would be placed into one of the middle bins, while placement at the upper/lower bounds would need significant justification. The grades were assigned numeric scores on a non-linear scale (e.g., 0-1-3-9) to accentuate the spread of the summed

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18 NASA SPACE TECHNOLOGY ROADMAPS AND PRIORITIES TABLE 2.1 NASA Technology Readiness Levels TRL Definition Hardware Description Software Description Exit Criteria 1. Basic principles Lowest level of technology Scientific knowledge Scientific knowledge Peer reviewed observed and readiness. Scientific research generated underpinning generated underpinning publication of research reported. begins to be translated hardware technology basic properties of underlying the proposed into applied research and concepts/applications. software architecture concept/application. development. Examples might and mathematical include paper studies of a formulation. technology’s basic properties. 2. Technology Invention begins. Once basic Invention begins, Practical application Documented description concept and/ principles are observed, practical practical application is identified but of the application/ or application applications can be invented. is identified but is speculative, no concept that addresses formulated. The application is speculative, is speculative, no experimental proof or feasibility and benefit. and there is no proof or experimental proof or detailed analysis is detailed analysis to support the detailed analysis is available to support assumption. Examples are still available to support the the conjecture. limited to paper studies. conjecture. Basic properties of algorithms, representations and concepts defined. Basic principles coded. Experiments performed with synthetic data. 3. Analytical and At this step in the maturation Analytical studies Development of limited Documented analytical/ experimental critical process, active research and place the technology functionality to validate experimental results function and/or development (R&D) is initiated. in an appropriate critical properties validating predictions of characteristic proof This must include both analytical context and laboratory and predictions using key parameters. of concept. studies to set the technology demonstrations, non-integrated software into an appropriate context modeling and components. and laboratory-based studies simulation validate to physically validate that the analytical prediction. analytical predictions are correct. These studies and experiments should constitute “proof-of- concept” validation of the applications/concepts formulated at TRL 2. 4. Component and/ Following successful “proof- A low fidelity system/ Key, functionally Documented or breadboard of-concept” work, basic component breadboard critical software test performance validation in technological elements must is built and operated components are demonstrating agreement laboratory be integrated to establish that to demonstrate integrated, and with analytical environment. the pieces will work together basic functionality functionally predictions. Documented to achieve concept-enabling and critical test validated, to establish definition of relevant levels of performance for a environments, and interoperability and environment. component and/or breadboard. associated performance begin architecture This validation must be devised predictions are defined development. Relevant to support the concept that was relative to the final environments defined formulated earlier and should operating environment. and performance in this also be consistent with the environment predicted. requirements of potential system applications. The validation is relatively “low-fidelity” compared to the eventual system: it could be composed of ad hoc discrete components in a laboratory.

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19 TOP TECHNICAL CHALLENGES AND HIGH-PRIORITY TECHNOLOGIES BY ROADMAP TABLE 2.1 Continued TRL Definition Hardware Description Software Description Exit Criteria 5. Component and/ At this level, the fidelity of the A medium fidelity End-to-end software Documented or breadboard component and/or breadboard system/component elements implemented test performance validation in relevant being tested has to increase brassboard is built and and interfaced with demonstrating agreement environment. significantly. The basic operated to demonstrate existing systems/ with analytical technological elements must overall performance in simulations conforming predictions. Documented be integrated with reasonably a simulated operational to target environment. definition of scaling realistic supporting elements environment with End-to-end software requirements. so that the total applications realistic support system, tested in (component-level, subsystem- elements that relevant environment, level, or system-level) can demonstrates overall meeting predicted be tested in a “simulated” or performance in critical performance. somewhat realistic environment. areas. Performance Operational predictions are environment made for subsequent performance development phases. predicted. Prototype implementations developed. 6. System/ A major step in the level of A high fidelity system/ Prototype Documented subsystem model fidelity of the technology component prototype implementations of the test performance or prototype demonstration follows the that adequately software demonstrated demonstrating agreement demonstration completion of TRL 5. At TRL addresses all critical on full-scale realistic with analytical in a relevant 6, a representative model or scaling issues is built problems. Partially predictions. environment. prototype system or system, and operated in a integrate with existing which would go well beyond ad relevant environment hardware/software hoc, “patch-cord,” or discrete to demonstrate systems. Limited component level breadboarding, operations under documentation would be tested in a relevant critical environmental available. Engineering environment. At this level, if conditions. feasibility fully the only relevant environment is demonstrated. the environment of space, then the model or prototype must be demonstrated in space. 7. System prototype Prototype near or at planned A high fidelity Prototype software Documented demonstration in operational system. TRL 7 is engineering unit exists having all key test performance an operational a significant step beyond TRL that adequately functionality available demonstrating agreement environment. 6, requiring an actual system addresses all critical for demonstration and with analytical prototype demonstration in a scaling issues is built test. Well integrated predictions. space environment. The prototype and operated in a with operational should be near or at the scale of relevant environment hardware/software the planned operational system, to demonstrate systems demonstrating and the demonstration must take performance in the operational feasibility. place in space. Examples include actual operational Most software bugs testing the prototype in a test environment and removed. Limited bed. platform (ground, documentation airborne, or space). available. continued

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20 NASA SPACE TECHNOLOGY ROADMAPS AND PRIORITIES TABLE 2.1 Continued TRL Definition Hardware Description Software Description Exit Criteria 8. Actual system Technology has been proven to The final product in All software has been Documented test competed and work in its final form and under its final configuration thoroughly debugged performance verifying “flight qualified” expected conditions. In almost is successfully and fully integrated analytical predictions. through test and all cases, this level is the end demonstrated through with all operational demonstration. of true system development for test and analysis for its hardware and software most technology elements. This intended operational systems. All user might include integration of environment and documentation, new technology into an existing platform (ground, training documentation, system. airborne, or space). and maintenance documentation completed. All functionality successfully demonstrated in simulated operational scenarios. Verification and Validation (V&V) completed. 9. Actual system Actual application of the The final product is All software has Documented mission flight proven through technology in its final form and successfully operated been thoroughly operational results. successful mission under mission conditions, such as in an actual mission. debugged and fully operations those encountered in operational integrated with all test and evaluation. In almost operational hardware/ all cases, this is the end of the software systems. last “bug fixing” aspects of true All documentation system development. This TRL has been completed. does not include planned product Sustaining software improvement of ongoing or engineering reusable systems. support is in place. System has been successfully operated in the operational environment. SOURCE: NASA Procedural Requirements 7120.8, Appendix J (http://nodis3.gsfc.nasa.gov/displayDir.cfm?Internal_ID= N_PR_7120_0008_ &page_name=AppendixJ) and NASA Procedural Requirements 7123.1A, Table G.19 (http://esto.nasa.gov/ files/TRL.dochttp:/nodis3.gsfc. nasa.gov/displayDir.cfm?Internal_ID=N_PR_7123_001A_&page_name=AppendixG). final scores. Higher numeric scores implied greater ability to meet NASA’s goals. Negative numbers indicated characteristics that were not desirable. Benefit: Would the technology provide game-changing, transformational capabilities in the timeframe of the study? What other enhancements to existing capabilities could result from development of this technology? 1. The technology is unlikely to result in a significant improvement in performance or reduction in life cycle cost of missions during the next 20 years. Score: 0 2. The technology is likely to result in (a) a minor improvement in mission performance (e.g., less than a 10 percent reduction in system launch mass); (b) a minor improvement in mission life cycle cost; or (c) less than an order of magnitude increase in data or reliability of missions during the next 20 years. Score: 1 3. The technology is likely to result in (a) a major improvement in mission performance (e.g., a 10 percent to 30 percent reduction in mass); or (b) a minor improvement in mission life cycle cost or an order of magnitude increase in data or reliability of missions during the next 20 years. Score: 3

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21 TOP TECHNICAL CHALLENGES AND HIGH-PRIORITY TECHNOLOGIES BY ROADMAP 4. The technology is likely to provide game-changing, transformational capabilities that would enable important new projects or missions that are not currently feasible during the next 20 years. Score: 9 Alignment: Three sub-criteria were created to evaluate the alignment with NASA’s goals and objectives criterion. Alignment with NASA Needs: How does NASA research in this technology improve NASA’s ability to meet its long-term needs? For example, which mission areas and which missions listed in the relevant roadmap would directly benefit from development of this technology, and what would be the nature of that impact? What other planned or potential missions would benefit? 1. Technology is not directly applicable to NASA. Score: 0 2. Technology will impact one mission in one of NASA’s mission areas. Score: 1 3. Technology will impact multiple missions in one of NASA’s mission areas. Score: 3 4. Technology will impact multiple missions in multiple NASA mission areas. Score: 9 Alignment with Non-NASA Aerospace Technology Needs: How does NASA research in this technology improve NASA’s ability to address non-NASA aerospace technology needs? 1. Little or no impact on aerospace activities outside of NASA’s specific needs. Score: 0 2. Impact will be limited to niche roles. Score 1 3. Will impact a large subset of aerospace activities outside of NASA’s specific needs (e.g., commercial spacecraft). Score: 3 4. Will have a broad impact across the entire aerospace community. Score: 9 Alignment with Non-Aerospace National Goals: How well does NASA research in this technology improve NASA’s ability to address national goals from broader national perspective (e.g., energy, transportation, health, environmental stewardship, or infrastructure)? 1. Little or no impact outside the aerospace industry. Score: 0 2. Impact will be limited to niche roles. Score: 1 3. Will be useful to a specific community outside aerospace (e.g., medicine). Score: 3 4. Will be widely used outside the aerospace community (e.g., energy generation or storage). Score: 9 Technical Risk and Challenge: Three sub-criteria were created to evaluate the technical risk and challenge cri - terion. In this criterion, the grades created were not as straightforward as those for benefit and alignment. They were developed to capture the steering committee’s view on the appropriate risk posture for NASA technology developments. Technical Risk and Reasonableness: What is the overall nature of the technical risk and/or the reasonableness that this technology development can succeed in the timeframe envisioned? Is the level of risk sufficiently low that industry could be expected to complete development of this technology without a dedicated NASA research effort, or is it already available for commercial or military applications? Regarding the expected level of effort and timeframe for technology development: (a) are they believable given the complexity of the technology and the technical challenges to be overcome; and (b) are they reasonable given the envisioned benefit vis-à-vis possible alternate technologies? 1. The technical risk associated with development of this technology is very low, such that it is feasible for industry or a specific NASA mission office to complete development (without additional NASA technology funding if a mission need arises). Score: 1

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22 NASA SPACE TECHNOLOGY ROADMAPS AND PRIORITIES 2. The technical risk associated with development of this technology is low, and the likely cost to NASA and the timeframe to complete technology development are not expected to substantially exceed those of past efforts to develop comparable technologies. Score: 3 3. The technical risk associated with development of this technology is moderate to high, which is a good fit to NASA’s level of risk tolerance for technology development, but the likely cost to NASA and the timeframe to complete technology development are expected to substantially exceed those of past efforts to develop comparable technologies. Score: 3 4. The technical risk associated with development of this technology is moderate to high, which is a good fit to NASA’s level of risk tolerance for technology development, and the likely cost to NASA and the time - frame to complete technology development are not expected to substantially exceed those of past efforts to develop comparable technologies. Score: 9 5. The technical risk associated with development of this technology is extremely high, such that it is unreasonable to expect any operational benefits over the next 20 years without unforeseen revolutionary breakthroughs and/or an extraordinary level of effort. Score: 1 Sequencing and Timing: Is the proposed timing of the development of this technology appropriate relative to when it will be needed? What other new technologies are needed to enable the development of this technology, have they been completed, and how complex are the interactions between this technology and other new technologies under development? What other new technologies does this technology enable? Is there a good plan for proceed - ing with technology development? Is the technology development effort well connected with prospective users? 1. This is an extremely complex technology and/or is highly dependent on multiple other projects with interfaces that are not well thought out or understood. Score: –9 2. The development of this technology is just roughly sketched out and there are no clearly identified users (i.e., missions). Score: –3 3. There is a clear plan for advancing this technology. While there is an obvious need, there are no specifi - cally identified users. Score: –1 4. There is a clear plan for advancing this technology, there is an obvious need, and joint funding by a user seems likely. Score: +1 Time and Effort to Achieve Goals: How much time and what overall effort are required to achieve the goals for this technology? 1. National endeavor: Likely to require more than 5 years and substantial new facilities, organizations, and workforce capabilities to achieve; similar to or larger in scope than the Shuttle, Manhattan Project, or Apollo Program. Score: –9 2. Major project: Likely to require more than 5 years and substantial new facilities to achieve; similar in scope to development of the Apollo heat shield or the Orion environmental systems. Score: –3 3. Moderate effort: Can be achieved in less than 5 years with a moderately sized (less than 50 people) team (e.g., Mars Pathfinder’s airbag system). Score: –1 4. Minimal effort: Can be achieved in a few years by a very small (less than 10 people) team (e.g., graduate student/faculty university project). Score: 0 Evaluation Methodology The individual panels were tasked with binning the individual technologies into high, medium, and low priority for level 3 technologies. This was done primarily by grading the technologies using the criteria described above. The panels generated a weighted decision matrix based on quality function deployment (QFD) techniques for each technology area. In this method, each criterion was given a numerical weight by the steering committee, described

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23 TOP TECHNICAL CHALLENGES AND HIGH-PRIORITY TECHNOLOGIES BY ROADMAP TABLE 2.2 Numerical Weighting Factors Given to Evaluation Criteria in Panel Assessments Criterion Numerical Weight Benefit (27) 27 Alignment (9) Alignment with NASA needs 5 Alignment with non-NASA aerospace needs 2 Alignment with non-aerospace national goals 2 Technical risk and challenge (18) Technical risk and reasonableness 10 Sequencing and timing 4 Time and effort 4 below. By multiplying the panel grades by the criteria weighting factor and summing the results, a single score was calculated for each technology. The steering committee based the criteria weighting on the importance of the criteria to meeting NASA’s goals of technology advancement. It determined that the potential benefit of the technology was the most important factor in prioritizing, with the risk and challenges being second, and alignment being third in importance of the three main criteria. To allow for weighting at the sub-criteria level, the steering committee assigned a total weighting of 9 to alignment, 18 to risk and challenges, and 27 to benefits. It then divided those values among the sub-criteria to generate the values shown in Table 2.2. This method provided an initial assessment of how technologies met NASA’s goals via the criteria evaluation. After each panel came to a consensus on the grades for all criteria for each technology, a total QFD score was computed for each technology. Consider the example shown in Figure 2.1. The QFD score for technology 1.1.1 Propellants is computed using the score for each criterion and the corresponding multiplier as follows: 1 × 27 + 3 × 5 + 3 × 2 + 0 × 2 + 3 × 10 – 1 × 4 – 1 × 4 = 70 The technologies were then sorted by their total QFD scores. In Figure 2.1, technology 1.3.1 TBCC has the highest score, and thus it is the highest priority of the three technologies shown. Once the panels had ordered the technologies by their total scores, they then divided the list into high, medium, and low priority technology groups.2 This division was subjectively performed by each panel for each technology area for which it was responsible, seeking where possible natural break points. For instance, in the case of the assessment of TA01, the panel decided that the split between high and medium priority technologies should occur at a score of 150, and that the split between medium and low priority technologies should occur at a score of 90. To add flexibility to the assessment process, the panels were also given the option of identifying key technologies that they believed should be high priority but that did not have a numerical score that achieved a high priority rank. These override technologies were deemed by the panels to be high priority irrespective of the numerical scores. As such, by allowing the panels to use this override provision, the numerical scoring process could be used effectively without the evaluation becoming a slave to it. Based on the raw QFD scoring of the 295 level 3 technologies, 64 were initially classified as high priority, 128 as medium priority, and 103 as low priority. The panels subsequently decided to override the QFD scores to elevate 18 medium priority technologies and 1 low priority technology (6.4.4 Remediation) to the high priority group. The final result was to have 83 high priority technologies, 110 medium 2 The panels were tasked with designating each technology as high, medium, or low priority only. The high-priority technologies are listed in this section of each appendix by QFD score, in descending order; this sequencing may be considered a rough approximation of the rela - tive priority of the technologies within each technology area. Also, this ordering places the override technologies (which were designated as high priority despite their relatively low QFD scores) as least among the high-priority technologies, although that is not necessarily the case.

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24 NASA SPACE TECHNOLOGY ROADMAPS AND PRIORITIES ce ds ds pa ee ee SA os N N SA er g no A gy in d) ch n-N A A lo m ls n- te N d Ti Te No oa No gh en n ith s bl k a d ei es rt th l G ith tw an (W fo na is y pa wi na w rit en ng Ef so l R e ce os t io t rio or nm er e n at e n ci d ea c a an Sc en lP it nm Nm ni lig ef n qu ne e ch FD A en lig lig m Se Pa Te Ti Q B A A A R 27 5 2 2 10 4 4 Multiplier 0/1/3/9 0/1/3/9 0/1/3/9 0/1/3/9 1/3/9 -9/-3/-1/1 -9/-3/-1/0 Benefit Alignment Risk/Difficulty Technology Name 1 3 3 0 3 -1 -1 70 L 1.1.1. (Solid Rocket) Propellants 1 9 9 0 3 1 -3 112 M 1.2.1. LH2/LOX Based 1.3.1.Turbine Based Combined Cycle (TBCC) 3 9 9 0 3 -3 -3 150 H FIGURE 2.1 Sample QFD matrix, showing three technologies from TA01 and their resulting QFD scores. priority technologies, and 102 low priority technologies. The steering committee believes that the results of the panel scoring validate the design of the QFD scoring process and the decision to allow the panels to override those scores as appropriate. The panels also assessed which of the technologies have the greatest chance of meeting the identified top technical challenges. While many of the technologies within a technology area could potentially address one or more of the challenges, the panels only labeled those where investment would have a major or moderate impact. This assessment was used to verify the proper identification of the high-priority technologies and occasionally as validation for using the override option. Public Workshops A series of workshops were held to solicit input for the members of the community who were interested in contributing to the discussion of the technology roadmaps. The workshops were organized by the various panels and all included speakers specifically invited by the panel members. The workshops were open to the public and included times for open discussion by all members of the audience. The views expressed during the public work - shops were considered by the panel members as they assessed the level 3 technologies. Detailed summaries of each workshop can be found at the end of each roadmap report (the roadmap reports can be found in Appendixes D-Q). Table 2.3 lists information on each public workshop. SUMMARY OF TOP TECHNICAL CHALLENGES AND HIGH-PRIORITY TECHNOLOGIES BY ROADMAP The methods described above were applied to all 14 draft roadmaps by the six technical panels. Using the various forms of public input as well as their own internal deliberations, the study panels produced reports for the steering committee that prioritized the level 3 technologies into high, medium, and low categories; described the value of the high-priority technologies; identified gaps in the draft roadmaps; identified development or schedule changes of the technologies covered; and summarized the public workshop that focused on the draft roadmap. Each panel report, one per draft roadmap, is included as an appendix to this report (see Appendixes D-Q). The top technical challenges and high-priority technologies for each roadmap are summarized below, along with any other high-level summary information for each roadmap. It should be noted that the top technical challenges for each roadmap have been prioritized by the panels and are listed here in priority order. The panels were not instructed to prioritize level 3 technologies, other than to categorize them into high, medium, and low priority “bins.” All high-priority technologies are described below; the order is determined by the QFD score the technology received.

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25 TOP TECHNICAL CHALLENGES AND HIGH-PRIORITY TECHNOLOGIES BY ROADMAP TABLE 2.3 Summary Information on Public Workshops Held on Each Roadmap Roadmap Workshop Date Workshop Location Responsible Panel TA01 Launch Propulsion Systems March 23, 2011 California Institute of Panel 1: Propulsion and Technology, Pasadena, CA Power TA02 In-Space Propulsion Technologies March 21, 2011 California Institute of Panel 1: Propulsion and Technology, Pasadena, CA Power TA03 Space Power and Energy Storage March 24, 2011 California Institute of Panel 1: Propulsion and Technology, Pasadena, CA Power TA04 Robotics, TeleRobotics, and Autonomous March 30, 2011 Keck Center, Washington, DC Panel 2: Robotics, Systems Communication, and Navigation TA05 Communication and Navigation March 29, 2011 Keck Center, Washington, DC Panel 2: Robotics, Communication, and Navigation TA06 Human Health, Life Support, and April 26, 2011 The Lunar and Planetary Panel 4: Human Health Habitation Systems Institute, Houston, TX and Surface Exploration TA07 Human Exploration Destination Systems April 27, 2011 The Lunar and Planetary Panel 4: Human Health Institute, Houston, TX and Surface Exploration TA08 Science Instruments, Observatories, and March 29, 2011 Beckman Center, Irvine, CA Panel 3: Instruments and Sensor Systems Computing TA09 Entry, Descent, and Landing Systems March 23-24, 2011 Beckman Center, Irvine, CA Panel 6: EDL TA10 Nanotechnology March 9, 2011 Keck Center, Washington, DC Panel 5: Materials TA11 Modeling, Simulation, and Information May 10, 2011 Keck Center, Washington, DC Panel 3: Instruments and Technology and Processing Computing TA12 Materials, Structures, Mechanical Systems, March 10, 2011 Keck Center, Washington, DC Panel 5: Materials and Manufacturing TA13 Ground and Launch Systems Processing March 24, 2011 California Institute of Panel 1: Propulsion and Technology, Pasadena, CA Power TA14 Thermal Management Systems March 11, 2011 Keck Center, Washington, DC Panel 5: Materials TA01 Launch Propulsion Systems TA01 includes all propulsion technologies required to deliver space missions from the surface of Earth to Earth orbit or Earth escape, including solid rocket propulsion systems, liquid rocket propulsion systems, air breathing propulsion systems, ancillary propulsion systems, and unconventional/other propulsion systems. The Earth-to-orbit launch industry is currently reliant on very mature technologies, to which only small incremental improvements are possible. Breakthrough technologies are not on the near horizon; therefore research and development efforts will require both significant time and financial investments. TA01 Top Technical Challenges 1. Reduced Cost: Develop propulsion technologies that have the potential to dramatically reduce the total cost and to increase the reliability and safety of access to space. High launch costs currently serve as a major barrier to any space mission, limiting both the number and the scope of NASA’s space missions. Even in light of major monetary investments in launch over the last several decades, the cost of launch has not decreased and in fact continues to increase. Reliability and safety are essential concerns for NASA’s space missions. Finding ways to improve reliability and safety without significantly effect - ing cost is a major technical challenge.

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26 NASA SPACE TECHNOLOGY ROADMAPS AND PRIORITIES 2. Upper Stage Engines: Develop technologies to enable lower cost, high specific impulse upper stage engines suitable for NASA, DOD, and commercial needs, applicable to both Earth-to-orbit and in-space applications. The RL-10 engine is the current upper stage engine in use but is based on 50-year-old technology and is both expensive and difficult to produce. Alternative engine cycles and designs with the promise of reducing cost and improving reliability are a major challenge. Additionally, because high-rate production substantially lowers costs, technologies which are amenable to a wide range of applications are desirable. TA01 High-Priority Technologies Two high-priority technologies were identified from TA-01. In both cases high-priority status was identified because of the wide range of applications that they offered for NASA’s missions. However, a significant number of challenges were also identified for each, and the steering committee believes that it will take decades of research and development and a large and sustained financial investment to makes these technologies feasible. Technology 1.3.1, Turbine Based Combined Cycle (TBCC) Turbine Based Combined Cycle (TBCC) propulsion systems have the potential to combine the advantages of gas turbines and rockets in order to enable lower launch costs and more responsive operations. NASA has been investigating rocket-air breathing cycles for many years, and its commitment to and expertise in hypersonic air breathing cycles is exemplified by NASA’s experimental X-43 program. Technology 1.3.2, Rocket Based Combined Cycle (RBCC) Rocket Based Combined Cycle (RBCC) propulsion systems combine the high specific impulse of the air breathing ramjet and scramjet engines with the high thrust/weight ratio of a chemical rocket. They promise to deliver launch systems with much lower costs than present launch systems. As noted above for TBCC, NASA has been investigating rocket-air breathing cycles for many years, and its commitment to and expertise in hypersonic air breathing cycles is exemplified by NASA’s experimental X-43 program. Additional Comments The development timeline for launch propulsion technologies will be critically dependent on the overall strategy and architecture chosen for exploration and the funding available. Of particular relevance is launch eco - nomics, particularly with regard to the launch rate and the mass of missions being launched. Additionally, there are technologies included in other roadmaps, especially TA02 (In-Space Propulsion) and TA04 (Robotics, Tele- Robotics, and Autonomous Systems) that open the trade space to other architecture options, such as fuel depots requiring on-orbit propellant transfer technologies. For example, one may be able to disaggregate some large space missions to be launched by larger numbers of smaller, lower cost launch vehicles. These technologies may allow more dramatic reductions in launch costs than would specific launch technologies themselves. TA02 In-Space Propulsion Technology TA02 includes all propulsion-related technologies required by space missions after the spacecraft leaves the launch vehicle from Earth, consisting of four level 2 technology subareas: chemical propulsion, non-chemical propulsion, advanced propulsion technologies, and supporting technologies. This technology area includes pro - pulsion for such diverse applications as fine pointing an astrophysics satellite in low Earth orbit (LEO), robotic science and Earth observation missions, high-thrust Earth orbit departure for crewed vehicles, low-thrust cargo transfer for human exploration, and planetary descent, landing, and ascent propulsion, and results in diverse set of technologies including traditional space-storable chemical, cryogenic chemical, various forms of electric propul- sion, various forms of nuclear propulsion, chemical and electric micropropulsion, solar sails, and space tethers.

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48 NASA SPACE TECHNOLOGY ROADMAPS AND PRIORITIES modeling, coupled stability and 6DOF (degrees of freedom) trajectory analysis, multi-disciplinary analysis tools, and other high-fidelity analysis. This technology also includes development and application of experimental validation including flight tests. This technology is widely applicable to all EDL missions and to the successful development and implementation of the other high-priority technologies in this roadmap. Technology 9.4.6, Instrumentation and Health Monitoring Complete simulation of the entry environment is impossible in ground-based test facilities. Although ground- based test facilities are indispensable in developing thermal protection systems, the complete rigorous validation of TPS design algorithms can be achieved only through comparison of predictions with flight data. Also, health monitoring instrumentation can provide system performance data as well as evidence that vehicle systems are operating properly prior to entry. This technology has wide applicability to and would improve the safety and reliability of EDL missions. Technology 9.4.4, Atmosphere and Surface Characterization The goal of this technology is to provide a description of the atmosphere and surface of a planet in suffi - cient detail to facilitate the planning and execution of planetary missions. In the case of planetary atmospheres, a predictive model is required that will define the spatial and temporal atmospheric characteristics on global, zonal, and local scales, including annual, seasonal, and daily variations. Such models exist for the Moon, Mars, and Venus, but they do not provide the needed level of detail. For other planets, the models that exist provide only gross descriptions with very little detail. Atmosphere models are of critical importance for entry missions that involve aeromaneuvering for increased landing accuracy and aerocapture to increase landed mass. Research and technology development topics of particular interest include distributed weather measurements on Mars, the development of a standard, low-impact measurement package for all Mars landed missions, the development of orbiter instruments for wind and atmospheric property characterization, and the development of higher fidelity atmospheric models. Both basic science investigations and the development of predictive engineering models are elements critical to this technology. Technology 9.4.3, Systems Integration and Analyses The design of EDL systems is a highly coupled and interdependent set of capabilities consisting of software and hardware components as well as multiple disciplines. The nature of this problem lends itself to technologies that develop improved methods of performing systems integration and analysis, such as multidisciplinary design optimization. Effective system integration and optimization involves incorporating the various disciplines involved in an EDL system while also capturing the multiple phases of flight of entry, descent, and landing. While systems integration and analyses technology is not expected to be game-changing, it is considered a high-priority technol - ogy because it supports the complete mission set, provides low risk and reasonableness, requires minimal time and effort, and is applicable to achieving all six of the EDL top technical challenges. Additional Information Facilities and continuity are two subjects that are not within the purview of the Office of the Chief Technologist but are critical to the success of EDL developments and therefore forefront to discussions by the panel and also by numerous participants in the EDL workshop and in the open survey. Therefore further comments about these elements have been included in the relevant appendix for this technology area (Appendix L). TA10 Nanotechnology The roadmap for TA10, Nanotechnology, addresses four subareas: engineered materials and structures, energy generation and storage, propulsion, and sensors, electronics, and devices. Nanotechnology describes the manipula - tion of matter and forces at the atomic and molecular levels and includes materials or devices that possess at least one dimension within a size range of 1-100 nm. At this scale, quantum mechanical forces become important in

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49 TOP TECHNICAL CHALLENGES AND HIGH-PRIORITY TECHNOLOGIES BY ROADMAP that the properties of nano-sized materials or devices can be substantially different than the properties of the same material at the macro scale. Nanotechnology can provide great enhancement in properties, and materials engineered at the nano-scale will shift the paradigm in space exploration, sensors, propulsion, and overall systems design. Before prioritizing the level 3 technologies in this technology area, several changes were made to the roadmap, which are illustrated in the relevant appendix (Appendix M). TA10 Top Technical Challenges 1. Nano-Enhanced Materials: Reduce spacecraft and launch vehicle mass through the development of lightweight and/or multifunctional materials and structures enhanced by nanotechnologies. Development of advanced materials using nanotechnologies can improve performance in numerous areas. Nano-enhanced composites have the capability to enhance mission performance by increasing the strength and stiff- ness of materials and reducing structural weight. Multi-scale models valid over nano- to macro-scales are needed to understand nano-enhanced composite materials’ failure mechanisms and interfaces. Multi-physics models are needed to address fabrication processes, operations in extreme environments, and designing with active materials. Additionally, new production methodologies are required to manufacture the raw nanomaterials and to controllably incorporate them into other materials. 2. Increased Power: Increase power for future space missions by developing higher efficiency, lower mass, and smaller energy systems using nanotechnologies. Energy generation and energy storage will remain a top technical challenge for all future space-related mis - sions. Nanotechnology can improve performance for energy generation, energy storage, and energy distribution, and it will enable sensors to be self-powered and allow for distributed sensing in a networked fashion. Newer technologies such as nano-structured metamaterials and photonic or phononic crystals with spectral compression will improve collection efficiencies and provide new capabilities. 3. Propulsion Systems: Improve launch and in-space propulsion systems by using nanotechnologies. Advances in nanotechnology will enable new propellants, potentially by providing higher combustion effi - ciency and enabling alternative fuel materials. More-energetic propellants will reduce fuel mass in solid motors and provide tailorable ignition and reaction rates. Higher-temperature and lower-erosion structural materials based on nanomaterials could reduce the weight of engine nozzles and propulsion structures. 4. Sensors and Instrumentation: Develop sensors and instrumentation with unique capabilities and better perfor- mance using nanotechnologies. The success of NASA space missions relies heavily on a variety of sensing methods and sensor technologies for numerous environments in addition to scientific data collection. Nano-sensor technology allows the incorpora - tion of sensors in structures and systems that are smaller, more energy efficient, and more sensitive, allowing for more complete and accurate health assessments. Nanotechnology also permits targeted sensor applications that improve functional efficiency and allows miniaturization of instruments with enhanced performance. 5. Thermal Management: Improve the performance of thermal management systems by using nanotechnology. Thermal management can reduce overall system cost and weight, with the direct benefit of reducing over- all launch vehicle weight. Thermal control is often required at the system level as well as at the subsystem and component level. Nanotechnology can be used to tailor the thermal conductivity of materials, making them more efficient conductors or insulators.

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50 NASA SPACE TECHNOLOGY ROADMAPS AND PRIORITIES TA10 High-Priority Technologies Technology 10.1.1, (Nano) Lightweight Materials and Structures Nano-sized materials have the promise of substantially improving the thermal, electrical, and/or mechanical properties of components and structures while reducing weight, allowing for the development of multifunctional, lightweight materials and structures that will revolutionize aerospace system design and capability. This technol - ogy is game-changing because reductions in the structural and payload weight of a space vehicle allow for higher efficiency launches with increased payload capacity, allowing NASA greater flexibility in mission design. Lack of research into fabrication methodologies related to scale will slow development of lightweight materials and structures. Additionally, strength and performance gains may not be achieved if control of nanoparticle dispersion, ordering, and interface properties is not addressed. Technology 10.2.1, (Nano) Energy Generation Nanotechnology impacts energy generation by improving the material systems of existing energy storage and generation systems. This technology is game-changing because lighter, stronger materials and structures allow for more payload devoted to energy generation and power storage, and more efficient energy generation allows for lighter payloads at launch. Technology 10.3.1, Nanopropellants Nanopropellants include the use of nano-sized materials as a component of the propellant and as gelling agents for liquid fuels. The nano-size provides a material with enormous reactive surface areas. The use of nano- sized materials as a component of the propellant can solve several problems including potentially the toxicity and environmental hazards of hypergolic and solid propellants and the handling requirements for cryogenics, while also heightening combustion efficiency and potentially impacting the controllability of ignition and reac - tion rates. The use of nanopropellants can provide a 15-40 percent increase in efficiency and potentially provide multi-functionality. Technology 10.4.1, (Nano) Sensors and Actuators Nano-scale sensors and actuators allow for improvements in sensitivity and detection capability while operat - ing at substantially lower power levels. Nanosensors are smaller, more energy efficient, and more sensitive, allowing for more complete and accurate health assessments as well as targeted sensor applications. The panel designated this as a high-priority technology because of the overall benefit offered to all missions. Additional Information Future NASA missions depend highly on advances such as lighter and stronger materials, increased reliability, and reduced manufacturing and operating costs, all of which will be impacted by the incorporation of nanotechnol - ogy. Major challenges to the broad use and incorporation of nano-engineered materials into useful products are the limited availability of certain raw nanomaterials and their variable quality. Nanotechnology is a very broad area of research and is crosscutting with and impacts every other roadmap. Furthermore, recognizing that much work sponsored by NSF and other agencies on a national R&D effort in nanotechnology is underway in government labs, universities, and industry, the NASA research for space applications should be well coordinated with this national effort. Nanotechnology research at NASA does not seem to be centrally coordinated, and thus the potential exists for substantial duplication of effort. The panel suggests that there be substantial coordination among the nanotech - nology researchers at the various NASA centers, the national R&D effort, and specific NASA mission end users. TA11 Modeling, Simulation, and Information Technology and Processing The roadmap for TA11 consists of four technology subareas, including computing, modeling, simulation, and information processing. NASA’s ability to make engineering breakthroughs and scientific discoveries is limited not

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51 TOP TECHNICAL CHALLENGES AND HIGH-PRIORITY TECHNOLOGIES BY ROADMAP only by human, robotic, and remotely sensed observation, but also by the ability to transport data and transform the data into scientific and engineering knowledge to meet sophisticated needs. With data volumes exponentially increasing into the petabyte and exabyte ranges, modeling, simulation, and information technology and processing requirements demand advanced supercomputing capabilities. Before prioritizing the level 3 technologies of TA11, 11.2.4, Science and Engineering Modeling, was divided into two parts: 11.2.4a, Science Modeling and Simulation, and 11.2.4b, Aerospace Engineering Modeling and Simulation. TA11 Top Technical Challenges 1. Flight-Capable Devices and Software: Develop advanced flight-capable devices and system software for flight computing. Space applications require devices that are immune to, or at least tolerant of, radiation-induced effects, within tightly constrained resources of mass and power. The software design that runs on these advanced devices also requires new approaches. The critical and complex software needed for these demanding applications requires further development to manage this complexity at low risk. 2. New Software Tools: Develop new flight and ground computing software tools to take advantage of new comput- ing technologies by keeping pace with computing hardware evolution, eliminating the multi-core “programmability gap,” and permitting the porting of legacy codes. Since about 2004, the increase in computer power has come about because of increases in the number of cores per chip and use of very fast vector graphical processor units rather than increases in processor speed. NASA has not yet addressed the challenge of developing efficient codes for these new computer architectures. NASA’s vast inventory of legacy engineering and scientific codes will need to be re-engineered to make effective use of rapidly changing advanced computational systems. 3. Testing: Improve the reliability and effectiveness of hardware and software testing and enhance mission robust - ness via new generations of affordable simulation software tools. New software tools that allow insight into the design of complex systems will support the development of systems with well understood, predictable behavior while minimizing or eliminating undesirable responses. 4. Simulation Tools: Develop scientific simulation and modeling software tools to fully utilize the capabilities of new generations of scientific computers. Supercomputers have become increasingly powerful, often enabling realistic multi-resolution simulations of complex astrophysical, geophysical, and aerodynamic phenomena, including the evolution of circumstellar disks into planetary systems, the formation of stars in giant molecular clouds in galaxies, and the evolution of entire galaxies, including the feedback from supernovas and supermassive black holes. However, efficient new codes that use the full capabilities of these new computer architectures are still under development. TA11 High-Priority Technologies Technology 11.1.1, Flight Computing Low-power, radiation-hardened, high-performance processors will continue to be in demand for general application in the space community. Processors with the desired performance are readily available for terrestrial applications; however, radiation-hardened versions of these are not. A major concern is ensuring the continued availability of radiation-hardened integrated circuits for space. Action may be required if NASA and other govern - ment organizations wish to maintain domestic sources for these devices, or a technology development effort may

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52 NASA SPACE TECHNOLOGY ROADMAPS AND PRIORITIES be required to determine how to apply commercial devices in the space environment. This technology can have significant impact because multi-core/accelerated flight processors can yield major performance improvements in on-board computing throughput, fault management, and intelligent decision making and science data acquisi - tion, and will enable autonomous landing and hazard avoidance. Its use is anticipated across all classes of NASA missions. Technology 11.1.2, Ground Computing Ground computing technology consists of programmability for multi-core/hybrid/accelerated computer archi - tectures, including developing tools to help port existing codes to these new architectures. The vast library of legacy engineering and scientific codes does not run efficiently on the new computer architectures in use, and technology development is needed to create software tools to help programmers convert legacy codes and new algorithms so that they run efficiently on these new computer systems. Continuous technology improvements will be required as computer system architectures steadily change. Technology 11.2.4a, Science Modeling and Simulation This technology consists of multi-scale modeling, which is required to deal with complex astrophysical and geophysical systems with a wide range of length scales or other physical variables. Better methods also need to be developed to compare simulations with observations in order to improve physical understanding of the impli - cations of rapidly growing NASA data sets. This technology can have significant impact because it optimizes the value of observations by elucidating the physical principles involved, and could impact many NASA missions. Technology 11.3.1, Distributed Simulation Distributed simulation technologies create the ability to share simulations between software developers, sci - entists, and data analysts. There is a need for large-scale, shared, secure, distributed environments with sufficient interconnect bandwidth and display capabilities to enable distributed analysis and visualization of observations and complex simulations. This technology could provide major efficiency improvements supporting collaborations, particularly interdisciplinary studies that would benefit numerous NASA missions in multiple areas. TA12: Materials, Structures, Mechanical Systems, and Manufacturing The TA12 portfolio is extremely broad, including five technology areas: materials, structures, mechanical systems, manufacturing, and crosscutting technologies. TA12 consists of enabling core disciplines and encom - passes fundamental new capabilities that directly impact the increasingly stringent demands of NASA science and exploration missions. NASA identified human radiation protection and reliability technologies as two critical areas upon which the technologies in TA12 should be focused. TA12 Top Technical Challenges 1. Multifunctional Structures: Conceive and develop multifunctional structures, including shielding, to enable new mission capabilities such as long-duration human spaceflight and to reduce mass. Structures carry load and maintain shape. To the extent that a structure can simultaneously perform additional functions, mission capability can be increased with decreased mass. Such multifunctional materials and structures will require new design analysis tools and might exhibit new failure modes; these should be understood for use in systems design and space systems operations. 2. Reduced Mass: Reduce the mass of launch vehicle, spacecraft, and propulsion structures to increase payload mass fraction, improve mission performance, and reduce cost.

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53 TOP TECHNICAL CHALLENGES AND HIGH-PRIORITY TECHNOLOGIES BY ROADMAP Lightweight materials and structures are required to enhance mission performance and enable new mission opportunities. Advanced composites, revolutionary structural concepts, more energetic propellants, and materials with higher temperature tolerance and lower erosion potential represent some of the possible strategies to reducing mass. 3. Computational Modeling: Advance new validated computational design, analysis, and simulation methods for materials and structural design, certification, and reliability. First-principle physics models offer the game-changing potential to guide tailored computational materials design. A validated computational modeling methodology could provide the basis for certification by analysis, with experimental evidence, as available, used to verify and improve confidence in the suitability of a design. 4. Large-Aperture Systems: Develop reliable mechanisms and structures for large-aperture systems. These must be stowed compactly for launch, yet achieve high-precision final shapes. Numerous NASA missions employ mechanical systems and structures that must deploy reliably in extreme environments, often to achieve a desired shape with high precision. These can be deployed, assembled, or manu - factured in space and may involve flexible materials. Modularity and scalability are desirable features of such concepts and may require development of autonomous adaptive control systems and technology to address critical functional elements and materials. 5. Structural Health Monitoring: Enable structural health monitoring and sustainability for long-duration mis - sions, including integration of unobtrusive sensors and responsive on-board systems. Mission assurance would be enhanced by an integrated structural health monitoring system that could detect and assess the criticality of in-service damage or fault, and then define an amelioration process or trigger a repair in self-healing structures. An autonomous integrated on-board systems capability would be game-changing for long-duration, remote missions. 6. Manufacturing: Enable cost-effective manufacturing for reliable high-performance structures and mechanisms made in low-unit production, including in-space manufacturing. Advanced NASA space missions need affordable structures, electronics systems, and optical payloads, requir - ing advances in manufacturing technologies. In-space manufacturing offers the potential for game-changing weight savings and new mission opportunities. TA12 High-Priority Technologies Nine high-priority technologies were identified in TA12, some of which connected directly to other technolo - gies in TA12 and to other technology roadmaps in support of a common technical challenge. Technology 12.2.5, Innovative, Multifunctional Concepts (Structures) Structures that perform functions in addition to carrying load and maintaining shape can increase mission capability while decreasing mass and volume. Multifunctional structural concepts involve increasing levels of system integration and provide a foundation for increased autonomy. Examples of multifunctional structural concepts include habitat structures with integral shielding to reduce radiation exposure and micrometeoroid and orbital debris risk for long-duration human spaceflight missions. The human spaceflight applications of multifunc - tional structures technology are unique to NASA and dictate that NASA lead associated technology development. Other multifunctional structures concepts, such as those involving thermal-structural and electrical-structural

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54 NASA SPACE TECHNOLOGY ROADMAPS AND PRIORITIES functionality, are likely to find broader applications. Therefore NASA would benefit from partnerships in the development of these technology concepts. Technology 12.2.1, Lightweight Concepts (Structures) Lightweight structural concepts could significantly enhance future exploration and science missions and enable new missions. For example, lightweight cryo-tank concepts could improve launch vehicle performance and enable on-orbit fuel storage depots, and lightweight concepts for deployable solar sails, precision space structures, and inflatable, deployable heat shields could provide opportunities for new missions or significantly benefit planned science missions. Lightweight structural concepts developed by NASA and the aerospace industry have found extensive applications in transportation, commercial aircraft, and military systems. Technology 12.1.1, Lightweight Structure (Materials) Advanced composite, metallic, and ceramic materials, as well as cost-effective processing and manufacturing methods, are required to develop lightweight structures for future space systems. Lightweight structural materials developed by NASA and other government agencies, academia, and the aerospace industry have found extensive applications in transportation, commercial aircraft, and military systems. Continued NASA leadership in materi - als development for space applications could result in new materials systems with significant benefits in weight reduction and cost savings. This technology has the potential to significantly reduce the mass of virtually all launch vehicles and payloads, creating opportunities for new missions, improved performance, and reduced cost. Technology 12.2.2, Design and Certification Methods (Structures) Current structural certification approaches rely on a conservative combination of statistics-based material quali- fication and experience-based load factors and factors of safety, followed by design development and qualification testing. Verification testing and mission history indicate that structures tend to be over-designed and thus heavier than necessary. A model-based virtual design certification methodology could be developed to design and certify space structures more cost-effectively. This technology provides another path to lighter and more affordable space structures while assuring adequate reliability, and is applicable to all NASA space vehicles including uncrewed, robotic, and human-rated vehicles for use in science missions, and human exploration over extended periods of time. Technology 12.5.1, Nondestructive Evaluation and Sensors (Crosscutting) Non-destructive evaluation (NDE) has evolved from its early uses for quality control product acceptance, and periodic inspection to include continuous health monitoring and autonomous inspection. Early detection, localization, and mitigation of critical conditions will enhance mission safety and reliability. NASA has proposed an integrated NDE and sensor technology capability in a virtual digital flight leader (VDFL) that would include a digital representation of a vehicle with real-time assessment of vehicle structural health to predict performance and identify operational actions necessary to address vehicle performance. NDE and sensor technologies are likely to impact multiple areas and multiple missions, especially as mission durations continue to increase. Technology 12.3.4, Design and Analysis Tools and Methods (Mechanical Systems) High-fidelity kinematics and dynamics design and analysis tools and methods are essential for modeling, designing, and certifying advanced space structures and mechanical systems. A mechanism interrelation/correlation analysis methodology would enable creation of a single model of spacecraft mechanical systems and would reduce the stack-up of margins across disciplines. Such models could be integrated into a health-management system for diagnosis, prognosis, and performance assessment and in a VDFL system. This technology is applicable to all NASA space vehicles including uncrewed, robotic, and human-rated vehicles for use in science missions, and human exploration over extended periods of time.

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55 TOP TECHNICAL CHALLENGES AND HIGH-PRIORITY TECHNOLOGIES BY ROADMAP Technology 12.3.1, Deployables, Docking and Interfaces (Mechanical Systems) Many future science missions involving imaging and scientific data collection will benefit from the combina - tion of a large aperture and precision geometry, the achievement of which will most likely involve deployment, possibly including flexible materials or other approaches such as assembly or in-space manufacturing. Docking and the associated interfaces provide another approach to building up larger platforms from smaller ones. These mechanical systems and structures must deploy reliably in extreme environments and achieve a desired shape with high precision; some systems may require the use of a control system to maintain a precise shape under opera - tional disturbances. Large precise aperture systems are critical to some NASA science missions as well as some DOD surveillance missions, enabling advanced mission performance. This suggests that NASA lead associated technology development, finding partners when feasible. Space missions have not infrequently failed as the result of failure of a separation, release, or deployment system, and clearly technology development to pursue improve - ments in the reliability of such systems is needed. Technology 12.3.5, Reliability/Life Assessment/Health Monitoring (Mechanical Systems) In recent experience, the reliability of mechanical systems has been a more significant contributor to the failure of space missions than the reliability of structures designed to meet current certification standards. An integrated sensor system would provide a basis for determining the current state of a mechanical system, as well as prediction of future behavior. To be most effective in assuring mission reliability, the ability to take corrective action must also be designed into the system. This technology is closely linked with the area of deployables, docking, and interfaces, and could enable a dramatic increase in the reliability of mechanical systems and structures, especially for long-duration space missions. Technology 12.4.2, Intelligent Integrated Manufacturing and Cyber Physical Systems (Manufacturing) The fielding of high-performance materials, structures, and mechanisms for space applications requires specialized manufacturing capabilities. Through advances in technology, particularly IT-based, more general but flexible manufacturing methods can be adapted to produce specialized components and systems. There are existing industrial capabilities in such technologies, and investments in similar technologies from the Air Force Research Laboratory have contributed significantly and are expected to continue because of the potential impacts on affordability. Manufacturing is an area in which NASA can benefit from monitoring developments in hardware, software, and supply chain management, and there is potential to form government, university, and industry con - sortia to pursue these ends. This technology would enable physical components to be manufactured in space, on long-duration human missions if necessary. This could reduce the mass that must be carried into space for some exploration missions, and furthermore this technology promises improved affordability of one-off structures made from high-performance materials. This technology is applicable to all NASA space vehicles including uncrewed, robotic, and human-rated vehicles for use in science missions, and human exploration over extended periods of time. Additional Comments Perhaps as a result of the need to address such a broad range of technologies in a summary document, the TA12 roadmap devotes little space to discussion of the assumed mission model, or to the inter-dependence of technology development, and to some degree can be read as a catalog of technology items as much as a plan. Detailed interpretation of TA12 is left to the reader, making it challenging to suggest specific modifications to the schedule. Additionally, the TA12 roadmap addresses neither improved understanding of the intense vibroacoustic envi - ronment of launch nor novel approaches that could reduce structural dynamic response, which frequently drive the structural design of spacecraft.

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56 NASA SPACE TECHNOLOGY ROADMAPS AND PRIORITIES TA13 Ground and Launch Systems Processing The goal of TA13 is to provide a flexible and sustainable U.S. capability for ground processing as well as launch, mission, and recovery operations to significantly increase safe access to space. The TA13 roadmap con - sists of four technology subareas, including technologies to optimize the operational life-cycle, environmental and green technologies, technologies to increase reliability and mission availability, and technologies to improve mission safety/mission risk. The primary benefit derived from advances in this technology area is reduced cost, freeing funds for other investments. Before prioritizing the technologies of TA13, the panel considered the TA13 breakdown structure but did not recommend any changes. TA13 Top Technical Challenges Although advanced technology can contribute to solving the major challenges of advances in ground and launch systems (for example, cost and safety concerns), they are most effectively addressed through improvements in management practices, engineering, and design. Therefore the panel did not identify any technical challenges related to TA13 on the level of those associated with the other roadmaps. TA13 High-Priority Technologies The panel did not identify any high-priority level 3 technologies for TA13. Additional Information The panel does not have any recommendations with regard to development and schedule changes. TA14 Thermal Management Systems Thermal management systems are systems and technologies that are capable of handling high thermal loads with excellent temperature control, with a goal of decreasing the mass of existing systems. The roadmap for TA14, Thermal Management Systems, consists of three technology subareas: cryogenic systems, thermal control systems, and thermal protection systems. Before prioritizing the technologies of TA14, the panel considered the TA14 breakdown structure but did not recommend any changes. TA14 Top Technical Challenges 1. Thermal Protection Systems: Develop a range of rigid ablative and inflatable/flexible/deployable thermal protection systems (TPS) for both human and robotic advanced high-velocity return missions, either novel or reconstituted legacy systems. TPS is mission-critical for all future human and robotic missions that require planetary entry or reentry. The current availability of high-TRL rigid ablative TPS is adequate for LEO re-entry but is inadequate for high-energy re-entries to Earth or planetary missions. Ablative materials are enabling for all NASA, military, and commercial missions that require high-mach-number re-entry, such as near-Earth asteroid visits and Mars missions, whether human or robotic. 2. Zero Boil-Off Storage: Accelerate research on advanced active and passive systems to approach near-zero boil-off in long-term cryogenic storage. Long-term missions that require cryogenic life-support supplies, cryogenic propellants, or very low tempera - ture for scientific instrument support will require near-zero boil-off rates. Multiple technologies in TA14 support

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57 TOP TECHNICAL CHALLENGES AND HIGH-PRIORITY TECHNOLOGIES BY ROADMAP this, and emphasis should be placed on reliable, repairable, supportable active and passive systems that can be integrated into many missions. 3. Radiators: Develop improved space radiators with reduced mass. Radiators are used for energy removal from spacecraft and planetary base systems and are mission-critical for many proposed missions. To reduce radiator mass, area, and pumping power, research is needed on variable emissivity, very low absorptivity-to-emissivity ratio, self-cleaning, and high-temperature coatings, as well as on lightweight radiators or compact storage systems for extending extravehicular activity capability. 4. Multifunctional Materials: Develop high-temperature multifunctional materials that combine structural strength, good insulating ability, and possibly other functions. Multifunctional systems can provide significant mass savings, allowing increased payload weight. Multi- functional TPS and multi-layer insulation (MLI) systems that combine thermal, structural, or micrometeoroid and orbital debris (MMOD) and crew radiation protection could provide significant weight savings and enable long- duration missions, and can also be used for planetary habitat thermal and multifunctional protection. 5. Verification and Validation: Develop, verify, validate, and quantify uncertainty analysis requirements for new or improved comprehensive computer codes for thermal analysis. Upgrades to predictive codes for ablation during re-entry heating are needed to include closely coupled multi-phase ablation and radiative heating into the flow simulations, with careful attention given to verification, validation, and uncertainty quantification. 6. Repair Capability: Develop in-space thermal protection system repair capability. Repair capability is especially important for long-duration missions. TPS repair developed for Space Shuttle Orbiter TPS should be continued and expanded to provide a repair method for future spacecraft. 7. Thermal Sensors: Enhance thermal sensor systems and measurement technologies. Operational instrumentation is necessary to understand anomalies, material or performance degradation and performance enhancements, and advanced science mission measurements. TA14 High-Priority Technologies Technology 14.3.1, Ascent/Entry TPS Effective heat shields and thermal insulation during ascent and atmospheric entry are mission-critical for all robotic and human missions that require entry into a planetary atmosphere. Ascent/entry TPS is game-changing because it is necessary for every planetary atmospheric ascent and/or entry mission, including every mission for return to Earth. Particularly critical level 4 technology items are rigid ablative TPS, obsolescence-driven TPS materials and process development, multi-functional TPS, and flexible TPS. Technology 14.1.2, Active Thermal Control of Cryogenic Systems Low to zero boil-off of cryogenic fluids will be mission-critical for long-duration missions, and cannot be achieved with present technology. A goal of this technology is to develop an overall cryogenic system design that integrates active and passive technologies into an optimal system, as well as instrumentation and sensors to monitor fluid mass. Minimization of active system capacity through effective use of passive control should help increase overall system reliability. This technology can enable a wide variety of long-duration missions.

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58 NASA SPACE TECHNOLOGY ROADMAPS AND PRIORITIES Additional Information Software validation and the use of ground test facilities are two overarching crosscutting issues pertinent to TA14 that are addressed in detail in Chapter 4. NASA recognizes that budgetary and staffing constraints make it impossible to carry out all of the tasks proposed in the roadmap. It will be necessary to coordinate and cooperate with other organizations for funding research and portions of these technologies. Many of the tasks could be combined; for example, the draft roadmap breaks Technology 14.1.1 Passive Thermal Control into eight items, all of which deal with minimizing heat leaks, and the research should be attacked as an overall system rather than technology by technology. REFERENCES NRC (National Research Council). 2003. The Sun to the Earth—and Beyond: A Decadal Research Strategy in Solar and Space Physics. The National Academies Press, Washington, D.C. NRC. 2007. Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond. The National Academies Press, Washington, D.C. NRC. 2010. New Worlds, New Horizons in Astronomy and Astrophysics. The National Academies Press, Washington, D.C. NRC. 2011. Vision and Voyages for Planetary Science in the Decade 2013-2022. The National Academies Press, Washington, D.C.