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.
1The draft space technology roadmaps are available at http://www.nasa.gov/offices/oct/strategic_integration/technology_roadmap.html.
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.
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 technology 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 expertise, 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.
The steering committee identified three main criteria on which the technologies were to be judged for evaluation. 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
TABLE 2.1 NASA Technology Readiness Levels
|TRL||Definition||Hardware Description||Software Description||Exit Criteria|
|1. Basic principles observed and reported.||Lowest level of technology readiness. Scientific research begins to be translated into applied research and development. Examples might include paper studies of a technology’s basic properties.||Scientific knowledge generated underpinning hardware technology concepts/applications.||Scientific knowledge generated underpinning basic properties of software architecture and mathematical formulation.||Peer reviewed publication of research underlying the proposed concept/application.|
|2. Technology concept and/or application formulated.||Invention begins. Once basic principles are observed, practical applications can be invented. The application is speculative, and there is no proof or detailed analysis to support the assumption. Examples are still limited to paper studies.||Invention begins, practical application is identified but is speculative, no experimental proof or detailed analysis is available to support the conjecture.||Practical application is identified but is speculative, no experimental proof or detailed analysis is available to support the conjecture. Basic properties of algorithms, representations and concepts defined. Basic principles coded. Experiments performed with synthetic data.||Documented description of the application/concept that addresses feasibility and benefit.|
|3. Analytical and experimental critical function and/or characteristic proof of concept.||At this step in the maturation process, active research and development (R&D) is initiated. This must include both analytical studies to set the technology into an appropriate context and laboratory-based studies to physically validate that the analytical predictions are correct. These studies and experiments should constitute “proof-of-concept” validation of the applications/concepts formulated at TRL 2.||Analytical studies place the technology in an appropriate context and laboratory demonstrations, modeling and simulation validate analytical prediction.||Development of limited functionality to validate critical properties and predictions using non-integrated software components.||Documented analytical/experimental results validating predictions of key parameters.|
|4. Component and/or breadboard validation in laboratory environment.||Following successful “proof-of-concept” work, basic technological elements must be integrated to establish that the pieces will work together to achieve concept-enabling levels of performance for a component and/or breadboard. This validation must be devised to support the concept that was formulated earlier and should also be consistent with the 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.||A low fidelity system/component breadboard is built and operated to demonstrate basic functionality and critical test environments, and associated performance predictions are defined relative to the final operating environment.||Key, functionally critical software components are integrated, and functionally validated, to establish interoperability and begin architecture development. Relevant environments defined and performance in this environment predicted.||Documented test performance demonstrating agreement with analytical predictions. Documented definition of relevant environment.|
|TRL||Definition||Hardware Description||Software Description||Exit Criteria|
|5. Component and/or breadboard validation in relevant environment.||At this level, the fidelity of the component and/or breadboard being tested has to increase significantly. The basic technological elements must be integrated with reasonably realistic supporting elements so that the total applications (component-level, subsystem-level, or system-level) can be tested in a “simulated” or somewhat realistic environment.||A medium fidelity system/component brassboard is built and operated to demonstrate overall performance in a simulated operational environment with realistic support elements that demonstrates overall performance in critical areas. Performance predictions are made for subsequent development phases.||End-to-end software elements implemented and interfaced with existing systems/simulations conforming to target environment. End-to-end software system, tested in relevant environment, meeting predicted performance. Operational environment performance predicted. Prototype implementations developed.||Documented test performance demonstrating agreement with analytical predictions. Documented definition of scaling requirements.|
|6. System/subsystem model or prototype demonstration in a relevant environment.||A major step in the level of fidelity of the technology demonstration follows the completion of TRL 5. At TRL 6, a representative model or prototype system or system, which would go well beyond ad hoc, “patch-cord,” or discrete component level breadboarding, would be tested in a relevant environment. At this level, if the only relevant environment is the environment of space, then the model or prototype must be demonstrated in space.||A high fidelity system/component prototype that adequately addresses all critical scaling issues is built and operated in a relevant environment to demonstrate operations under critical environmental conditions.||Prototype implementations of the software demonstrated on full-scale realistic problems. Partially integrate with existing hardware/software systems. Limited documentation available. Engineering feasibility fully demonstrated.||Documented test performance demonstrating agreement with analytical predictions.|
|7. System prototype demonstration in an operational environment.||Prototype near or at planned operational system. TRL 7 is a significant step beyond TRL 6, requiring an actual system prototype demonstration in a space environment. The prototype should be near or at the scale of the planned operational system, and the demonstration must take place in space. Examples include testing the prototype in a test bed.||A high fidelity engineering unit that adequately addresses all critical scaling issues is built and operated in a relevant environment to demonstrate performance in the actual operational environment and platform (ground, airborne, or space).||Prototype software exists having all key functionality available for demonstration and test. Well integrated with operational hardware/software systems demonstrating operational feasibility. Most software bugs removed. Limited documentation available.||Documented test performance demonstrating agreement with analytical predictions.|
|TRL||Definition||Hardware Description||Software Description||Exit Criteria|
|8. Actual system competed and “flight qualified” through test and demonstration.||Technology has been proven to work in its final form and under expected conditions. In almost all cases, this level is the end of true system development for most technology elements. This might include integration of new technology into an existing system.||The final product in its final configuration is successfully demonstrated through test and analysis for its intended operational environment and platform (ground, airborne, or space).||All software has been thoroughly debugged and fully integrated with all operational hardware and software systems. All user documentation, training documentation, and maintenance documentation completed. All functionality successfully demonstrated in simulated operational scenarios. Verification and Validation (V&V) completed.||Documented test performance verifying analytical predictions.|
|9. Actual system flight proven through successful mission operations||Actual application of the technology in its final form and under mission conditions, such as those encountered in operational test and evaluation. In almost all cases, this is the end of the last “bug fixing” aspects of true system development. This TRL does not include planned product improvement of ongoing or reusable systems.||The final product is successfully operated in an actual mission.||All software has been thoroughly debugged and fully integrated with all operational hardware/software systems. All documentation has been completed. Sustaining software engineering support is in place. System has been successfully operated in the operational environment.||Documented mission operational results.|
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
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 criterion. 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-a-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
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 timeframe 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 proceeding 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 specifically 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 50people) 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
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
TABLE 2.2 Numerical Weighting Factors Given to Evaluation Criteria in Panel Assessments
Alignment with NASA needs
Alignment with non-NASA aerospace needs
Alignment with non-aerospace national goals
|Technical risk and challenge (18)|
Technical risk and reasonableness
Sequencing and timing
Time and effort
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 x 27 + 3 x 5 + 3 x 2 + 0 x 2 + 3 x 10 – 1 x 4 – 1 x 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
2The 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 relative 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.
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.
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 workshops 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.
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.
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 Technology, Pasadena, CA||Panel 1: Propulsion and Power|
|TA02 In-Space Propulsion Technologies||March 21, 2011||California Institute of Technology, Pasadena, CA||Panel 1: Propulsion and Power|
|TA03 Space Power and Energy Storage||March 24, 2011||California Institute of Technology, Pasadena, CA||Panel 1: Propulsion and Power|
|TA04 Robotics, TeleRobotics, and Autonomous Systems||March 30, 2011||Keck Center, Washington, DC||Panel 2: Robotics, 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 Habitation Systems||April 26, 2011||The Lunar and Planetary Institute, Houston, TX||Panel 4: Human Health and Surface Exploration|
|TA07 Human Exploration Destination Systems||April 27, 2011||The Lunar and Planetary Institute, Houston, TX||Panel 4: Human Health and Surface Exploration|
|TA08 Science Instruments, Observatories, and Sensor Systems||March 29, 2011||Beckman Center, Irvine, CA||Panel 3: Instruments and 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 Technology and Processing||May 10, 2011||Keck Center, Washington, DC||Panel 3: Instruments and Computing|
|TA12 Materials, Structures, Mechanical Systems, and Manufacturing||March 10, 2011||Keck Center, Washington, DC||Panel 5: Materials|
|TA13 Ground and Launch Systems Processing||March 24, 2011||California Institute of Technology, Pasadena, CA||Panel 1: Propulsion and 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 effecting cost is a major technical challenge.
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.
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 economics, 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 propulsion 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 propulsion, various forms of nuclear propulsion, chemical and electric micropropulsion, solar sails, and space tethers.
Before prioritizing the technologies in TA02, several technologies were renamed, deleted, or moved. The steering committee deleted 2.4.1 Engine Health Monitoring and Safety, 2.4.3 Materials and Manufacturing Technologies, 2.4.4 Heat Rejection, and 2.4.5 Power, because these technologies did not fall under the scope of TA02. In each case, the reader is referred to other sections of the roadmap (2.4.1 to TA04, 2.4.3 to TA12, 2.4.4 to TA14, and 2.4.5 to TA03) to learn the details of what should be done in these areas.
TA02 Top Technical Challenges
1. High-Power Electric Propulsion Systems: Develop high-power electric propulsion systems technologies to enable high ΔV missions with heavy payloads.
Electric propulsion systems have a higher propellant efficiency than other in-space propulsion technologies that will be available in the foreseeable future, with applications to all NASA, DOD, and commercial space mission areas. Development of high power electric propulsion systems will enable larger scale missions with heavy payloads, and demonstration of large scale electric propulsion vehicles is required to ensure adequate control during autonomous rendezvous and docking operations necessary for either cargo or small body proximity operations.
2. Cryogenic Storage and Transfer: Enable long-term storage and transfer of cryogens in space and reliable cryogenic engine operation after long dormant periods in space.
Deep-space exploration missions will require high performance propulsion for all mission phases, including Earth departure, destination arrival, destination departure, and Earth return, occurring over the entire mission duration. Both high-thrust propulsion options, LOX/H2 chemical and LH2 nuclear thermal rockets, will require storage of cryogens for well over a year to support all mission phases, and the engines must also operate reliably after being dormant for the same period. This technical challenge must be overcome if humans are ever to explore destinations beyond the Moon.
3. Microsatellites: Develop high performance propulsion technologies for high-mobility microsatellites (<100 kg).
The broader impact of small satellites is hindered by the lack of propulsion systems with performance levels similar to those utilized in larger satellites. Most existing propulsion systems are not amenable for miniaturization and work is needed to develop concepts that scale and perform favorably. Miniature propulsion would also provide functionality in different applications, such as controlling large flexible structures. Many of these high performance propulsion technologies are near a tipping point, and moderate investment would be required to validate their applicability to small satellites.
4. Rapid Crew Transit: Establish propulsion capability for rapid crew transit to/from Mars.
Developing high performance, high thrust propulsion systems to reduce transit times for crewed missions will mitigate concerns about impacts to crew health from radiation, exposure to reduced gravity, and other effects of long-duration deep-space travel. Two realistic high-thrust options exist that could be available for missions in the next 20 years: LOX/H2 and nuclear thermal rockets. The engines must be capable of multiple restarts following prolonged periods of inactivity and must be extremely high reliability systems. There are currently no engines of either type that meet the requirements of performance, reliability, and re-start capability.
TA02 High-Priority Technologies
Technology 2.2.1, Electric Propulsion
Electric propulsion (EP) uses electrical power produced on the spacecraft to accelerate propellant to extremely high speeds. Solar electric propulsion (SEP), including arcjet, Hall thruster, and ion thruster systems, is routinely
used today for spacecraft maneuvers. Modern laboratory-model ion thrusters and Hall thrusters have been demonstrated on the ground and flight versions of these thrusters may be developed in the mid-term timeframe. Further in the future, multi-MW systems enabled by nuclear power systems could use flight versions of various thrusters currently in early laboratory testing. The development of high-power SEP systems (~100 kW to ~1 MW) could enable larger-scale or faster missions, more efficient in-space transportation systems in Earth orbit, more affordable sample return missions, and pre-positioning of cargo and ISRU facilities for human exploration missions.
Technology 2.4.2, Propellant Storage and Transfer
Propellant Storage and Transfer in space includes both the long-term storage of cryogens and the transfer of these fluids between refueling stations and the propulsion systems on spacecraft, upper stages, and Moon/Mars landing and ascent vehicles. This technology has only been validated at the component level for cryogenic fluids in laboratory environments, although “storable” propellant storage and transfer has been demonstrated in space. Propellant storage and transfer is a game-changing technology for a wide range of applications because it enables long-duration, high-thrust, high-ΔV missions for large payloads and crew and can be implemented within the next three decades.
Technology 2.2.3, (Nuclear) Thermal Propulsion
The technology includes both solar and nuclear thermal sources that heat hydrogen propellant to achieve high specific impulse. Of these two, only nuclear thermal propulsion is rated as a high-priority technology. Nuclear thermal rockets (NTRs) are high-thrust propulsion systems with the potential for twice the specific impulse of the best liquid hydrogen/oxygen chemical rockets. Critical NTR technologies include the nuclear fuel, reactor and system controls, and long-life hydrogen pumps, and technology development will also require advances in ground test capabilities, as the open-air approach previously used is no longer environmentally acceptable.
Technology 2.1.7, Micro-propulsion
Micro-propulsion technology addresses all propulsion, chemical and non-chemical, that fulfills the needs for high mobility micro-satellites (<100 kg) and extremely fine pointing and positioning for certain astrophysics missions. Small satellites, either individually or flying in formation, are being considered for increasingly complex missions, driven by low costs, fast development times, and the potential to perform tasks previously limited to large systems. Many technologies have been proposed, including miniaturization of existing systems and innovative concepts, and several promising technologies have emerged. Micro-propulsion technology development properly includes a broad range of technologies, current and future applications, and NASA, DOD, and commercial users.
In an unconstrained funding environment, the TA02 roadmap presents a reasonable approach, particularly when focus is placed on the high-priority technologies listed above. However, in a constrained funding environment it is unlikely that all the level 3 technologies shown on the schedule will be affordable.
The planetary decadal survey identifies Mars ascent propulsion and precision landing as key capabilities. (NRC, 2011, p. 311) Current entry, descent, and landing technologies are near their limits for the martian atmosphere, and some improvements in propulsion systems for descent and landing will be required. While new engineering developments are certainly required, the propulsion challenges are more in system implementation than technology development.
TA03 Space Power and Energy Storage
TA03 is divided into four technology areas: power generation, energy storage, power management and distribution, and crosscutting technologies. NASA has many unique needs for space power and energy storage technologies that require special technology solutions due to extreme environmental conditions. These missions would all benefit from advanced technologies that provide more robust power systems with lower mass.
Before prioritizing the technologies included in TA03, several were renamed, deleted, or moved, and two additional approaches to energy storage were added: (1) electric and magnetic field storage and (2) thermal storage.
TA03 Top Technical Challenges
1. Power Availability: Eliminate the constraint of power availability in planning and executing NASA missions.
Power is a critical limitation for space science and exploration and the availability of more power opens up new paradigms for how NASA operates and what can be accomplished. For example, increased power availability for human exploration missions can support more astronauts at larger outposts with more capabilities, and for robotic science missions, power availability can determine the scope and duration of the mission.
2. High Power for Electric Propulsion: Provide enabling power system technologies for high power electric propulsion for large payloads and planetary surfaces.
Advances in solar and nuclear technologies during the last decade offer the potential of developing power generation systems that can deliver tens to hundreds of kilowatts. Various designs have been utilized to enhance power efficiency, using proven fuels, power conversion technologies, and reactor materials to reduce the development and operations risk to acceptable levels. Other aspects of fission systems require technology development including heat exchangers, fluid management, scaling of power conversion devices, heat rejection components, radiation shielding, and aspects of system integration and testing.
3. Reduced Mass: Reduce the mass and stowed launch volume of space power systems.
Power systems typically constitute one third of the mass of a spacecraft at launch, and the volume available in the launch vehicle fairing can limit the size of solar arrays that can be packaged on the vehicle. Further development of new power generation, energy storage, and power delivery technologies can potentially reduce the mass and volume of these systems, enabling missions to include more science instruments, use smaller and less expensive launch vehicles, and/or provide higher power levels.
4. Power System Options: Provide reliable power system options to survive the wide range of environments unique to NASA missions.
NASA missions require power systems and components to survive many different types of extreme environments. Technology developments to meet these challenges will enable NASA to plan and execute a wide array of missions.
TA03 High-Priority Technologies
Technology 3.1.3, Solar Power Generation (Photovoltaic and Thermal)
Photovoltaic (PV) space power systems have been the workhorse of NASA science missions as well as the foundation for commercial and military systems. Solar cells directly convert sunlight into electricity, and today’s solar cells operate with 30 percent efficiency. Current emphasis is on the development of high efficiency cells as well as cells that can effectively operate in extreme environments. Nearly all spacecraft flown to date have been powered by solar arrays, and NASA has a vital interest in photovoltaic power system developments for higher power electric propulsion missions. Of particular interest are advanced array technologies that offer high specific mass and high power density. Solar power generation applies to all NASA mission areas plus DOD, as well as commercial and other civil or national applications.
Technology 3.1.5, Fission Power Generation
Space fission power systems use heat generated by fission of a nuclear fuel to power a thermal to electric conversion device to generate electric power. Key subsystems include the reactor, heat exchanger, power converter, heat rejection, and radiation shield. Space fission power systems would overcome mission infrastructure limitations associated with low power level availability, and can potentially provide a power rich environment to planetary surface exploration missions and enable high power electric propulsion systems for deep-space exploration and science missions.
Technology 3.3.3, Power Distribution and Transmission
As science and human exploration missions of the future are examined, the need for significant increases in electrical power on spacecraft becomes a clearer and higher priority. With these higher power levels, an extrapolation of the current technologies for the distribution and transmission (D&T) of power would result in unacceptably high mass and complexity; therefore more efficient D&T methods are considered high-priority. Proposed research would increase the D&T voltage, develop high frequency alternating current distribution options for space systems, and identify alternate materials to replace copper conductors.
Technology 3.3.5, Power Conversion and Regulation
The available power on any particular spacecraft will be in a form dictated by the power source and distribution architecture, and the various payloads will then likely require the power in a different form. The purpose of conversion and regulation is to provide the necessary bridge between the power source and payloads, and to regulate this power to within the tolerances required by the payloads. A current issue is the need to space-qualify existing terrestrial high voltage components to replace space qualified components that lag behind the commercial state of the art. Important parameters for improving power conversion and regulation devices include increasing conversion efficiency, operating temperature range, and radiation tolerance.
Technology 3.2.1, Batteries
Batteries are electrochemical energy storage devices that have been flown in space from the beginning. In space batteries must survive a variety of environments and load profiles more demanding than for most terrestrial applications. Many batteries are already proven in space, but a variety of advanced chemistry alternatives have yet to be developed and qualified for spaceflight. NASA missions would benefit from new electrochemical power technologies that provide higher specific energy and/or higher specific power.
Technology 3.1.4, Radioisotope Power Generation
Radioisotope power systems (RPS) have enabled many unique deep-space and planetary exploration missions, making scientific discovery possible. RPSs are based on plutonium-238 and have used thermoelectric converters to provide reliable power for many missions throughout the solar system, with operating lifetimes exceeding 30 years. Future RPSs could be developed to deliver both lower and higher power levels. While RPSs are well-established, there are significant technology issues due to the lack of available plutonium-238. Stirling engines, which require less plutonium-238, are being developed to replace thermoelectric converters. Establishing a reliable, recurring source of plutonium-238 and maturing Stirling engine technology are both critically important for NASA’s future science and exploration programs. The planetary science decadal survey committee cited as “its highest priority for near-term multi-mission technology investment… the completion and validation of the Advanced Stirling Radioisotope Generator” (NRC, 2011, p. 307).
Schedules for space power and energy storage technologies are highly dependent on the level of funding. The schedules are possible if sufficient resources are applied to each item in the roadmap.
TA04 Robotics, Tele-Robotics, and Autonomous Systems
The roadmap for TA04 consists of seven technology subareas: sensing and perception; mobility; manipulation; human-systems integration; autonomy; autonomous rendezvous and docking (AR&D); and robotics, tele-robotics, and autonomous systems engineering. TA04 supports NASA space missions with the development of new capabilities, and can extend the reach of human and robotic exploration through a combination of dexterous robotics, better human/robotic interfaces, improved mobility systems, and greater sensing and perception. The TA04 roadmap focuses on several key issues for the future of robotics and autonomy: enhancing or exceeding human performance in sensing, piloting, driving, manipulating, and rendezvous and docking; development of cooperative and safe human interfaces to form human-robot teams; and improvements in autonomy to make human crews independent from Earth and make robotic missions more capable.
For the TA04 roadmap to describe and provide supporting text for each of the level 3 technologies (like the other roadmaps) it would have to be largely rewritten, and the panel made a number of suggestions for changes to TA04 for it to parallel the other roadmaps. As a result, the steering committee and responsible panel did not have a list of well-defined technologies originally identified in the draft roadmaps, and have recommended a new set of level 3 technologies.
TA04 Top Technical Challenges
1. Rendezvous: Develop the capability for highly reliable, autonomous rendezvous, proximity operations, and capture/attachment to (cooperative and non-cooperative) free-flying space objects.
The ability to perform autonomous rendezvous and safe proximity operations and docking/grappling are central to the future of diverse mission concepts. Major challenges include improving the robustness of the rendezvous and capture process to ensure successful capture.
2. Maneuvering: Enable robotic systems to maneuver in a wide range of NASA-relevant environmental, gravitational, and surface and subsurface conditions.
Current rovers cannot access extreme lunar or martian terrain, eliminating the possibility of robotic access and requiring humans to park and travel on foot in suits. In microgravity, locomotion techniques on or near asteroids and comets are undeveloped and untested. Challenges include developing robotics to travel into these otherwise denied areas, developing techniques to grapple and anchor with asteroids and non-cooperative objects, or building crew mobility systems to move humans into these challenging locations.
3. In Situ Analysis and Sample Return: Develop subsurface sampling and analysis exploration technologies to support in situ and sample return science missions.
A top astrobiological goal and a fundamental NASA exploration driver is the search for life or signs of previous life in our solar system. A significant planetary science driver exists to obtain unaltered samples (with volatiles intact) for either in situ analysis or return to Earth from planetary bodies. Terrestrial drilling technologies have limited applicability to these missions and robotic planetary drilling and sample handling is a new and different capability.
4. Hazard Avoidance: Develop the capabilities to enable mobile robotic systems to autonomously and verifiably navigate and avoid hazards.
Due to the large computational throughput requirements needed to quickly assess subtle terrain geometric and non-geometric properties fast enough to maintain speeds near vehicle limits, robotic systems lag behind the ability of human drivers to perceive terrain hazards at long range.
5. Time-Delayed Human-Robotic Interactions: Achieve more effective and safe human interaction with robotic systems (whether in proximity or remotely) that accommodates time-delay effects.
More effective and safe human interaction with robotic systems has a number of different focuses which range from the potential dangers of proxemic interactions to remote supervision with or without time delays. Remote interactions with robotic systems do not pose the same immediate potential level of danger to humans as close proximity interactions; however, it is often significantly more difficult for a remote human to fully understand the context of the environment in which the robotic system functions and the status of the system.
6. Object Recognition and Manipulation: Develop means for object recognition and dexterous manipulation that supports engineering and science objectives.
Object recognition requires sensing, and requires a perception function that can associate the sensed object with an object that is understood a priori. Sensing approaches to date have combined machine vision, stereo vision, lidar, structured light, and radar, while perception approaches often start with CAD models or models created by a scan with the same sensors that will later be used to identify the object. Major challenges include the ability to work with a large library of known objects, identifying objects that are partially occluded, sensing in poor lighting, estimating the pose of quickly tumbling objects, and working with objects at near and far range. Robotic hands with equivalent or superior grasping ability to human hands would avoid the added complexity of robot interfaces on objects and provide a sensate tool change-out capability for specialized tasks.
TA04 High-Priority Technologies
Technology 4.6.2, Relative Guidance Algorithms
Relative guidance technologies encompass algorithms that determine the desired trajectories to be followed between vehicles performing rendezvous, proximity operations, and/or docking and capture. These algorithms must anticipate applicable environmental effects, the nature of the trajectory change/attitude control effectors in use, and the inertial and relative navigation state data available to the guidance algorithms. The new level 3 technologies of interest provide real-time, onboard algorithmic functionality that can calculate and manage spacecraft maneuvers to achieve specific trajectory change objectives. Relative guidance aligns well with NASA’s needs because it impacts crewed deep-space exploration, sample return, servicing, and orbital debris mitigation.
Technology 4.6.3, Docking and Capture Mechanisms/Interfaces
Docking and capture mechanisms enable the physical capture and attachment, as well as subsequent safe release, of two bodies in space that achieve part of their mission objectives when operating while joined. Development of a physical docking and capture interface for AR&D operations would greatly simplify the control demands for a working AR&D system. This technology will improve the reliability of AR&D and enable new interfaces that can be employed. Varieties of docking and capture mechanisms enable transfer of crew between delivery and destination vehicles, provide means for attachment of added equipment modules, facilitate execution of robotic servicing missions, and potentially enable grapple/capture of inactive, possibly tumbling spacecraft.
Technology 4.5.1, Vehicle Systems Management and FDIR
The panel combined the related and overlapping topics of integrated systems health management (ISHM), fault detection and isolation and recovery (FDIR), and vehicle systems management (VSM), which together provide the crucial capability for an autonomous spacecraft to operate safely and reliably. ISHM/FDIR/VSM will improve the reliability of future missions by providing a diagnostic capability that helps ground or crew failure assessment and an automated capability to fix/overcome faults; increase robotic mission flexibility in response to failures; and increase crew safety in the event of a detected need for crew escape and abort. This technology is highly aligned
to NASA’s needs because it will impact many missions, such as deep-space exploration, robotic science missions, planetary landers, and rovers.
Technology 4.3.2, Dexterous Manipulation
Dexterous manipulation is a system-level technology that encompasses multiple stand-alone technology areas and has high relevance for several current and future NASA applications including servicing and maintenance of the ISS, remote satellite servicing, on-orbit assembly of larger structures, and applications to remote exploration. Since 1997, NASA has focused on the development of Robonaut, which is now being evaluated on the ISS and approaches the dexterity of a suited astronaut. Development activities to date have focused primarily on human-in-the-loop teleoperation, and limitations of this system do exist because of high bandwidth, low latency communications requirements. NASA could explore options for extending Robonaut technologies and capabilities for operations in large latency and low bandwidth environments. Additionally, the size and weight of Robonaut preclude its use for exploration activities and NASA could benefit from the development of novel actuation technologies that dramatically increase the strength to weight ratio.
Technology 4.4.2, Supervisory Control
Supervisory control is defined as incorporating the techniques necessary for controlling robotic behaviors using higher-level goals instead of low-level commands, thus requiring robots to have semi-autonomous or autonomous behaviors. This increases the number of robots a single human can simultaneously supervise and also incorporates time-delayed supervision. Key components to be addressed include the development of robust high-level autonomous behaviors and control, multi-sensor fusion, clearly understood and usable presentations of information from multiple robots for human understanding, time-delayed interpretation and presentation of robot provided information, haptic feedback, and means for a supervisory control system to handle communication outages. This technology is highly aligned to NASA’s needs due to the impact of reducing the number of personnel required to supervise robotic missions and the number of science and exploration missions to which the technology can be applied.
Technology 4.3.6, Robotic Drilling and Sample Processing
Robotic drilling and sampling processing (RDSP) technologies will improve the science return of robotic science missions to small bodies, moons, and planets, and will also benefit in situ resource utilization for human spaceflight to the moon and small bodies. The development of new robotic drilling, drill-like, and coring technologies coupled with sample processors will have a major beneficial impact on the quality of planetary science returned by future missions due to the relatively uncontaminated, unaltered, and volatile-rich nature of the samples acquired by the next generation of RDSP technology.
Technology 4.2.1, Extreme Terrain Mobility
Extreme mobility encompasses all ground or surface-level mobility. Extremely mobile platforms will be a critical component to both the success and diversity of extraterrestrial body exploration and determining the terrain that will be traversed. In addition, higher degrees of mobility serve to complement autonomy. This technology provides NASA with the capability to maneuver its surface vehicles in extreme terrain in order to “follow the water”— a high-priority science focus for Mars and lunar science missions, and is applicable to any exploration mission, human or robotic, to a planetary (or lunar) surface.
Technology 4.2.4, Small Body/Microgravity Mobility
Operating robots in microgravity poses many challenges and is particularly difficult without fixing or tethering to grounded structures. Even simple tasks such as turning a screw can be extreme challenges to mobile platforms that are not attached to other structures. The development of adaptive mobility systems with complementary perception and autonomy are key elements to performing exploration and sample return missions in tight spaces and microgravity environments. Variable or dynamic CG capabilities can greatly enhance the ability of platforms to move around and perform meaningful work by dynamically shifting the CG in conjunction with the motion of vehicles. This technology is well aligned with NASA’s goals related to the exploration of small bodies both
robotic and with crew, making this a critical technology for future missions; therefore, the panel designated this as a high-priority technology because the NASA 2010 Authorization Act (P.L. 111-267) has indicated that small body missions (to near-Earth asteroids) should be an objective for NASA human spaceflight beyond Earth orbit. If this goal is pursued as a high NASA priority, it would likely also require precursor robotic missions to small body surfaces with applicable mobility capability.
TA05 Communication and Navigation
TA05, Communication and Navigation, consists of six technology subareas: optical communication and navigation; radio frequency communication; internetworking; position, navigation, and timing; integrated technologies; and revolutionary concepts. Communication links are the lifelines to spacecraft, providing commanding, telemetry, and science data transfers as well as navigation support. Therefore, the Communication and Navigation technology area supports all NASA space missions. Advancement in communication and navigation technology will allow future missions to implement new and more capable science instruments, greatly enhance human missions beyond Earth orbit, and enable entirely new mission concepts.
Before prioritizing the level 3 technologies in TA05, several changes were made to the TA05 roadmap: Technologies 5.4.1 Time-keeping and 5.4.2 Time Distribution have been merged, and Technology 5.6.7 Reconfigurable Large Apertures has been renamed “Reconfigurable Large Apertures Using Nanosat Constellations.”
TA05 Top Technical Challenges
1. Autonomous and Accurate Navigation: Meet the navigation needs of projected NASA missions by developing means for more autonomous and accurate absolute and relative navigation.
NASA’s future missions include diverse navigational challenges that cannot be supported with current methods, such as precision position knowledge, trajectory determination, cooperative flight, trajectory traverse, and rendezvous with small bodies. Additionally, NASA spacecraft will need to perform these tasks farther from Earth and more autonomously.
2. Communications Constraint Mitigation: Minimize communication data rate and range constraints that impact planning and execution of future NASA space missions.
A recent analysis of NASA’s likely future mission set indicates that communications performance will need to grow by about a factor of ten every ~15 years in order to keep up with projected robotic mission requirements and missions will additionally continue to be constrained by the legally internationally allocated spectral bandwidth. Many of the complex tasks of future missions are hampered by keeping Earth in the real-time decision loop, which can be mitigated by making decisions closer to the platform, minimizing reliance on Earth operations. Advancements in communications and navigation infrastructure will allow information to be gathered locally and computation to be performed either in the spacecraft or shared with nearby nodes.
3. Information Delivery: Provide integrity and assurance of information delivery across the solar system.
Future missions will include international partnerships and increased public interaction, which implies increased vulnerability to information compromise. As internetworking extends throughout the solar system, the communications architecture needs to operate in a safe and secure manner.
TA05 High-Priority Technologies
Technology 5.4.3, Onboard Autonomous Navigation and Maneuvering Systems
Onboard autonomous navigation and maneuvering (OANM) techniques are critical for improving the capabilities and reducing the support requirements for many future space missions, and will reduce the dependence on routine position fixes from Earth, freeing the communication network for other tasks. The onboard maneuver planning and execution monitoring will increase the vehicle agility, enabling new mission capabilities and reducing costs by eliminating the large work force required to support routine spacecraft operations. The alignment of this technology to NASA’s needs is high because it will impact deep-space exploration with crew, robotic science missions, planetary landers, and rovers.
Technology 5.4.1, Timekeeping and Time Distribution
Underlying NASA’s communications and navigation infrastructure are atomic clocks and time transfer hardware and software. New, more precise atomic clocks operating in space, as well as new and more accurate means of time distribution and synchronization of time among such atomic clocks, will enable the infrastructure improvements and expansion NASA requires in the coming decades. Advances in timekeeping and distribution of several orders of magnitude were judged to provide major benefits, since increased precision of timekeeping and transfer leads to increased precision of relative and absolute position and velocity which in turn provides better starting solutions to enable autonomous rendezvous, docking, landing, and formation flying remote from Earth. Alignment with NASA’s needs is considered high due to the substantial impact of the technologies on multiple missions in multiple mission areas including human and robotic spaceflight involving rendezvous, relative station keeping, and landing missions.
Technology 5.3.2, Adaptive Network Topology
Adaptive network topology (ANT) is the capability for a network to change its topology in response to either changes or delays in the network, or additional knowledge about the relationship between the communication paths. ANT includes technologies to improve mission communications, methods of channel access, and techniques to maintain the quality of signal across dynamic networks to assure successful exchange of information needed to accommodate increased mission complexity and achieve great mission robustness. The benefit of this technology to NASA is due to the future multi-element missions that will require advanced network topologies, which will need to be adaptive to remain robust for their applications.
Technology 5.5.1, Radio Systems
Radio systems technology focuses on exploiting technology advances in RF communications, PNT, and space internetworking to develop advanced, integrated space and ground systems that increase performance and efficiency while reducing cost. While this technology can benefit from individual advances in many of the other level 3 technologies in TA05, this entry focuses on the challenges associated with integration of these advancements into operational systems. Advancements in radio systems integration focus on one of the highest-priority technical challenges within TA05: Minimize communications constraints on data rate and range that impact planning and execution of future NASA space missions. The steering committee assessed the benefit of radio systems technologies as resulting in major mission performance improvements due to the potential to improve throughput, versatility, and reliability with lower SWAP impact on the host spacecraft. The alignment to NASA needs is high because improvements in communication systems will impact nearly every NASA spacecraft, including near-Earth, deep-space, and human exploration missions.
All NASA missions require communication and navigation to some degree, so the priorities developed in this section are mostly independent of the mission mix, and in most cases, the prioritization of communication and navigation technologies is not impacted by specific missions in the mission model.
TA06 Human Health, Life Support, and Habitation Systems
TA06 includes technologies necessary for supporting human health and survival during space exploration missions and consists of five technology subareas: environmental control and life support systems and habitation systems; extravehicular activity systems; human health and performance; environmental monitoring, safety, and emergency response; and radiation. These missions can be short suborbital missions, extended microgravity missions, or missions to various destinations, and they experience what can generally be referred to as “extreme environments” including reduced gravity, high radiation and UV exposure, reduced pressures, and micrometeoroids and/or orbital debris.
The panel noted that unlike some of the roadmaps which contained multiple technologies for a design solution, TA06 was broader in scope and often vague with respect to technology descriptions. The five level 2 technology areas should be considered enabling systems rather than discrete technologies, as can the level 3 areas, and the panel was therefore required to review level 4. Despite the lack of technical detail, the panel concurred with NASA on the level 3 technical topics with the exception of topic 6.5.4 Space Weather. It concluded that space weather should be removed from this roadmap and possibly identified as a separate interagency roadmap. 6.5.4 was then restructured and renamed “Human Radiation Prediction.”
TA06 Top Technical Challenges
1. Space Radiation Effects on Humans: Improve the understanding of space radiation effects on humans and develop radiation protection technologies to enable long-duration human missions.
Missions beyond low Earth orbit (LEO) present an expanded set of health hazards for a crew and lifetime radiation exposure is already a limiting flight assignment factor for career astronauts on the ISS. Human health radiation models for predicting health risks are currently hampered by large uncertainties based on the lack of appropriate in situ data. Without the collection of in situ biological data to support the development of appropriate models, as well as the development of new sensors, solar event predictions, and radiation mitigating designs, extended human missions beyond LEO may be beyond acceptable risk limits for both human health and mission success. An integrated approach is needed to develop systems and materials to protect crewmembers, and space weather technologies must be upgraded so that the radiation environment is well characterized and solar events can be forecasted from at least Earth to Mars.
2. Environmental Control and Life Support Closed Loop Systems: Develop reliable, closed-loop environmental control and life support systems (ECLSS) to enable long-duration human missions beyond low Earth orbit.
ECLSS for spacesuits, spacecraft, and surface habitats beyond Earth orbit is critical for safety and mission success. In missions without early return capability or remote safety “depots,” the ECLSS system must be 100 percent reliable or easily repairable. Current ISS experience with both the U.S. and Russian segments shows significant rates of ECLSS hardware failures, and the systems should undergo further assessment prior to implementation. Additionally, new propulsion capabilities that reduce mission duration would have a positive impact on system design by reducing exposure to impacts.
3. Long-Duration Health Effects: Minimize long-duration crew health effects.
The accumulated international experience with long-duration missions to date reveals that physical and behavioral health effects and adverse events will occur, and are likely to be life threatening in the absence of correct diagnosis and effective treatment, not all of which can be predicted. Thus, autonomous, flexible, and adaptive technologies and systems to promote long-duration health and effectively restore it when accident or illness occurs are judged to be of high priority. Areas of interest include adverse effects of reduced gravity (such as bone loss, muscular and cardiovascular deconditioning, and neurovestibular disorders), in-flight surgery capability in microgravity environments, autonomous medical decision support and procedures management, and in-flight medical diagnosis enabled by biomedical sensors and “laboratory on a chip” technologies.
4. Fire Safety: Assure fire safety (detection and suppression) in human-rated vehicles and habitats in reduced gravity.
Research and testing are needed to understand why current fire detecting sensors have failed to detect smoldering electrical fires, and to develop more efficient and less hazardous fire suppression systems and remediation capabilities that do not impair ECLSS components and/or processes.
5. EVA Surface Mobility: Improve human mobility during extravehicular activity in reduced gravity environments in order to assure mission success and safety.
Since the Apollo lunar missions, relatively little supported research has taken place on space suits for environments other than microgravity. Differences in Apollo and future planetary suits will include the effects of long-term exposure to microgravity en route, prior to reduced gravity EVA operations for significant surface durations. Critical issues for research in this area include the effects of various reduced gravity levels on gait, posture, and suited biomechanics, and the use of advanced materials and techniques for extending life, enabling ease of maintenance, and reducing the effect of surface dust on bearings, seals, and closure mechanisms. Benefits exist from thorough integration of rovers, pressurized habitats, and robotic assist vehicles in extended surface operations. Innovative technologies providing sensory, data management, and actuation assistance to the suit wearer must be developed and assessed.
TA06 High-Priority Technologies
A total of 14 high-priority technologies were identified for TA06, which have been grouped into five theme areas: Radiation (5), ECLSS/Habitation (4), Human Health/Performance (1), EVA Systems (2), and Environmental Monitoring/Safety (2).
NASA-supported research and a number of NRC studies over the past decade have confirmed radiation as responsible for many of the unsolved health issues of exploration missions. Therefore the highest-priority technologies for TA06 relate to radiation and are as follows:
Technology 6.5.5, Radiation Monitoring Technology
The ability to monitor the radiation environment will be critical to ensure the safety of astronauts and mission success. Measuring the local radiation environment, including the secondary particles generated in the shielding, is necessary to ensure that astronauts keep their total exposure “as low as reasonably achievable.” Established technologies are not sensitive to the full range of threat radiation, nor do they give details about the types of particles contributing to the dose. Advances are needed for smaller, lower power dosimeters with active readout, and sensitive to a broad range of radiation.
Technology 6.5.3, Radiation Protection Systems
Radiation protection systems include materials and other approaches to limit astronauts’ radiation exposure. Shielding is a critical design criterion for many elements of human exploration. It is generally considered that shielding alone will not eliminate galactic cosmic ray exposure, but a well-shielded vehicle or habitat could substantially reduce the exposure from solar particle events. The challenge is in finding the optimum approach that reduces radiation exposure while meeting overall mission mass, cost, and other design considerations.
Technology 6.5.1, Radiation Risk Assessment Modeling
Radiation risk is consistently ranked as one of the highest risks to long duration human exploration missions, and risk limits based on current risk assessment models focusing on cancer incidence would be exceeded after only 4 to 6 months in deep space. There are several layers of risk limits included in NASA’s permissible exposure
limits, and quantification of certain aspects is dominated by a significant uncertainty. Reducing the biological uncertainties would have significant benefits in reducing the cancer uncertainty, quantifying the value of alternative shielding, and quantifying the efficacy of possible radiation mitigation countermeasures.
Technology 6.5.4, Human Radiation Prediction
The ability to forecast the radiation environment, particularly solar particle events and periods of intense ionizing radiation associated with solar storms, is critical to ensuring the safety of astronauts and mission success. The implementation of improved forecasting would improve mission effectiveness and enable more cost effective mitigation strategies by increasing the time to respond, reducing the time spent under shelter, and avoiding false alarms.
Technology 6.5.2, Radiation Mitigation
It is generally considered that shielding alone will not eliminate galactic cosmic ray exposure; therefore there is a need to explore biological/pharmacological countermeasures to mitigate the effect of continuous radiation exposure, as well as to limit the severity of acute radiation effects should an astronaut be exposed during a solar particle event to a significant dose of radiation.
Technology 6.1.4, ECLSS Habitation
The habitation technology area focuses on functions that closely interface with life support systems, including food production, food preparation/processing, crew hygiene, metabolic waste collection and stabilization, clothing/laundry, and re-use/recycling of logistics trash. These technologies provide food, sanitation, comfort, and protection for space-faring crew.
Technology 6.1.3, ECLSS Waste Management
Waste management technology safeguards crew health, increases safety and performance, recovers resources, and protects planetary surfaces. Key areas of concern for this technology include volume reduction, stabilization, odor control, and recovery of water, oxygen and other gases, and minerals.
Technology 6.1.2, ECLSS Water Recovery and Management
This technology provides a safe and reliable supply of potable water to meet crew consumption and operational needs. Due to the tremendous launch mass of water for an entire transit mission and impracticality of resupply from Earth, water recovery from waste-water is essential for long-duration transit missions.
Technology 6.1.1, ECLSS Air Revitalization
Air revitalization is essential for long-duration missions and includes carbon dioxide removal, carbon dioxide reduction, oxygen supply, gaseous trace contaminant removal, particulate removal, temperature control, humidity removal, and ventilation.
Technology 6.3.2, Long-Duration Crew Health
The accumulated international experience with long-duration missions to date reveals and predicts a simple truth, that physical and behavioral health effects and adverse events will occur. Autonomous, flexible, and adaptive technologies and systems to promote long-duration health, and effectively restore it when accident or illness
3During the execution of this study, the NRC completed its report titled Recapturing a Future for Space Exploration: Life and Physical Sciences Research for a New Era (April 2011), which represents a more in-depth review of subject matter covered in TA06.3, Human Health and Performance
occurs, are judged by the panel to be of high priority. Among the long-duration health-related technologies, the panel identified artificial gravity evaluation/implementation as a game-changing technology with the potential to mitigate bone loss, muscular and cardiovascular deconditioning, and neurovestibular disorders. The highest-priority technologies within this category include in-flight surgery capability in microgravity environments; autonomous medical records, informatics, and procedures management; and in-flight medical diagnosis.
Technology 6.2.1, EVA Pressure Garment
Pressure garments constitute the anthropomorphic articulated spacecraft in which each EVA crew member works and survives. Ideally pressure garments should be easy to don and doff, highly articulated and readily adjustable to the kinematics of the wearer’s body, and able to minimize additional forces and torques which the wearer must overcome to accomplish all tasks. The current operational technology for pressure garments represents incremental changes to those developed more than 30 years ago; thus, significant potential exists for substantial increases in performance and operational capabilities.
Technology 6.2.2, EVA Portable Life Support Systems
Although they are not critical to basic functionality, and all portable life support system functions are limited in non-spaceflight applications, both thermal control and carbon dioxide capture were assigned high priority for special attention. Increasing the capacity, reliability, and maintainability of a personal life support system, while extending duration and reducing on-back weight for the user, are important but difficult goals.
Technology 6.4.2, Fire Detection and Suppression
This technology is concerned with ensuring crew health and safety by reducing the likelihood of a fire and, if one occurs, minimizing risk to crew, mission, and/or systems. Areas of research include fire prevention, fire detection, fire suppression, and a proposed free-flying fire test bed.
Technology 6.4.4, Fire Remediation
The panel elevated this technology to high priority status based on Mir, ISS, and space shuttle experiences with fire and post-fire remediation. The issues behind the failures which have occurred need to be thoroughly understood and corrected before long-duration mission are conducted. When vehicle abandonment is not an option, systems must operate throughout the mission, and situational awareness is critical to survival, not just mission success.
Additional comments are detailed in Appendix I.
TA07 Human Exploration Destination Systems
The roadmap for TA07, Human Exploration Destination Systems, includes six technology subareas: in situ resource utilization, sustainability and supportability, advanced human mobility systems, advanced habitat systems, missions operations and safety, and cross cutting technologies. The technologies included in TA07 are necessary for supporting human operations and scientific research during space exploration missions, both in transit and on surfaces. Roadmap TA07 is much broader in scope than other roadmaps, and the six level 2 technology areas of TA07 should be considered enabling systems, rather than competing discrete technologies, all of which are required for mission success. Before prioritizing the level 3 technologies, the steering committee made a number of substantial changes to the TA07 roadmap, which have been enumerated in more detail in the related appendix (Appendix J).
TA07 Top Technical Challenges
1. In Situ Resource Utilization (ISRU) Demonstration: Develop and demonstrate reliable and cost beneficial ISRU technologies for likely destinations to reduce cost and enhance and/or enable productive long-duration human or robotic missions into the solar system.
ISRU capabilities directly impact the deployment and success of exploration missions, having the potential to greatly reduce the cost while increasing the human safety margin and likelihood of mission success and extending mission lifetimes for robotic missions. Key technical challenges are the in situ characterization of the raw resources, demonstration of resource recovery and beneficiation, establishment of the optimum processes under the relevant gravity environment, and production of the strategic products necessary to support future explorations missions.
2. Dust: Characterize and minimize the impact that dust in destination environments will have on extravehicular activity (EVA), rover, and habitat systems.
Dust is a critical environmental hazard. Although dust samples from the Apollo landing sites have been well characterized, little is known about the composition and particle size of unexplored areas of the Moon and Mars. This information is needed in order to develop dust-mitigating technologies for EVA, design requirements for rover treads, and simulants for ISRU.
3. Supportability: Invest in autonomous logistics management, maintenance, and repair strategies in order to reduce mission costs and improve probabilities of mission success.
Improving supportability for long duration missions requires a “launch to end of mission” concept of operations that incorporates highly reliable, maintainable, and repairable systems with fully integrated autonomous logistics management. Reuse and recycling also will be required to reduce the logistics burden of resupply. Supportability systems should be integrated into the design of the systems themselves at the outset, ensuring vehicle systems can be easily maintained with a minimum of crew. Without significant supportability, requirements for future missions to distant destinations should specify a high level of reliability.
4. Food Production, Preservation, and Processing: Develop a food subsystem, as part of a closed-loop life support system, to provide fresh food and oxygen and to remove atmospheric carbon-dioxide during long duration missions.
Food systems for long duration missions are required in order to reduce the costs of up-mass and resupply, habitat volume, and consumables storage requirements at exploration sites. Human spaceflight to distant destinations requires that the nutritional needs of the crew be met for long periods of time.
5. Habitats: Develop space and surface habitats that protect the crew, implement self-monitoring capabilities, and minimize crew maintenance time.
Future human missions to distant destinations will almost certainly involve mission durations equal to or beyond those attempted to date and mass will likely be much more highly constrained. Practically nothing is currently known about humans living, working, and being productive for long periods of time in reduced gravity environments such as the Moon and Mars. Future habitats will need to provide radiation shielding, accommodate long-term exposure to dust, provide a highly reliable habitable volume for months or perhaps years, while additionally accommodating serious medical and surgical intervention, provisioning for world-class research equipment, and still providing a comfortable and sustainable living environment.
6. Surface Mobility (Rovers and EVA): Develop advanced rovers and EVA systems for large-scale surface exploration.
In the case of much longer missions to the Moon than previously attempted, and ultimately Mars, enhanced surface mobility at all levels will improve the science return of exploration missions. A comprehensive program of geological exploration needs access to high slopes, loose and unstable surfaces, and the subsurface access via drilling or excavation. Technology issues such as wheel-soil interactions, optimum mobility platform design, and high-reliability mechanisms with high tolerance for dust and exposure to extreme environments must be addressed.
TA07 High-Priority Technologies
The panel identified 11 high priority technologies in TA07. These technologies have been grouped into five theme areas: ISRU (3), Cross Cutting Systems (2), Sustainability and Supportability (3), Advanced Human Mobility (1), and Advanced Habitat Systems (2).
Technology 7.1.3, In Situ Resource Utilization (ISRU) Products/Production
ISRU potentially carries huge economic benefits if destination resources can be utilized to produce key products for exploration, including return propellants, oxygen, water, fuel, metals, concrete, glasses and ceramics, fabrics/textiles/fiber, volatile gases, and plastics and other hydrocarbons. This technology is considered game-changing because it would significantly reduce the cost of and enhance the productivity of long-duration human or robotic missions. The production of oxygen, water, fuel, metals, and building/construction materials would be particularly beneficial, and these capabilities would be in strong alignment with NASA’s human exploration program needs. Development of system components and autonomous plant operations also ranks high in benefits and alignment.
Technology 7.1.4, ISRU Manufacturing/Infrastructure
This area encompasses a number of technologies, including in situ infrastructure, in situ manufacturing, in situ derived structures, regolith deep excavation for infrastructure, spare parts manufacturing, and regolith stabilization. This area offers high benefit and alignment to NASA’s needs due to the potential for reducing launch costs through reduction of up mass volume and mass.
Technology 7.1.2, ISRU Resource Acquisition
This ISRU element pertains to collecting and acquiring the raw materials to be used and/or processed into the appropriate product or use, and involves a number of subcategories, including regolith and rock acquisition, atmospheric acquisition, material scavenging and resource pre-processing, cold-trap technologies, shallow excavation of dry regolith, and excavation of icy regolith. These technologies will benefit NASA due to their contribution to the reduction in launch costs through reduced up mass and volume.
Technology 7.6.3, Dust Prevention and Mitigation
Dust prevention and mitigation is an exceptional challenge and potential health risk for planetary missions. The development of technologies that mitigate the deleterious effects of dust will require knowledge of the chemistry and particle size distribution of the dust. For missions that entail longer stays and/or increased numbers of EVAs, or that involve dust properties that humans have not yet personally encountered (e.g., Mars), the imperative to preclude dust intrusion into the habitation areas, including the EVA suit, is essential.
Technology 7.6.2, Construction and Assembly
This category covers techniques and technologies for assembling structures anywhere in space which are too large, too heavy, or both to be launched in a single mission. Other than large module berthing performed routinely
in the construction of ISS, most of the functionality of this technology area is readily available on the Earth but has not been adapted to spaceflight. It allows moving beyond deployable structures or modular assembly to erectable structures, including possible use of structural components obtained and fabricated in situ. There are also particular technologies of relevance to reduced gravity situations. All hardware developed for construction and assembly will have to be long-term suitable for the relevant environments and use alternative modes of achieving robustness and accuracy other than the use of massive body components.
Sustainability and Supportability
Technology 7.2.1, Autonomous Logistics Management
Autonomous logistics management includes the integrated tracking of location, availability, and status of mission hardware and software to facilitate decision making by the team with respect to consumables usage, spares availability, and the overall health and capability of the vehicle and subsystems. This system would automatically update the location of hardware items as they were moved around the vehicle or habitat, track life cycle times and conditions of equipment, and inform the mission team of resupply needs based upon the same. The potentially long duration of future missions coupled with long response times for resupply makes it imperative not only that the health of the vehicle and habitat be known, but also that the mission team know the failure tolerance of the integrated system.
Technology 7.2.4, Food Production/Processing/Preservation
The ability to reduce the volume, waste, and mass associated with the mission food supply must be a priority for the development team, as it will be one of the limiting consumables in any long endurance trip. In addition to the need to simply provide caloric intake for the crew, the food supply must provide the proper nutritional balance to ensure crew health during long duration missions.
Technology 7.2.2, Maintenance Systems
The inability to return faulty equipment to Earth before end of mission, coupled with potentially long resupply times, enhances the value of equipment designs that facilitate servicing by the crew— or eliminate the need for crew servicing. Intelligent/smart systems that autonomously determine and report their status, display graceful degradation, and are self-repairing will be valuable to habitat and vehicle development.
Advanced Human Mobility Systems
Technology 7.3.2, Surface Mobility
Surface mobility technologies are of high priority to the Moon and Mars because they enable scientific research over a large area from a single landing site and because they make dispersed landing areas acceptable. The ability to travel great distances over the lunar or martian surface is imperative for conducting large-scale scientific investigations in these environments.
Advanced Habitat Systems
Technology 7.4.2, Habitat Evolution
Advanced conceptual habitat systems would advance the state of the art, provide a higher level of safety and reliability, and mitigate the long-term effects of microgravity and/or radiation exposure to crew on prolonged transits to and from remote destinations. Habitat evolution was rated of critical importance and includes integrated systems, self-repairing materials, inflatable structures, and “cyclers” (solutions that allow the establishment and long-term utilization of transfer habitats between space destinations). These could also allow the use of substantial in situ resources to provide sufficient mass shielding.
Technology 7.4.3, Smart Habitats
This area involves the development of advanced avionics, knowledge-based systems, and potential robotic servicing capabilities to create long-term habitats with significantly reduced demands on human occupants for diagnosis, maintenance, and repair. While studies of three-person crews for ISS showed that about 2.5 crew was required to maintain space systems, this task envisions advanced habitation systems that augment the crew by providing many of the functions currently performed by mission control, and ultimately by the crew itself.
Additional information on development and schedule changes appears in Appendix J.
TA08 Science Instruments, Observatories, and Sensor Systems
The TA08 roadmap addresses technologies that are primarily of interest for missions sponsored by NASA’s Science Mission Directorate and are primarily relevant to space research in Earth science, heliophysics, planetary science, and astrophysics. TA08 consists of three level 2 technology subareas: remote sensing instruments/sensors, observatories, and in situ instruments/sensors. Before prioritizing the level 3 technologies, a number of changes were made to the TA08 roadmap, which are further detailed in the relevant appendix (Appendix K). NASA’s science program technology development priorities are generally driven by science goals and future mission priorities recommended in NRC decadal survey strategy reports; therefore, those priorities were considered in evaluating TA08 level 3 technologies (NRC, 2003, 2007, 2010, 2011).
TA08 Top Technical Challenges
1. Rapid Time Scale Development: Enable the exploration of innovative scientific ideas on short time scales by investing in a range of technologies that have been taken to sufficiently high TRLs and that cover a broad class of applications so that they can be utilized on small (e.g., Explorer and Discovery-class) missions.
Innovative ideas need to be tested and evaluated on a rapid time scale in order to be brought to maturity, but to accomplish this, there needs to be inexpensive and routine access to space for technology demonstration.
2. Low-Cost, High-Performance Telescopes: Enhance and expand searches for the first stars, galaxies, and black holes, and advance understanding of the fundamental physics of the universe by developing a new generation of lower-cost, higher-performance astronomical telescopes.
Cosmologically important astronomical objects are very distant and produce faint signals at Earth, the measurement of which requires much larger effective telescope collecting areas and more efficient detector systems, spanning the range of the electromagnetic spectrum. This goal requires new, ultra-stable, normal and grazing incidence mirrors with low mass-to-collecting area ratios.
3. High-Contrast Imaging and Spectroscopy: Enable discovery of habitable planets, facilitate advances in solar physics, and enable the study of faint structures around bright objects by developing high-contrast imaging and spectroscopic technologies to provide unprecedented sensitivity, field of view, and spectroscopy of faint objects.
Among the highest-priority and highest-visibility goals of the space science program is the search for habitable planets and life upon them. Only technologies that are fully developed and demonstrated to a high level will facilitate the large, expensive missions needed to achieve this goal.
4. Sample Returns and In Situ Analysis: Determine if synthesis of organic matter may exist today, whether there is evidence that life ever emerged, and whether there are habitats with the necessary conditions to sustain life on other planetary bodies, by developing improved sensors for planetary sample returns and in-situ analysis.
The needed technologies include integrated and miniaturized sensor suites, sub-surface sample gathering and handling, unconsolidated-material handling in microgravity, temperature control of frozen samples, portable geochronology, and instrument operations and sample handling in extreme environments.
5. Wireless Systems: Enhance effectiveness of spacecraft design, testing, and operations, and reduce spacecraft schedule risk and mass by incorporating wireless systems technology into spacecraft avionics and instrumentation.
Current ground-based network technologies will need to be adapted and improved to accommodate very high data rates, provide high throughput and low latency wireless protocols, support a myriad of avionics interfaces, and be immune to interference.
6. Synthetic Aperture Radar: Enable the active measurement from space of planetary surfaces and of solid-Earth and cryosphere surface deformation and monitoring of natural hazards by developing an affordable, lightweight, deployable synthetic aperture radar antenna.
Synthetic aperture radar can provide unique information regarding such natural phenomena as earthquakes, volcanoes, and glacier surges. In addition, synthetic aperture radar can enable measurements of planetary surfaces, such as geologic features on the cloud-shrouded surfaces of Venus or Titan. Major advances can come either via a large single structure or apertures distributed across two or more spacecraft and will additionally depend on advances in high-performance computing in space.
TA08 High-Priority Technologies
Technology 8.2.4, High-Contrast Imaging and Spectroscopic Technologies
Development of these technologies would enhance high-dynamic-range imaging and support exoplanet imaging, enabling the discovery of potentially habitable planets, facilitating advances in solar physics, and enabling the study of faint structures around bright objects. This technology would provide substantially increased sensitivity, field of view, and spectroscopy of exoplanetary systems, with many subsidiary applications such as solar physics and the study of faint structures around bright objects.
Technology 8.1.3, Optical Systems (Instruments and Sensors)
Two optical systems technologies are of particular interest: active wavefront control and grazing-incidence optical systems. Active wavefront control enables the modification of mirror figure and alignment in response to external disturbances, allowing automated on-orbit alignment of optical systems and the use of lightweight mirrors and telescopes. This technology closely aligns with NASA’s need to develop the next generation of large-aperture astronomical telescopes, lightweight laser communication systems, and high-performance orbiting observatories for planetary missions. Further development in grazing-incidence optical systems to improve spatial resolution by at least a factor of ten, without increasing mass per unit area, is critical for future x-ray astronomy missions. These are game-changing technologies that would enable direct imaging of stars and detailed imaging of energetic objects such as active galactic nuclei.
Technology 8.1.1, Detectors and Focal Planes
Sub-kelvin coolers and high-sensitivity detectors are very high priority for future space astronomy missions and are strongly linked to the top technical challenge of developing a new generation of lower-cost astronomical telescopes. The availability of capable sub-kelvin refrigerators could enable long-duration space missions and could also enable new categories of devices with enormous commercial and social impact, such as superconducting and quantum computing and superconducting electronics. The increased sensitivity of detectors would improve detection magnitude in numerous wavelengths and thereby enable new missions.
Technology 8.3.3 In Situ Instruments and Sensors
In situ instruments and sensors would help determine if synthesis of organic matter may exist today, whether there is evidence that life ever emerged, and whether there are habitats with the necessary conditions to sustain life on other planetary bodies. Geological, geophysical, and geochemical sensors and instrumentation would need to be designed to survive in extreme environments, such as high atmospheric pressure, high or low temperature, and adverse chemistry. This technology is game-changing because it would enable missions to the surface and atmosphere of Venus and the surface and sub-surface of outer planet satellites such as the jovian and saturnian moons.
Technology 8.2.5, Wireless Spacecraft Technology
The use of wireless systems in spacecraft avionics and instrumentation can usher in a new, game-changing methodology in the way spacecraft and space missions will be designed and implemented. To make wireless systems ready for application in spacecraft, current ground based network technologies would need to be adapted and improved to accommodate very high as well as low data rates, provide high throughput and low latency wireless protocols, support a myriad of avionics interfaces, and be immune to interferences including multi-path self-interference. The panel designated this as a high-priority technology because it directly relates to meeting the top technical challenge to enhance effectiveness of spacecraft design, testing, and operations, and reduce spacecraft schedule risk and mass, by incorporating wireless systems architecture into spacecraft avionics and instrumentation.
Technology 8.1.5, Lasers
Lasers are fundamental components of topographic lidars, atmospheric composition probes, and Doppler wind instruments, and advances in laser efficiency and lengthening lifespan are critical to enabling space studies. The panel designated this as a high-priority technology due to its applications value. NASA would be well served by evaluating and encouraging emerging laser technologies as needed to support the ongoing needs of space missions identified in decadal survey reports and by focusing on approaches for qualifying laser systems for space.
Technology 8.1.2, Electronics for Instruments and Sensors
The design of future readout integrated circuitry to support larger detector sizes will require appropriate design, layout, simulation tools, and fabrication, making use of state-of-the-art ASIC technology. This technology is broadly applicable to many categories of NASA missions and there is a strong linkage between these technologies and making progress on the top technical challenge of this roadmap, regarding development and maturation of technologies for small missions in short time scales.
TA09 Entry, Descent, and Landing Systems
The roadmap for TA09, Entry, Descent, and Landing Systems, consists of four sub-technology areas: aeroassist and entry, descent, landing, and vehicle systems technology. Entry, descent, and landing (EDL) is a critical technology that enables many of NASA’s landmark missions, including Earth reentry, Moon landings, and robotic landings on Mars. NASA’s draft EDL roadmap defines entry as the phase from arrival through hypersonic flight, with descent being defined as hypersonic flight to the terminal phase of landing, and landing being from terminal descent to the final touchdown. EDL technologies can involve all three of these mission phases, or just one or two of them. Before prioritizing the level 3 technologies of TA09, a number of changes were made to the roadmap, which have been detailed in the corresponding appendix (Appendix L).
TA09 Top Technical Challenges
EDL has commonly been one of the more challenging areas of NASA missions and has been characterized by significant failures as well as many near misses. Additionally, the panel observed that NASA’s draft EDL roadmap may be too narrow because it is focused on the development of human class, large payload delivery to Mars as the primary emphasis even though before such a mission is undertaken, many more robotic missions requiring EDL advances will be planned and executed.
1. Mass to Surface: Develop the ability to deliver more payload to the destination.
NASA’s future missions will require ever greater mass delivery capability in order to place scientifically significant instrument packages on distant bodies of interest, to facilitate sample returns from bodies of interest, and to enable human exploration of planets such as Mars. As the maximum mass that can be delivered to an entry interface is fixed for a given launch system and trajectory design, the mass delivered to the surface will require reductions in spacecraft structural mass; more efficient, lighter thermal protection systems; more efficient lighter propulsion systems; and lighter, more efficient deceleration systems.
2. Surface Access: Increase the ability to land at a variety of planetary locales and at a variety of times.
Access to specific sites can be achieved via landing at a specific location(s) or transit from a single designated landing location, but it is currently infeasible to transit long distances and through extremely rugged terrain, requiring landing close to the site of interest. The entry environment is not always guaranteed with a direct entry, and improving the entry system’s robustness to a variety of environmental conditions could aid in reaching more varied landing sites.
3. Precision Landing: Increase the ability to land space vehicles more precisely.
A precision landing capability allows a vehicle to land closer to the intended position, and the level of precision achievable at touchdown is a function of the closed loop guidance, navigation, and control (GN&C) design, control authority of the actual vehicle, and the subject environment. Motivations for highly precise landings include targets of interest and safe landing concerns.
4. Surface Hazard Detection and Avoidance: Increase the robustness of landing systems to surface hazards.
One does not know what hazards a landing surface brings until one has actually landed there, and reliance on passive systems alone to land the vehicle safely can be problematic. Active hazard detection methods can quickly optimize safe sites and reduce fuel costs while directly characterizing the landing surface in real time, but require technology development. A practical system for planetary landing must represent a logical compromise among such factors as landing site conditions, pre-mission landing site knowledge, trajectories, and sensors in order to support an overall landing vehicle solution that is simple, reliable, robust, and efficient for safe and robust exploration.
5. Safety and Mission Assurance: Increase the safety, robustness, and reliability of EDL.
Loss-of-mission events during EDL for NASA and the international community have been unacceptably high for Earth-entry and especially planetary entry missions. These events are painful for high-profile robotic missions and can result in tragedy for crewed missions. Adequate safety and mission assurance can be considered a necessary constraint in the mission and vehicle design process. Risk cannot be eliminated entirely from planetary exploration missions; however, this challenge seeks to improve safety and mission assurance while achieving important mission objectives in an affordable manner.
6. Affordability: Improve the affordability of EDL systems.
Improving EDL technology affordability will allow more missions to be flown within fixed and predictable budgets and also will allow new missions previously deemed unaffordable. Affordability needs to be improved either by making it less expensive to transport the same mass or by achieving the same mission objectives with lower mass and therefore lower costs. Affordability also must be balanced with risk so that a mission does not become too expensive in order that it not fail, nor experience so much cost-cutting that failure is likely.
TA09 High-Priority Technologies
Technology 9.4.7, Guidance, Navigation, and Control (GN&C) Sensors and Systems (EDL)
The ability to accurately hit entry corridors, to control the vehicle during entry and descent, to navigate the vehicle during all phases of EDL, and to safely and precisely land a vehicle in hazardous terrain are examples of a high-performing EDL GN&C system. The ability of the GN&C system to achieve its mission objectives is a function of GN&C sensor performance, vehicle actuator ability, and the designer’s ability to craft them sensibly together onboard a capable, real time, computing platform. GN&C sensors and systems are common to all of the foreseen EDL generic reference missions and align extremely well with NASA’s expertise, capabilities, and facilities. This technology is game-changing because it significantly enhances the ability to increase mass to the surface, the ability to land anywhere, and the ability to land at any time.
Technology 9.1.1, Rigid Thermal Protection Systems
Thermal protection systems (TPS) are used to protect the payload of the entry vehicle from the high temperature and high shear flow environment experienced during the hypersonic entry phase. Most NASA flight experience has been with rigid thermal protection systems, where the TPS are installed onto a rigid aeroshell/structure which can handle both high velocity and high heat fluxes but can also account for a large percentage of the entry vehicle mass. Recent research has been focused on the development of lower density ablators which can reduce the overall vehicle mass fraction. For higher-speed entries into the outer planets or their moons that have atmospheres, new materials would need to be developed that can also handle extreme environments that include both high convective and radiative components. This technology is game-changing because advances in this area would enable new missions in extreme thermal environment or reduced mass to increase vehicle payload and performance, far beyond what has been previously achieved.
Technology 9.1.2, Flexible Thermal Protection Systems
Like rigid TPS, flexible TPS can be reusable or ablative, or some combination thereof. Because of their flexible nature, these TPS systems could be packaged into tighter volumes, applied to irregular surfaces, and deployed when necessary, and, in addition to thermal protection, these systems can also be expected to carry significant aerodynamics loads. Because of their flexibility, it might be possible to tailor the shape of the TPS to improve the aerodynamic performance during the hypersonic entry phase to provide lifting and cross range capability, and these materials could also be used to control local boundary layer state and ultimately heating loads. This technology is game-changing because advances in the flexible area could manifest themselves in reductions in both TPS size and weight.
Technology 9.1.4, Deployable Hypersonic Decelerators
Current entry systems employ traditional rigid decelerator architectures to provide thermal protection and deceleration following entry interfaces. The shape and size of rigid devices define aerodynamic performance and in order to improve performance, size becomes the first order driving parameter. Deployable decelerators enhance the drag area of the spacecraft during the early phase of EDL and advancing these technologies could enable the safe landing of larger objects from sub-orbital terrestrial trajectories and enable heavier payloads to successfully arrive at planetary destinations. There are a number of technologies that must be pursued to enable successful deployment of decelerators, and various advantages exist to using rigid or inflatable decelerators. This technology is game-changing because it provides the ability to utilize much larger drag areas and novel vehicle shapes relative to rigid devices, both of which can enhance thermal protection and deceleration following entry interface and thus enable a whole class of new missions.
Technology 9.4.5, EDL Modeling and Simulation
EDL modeling and simulation (M&S) technology provides the ability to conduct computational predictions necessary for robust and efficient design in all phases of EDL missions. This technology includes computational fluid dynamics analysis, finite element modeling, fluid-structural interaction analysis, aerothermodynamics
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 sufficient 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 technology 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.
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).
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 manipulation 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
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 stiffness 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 missions. 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 efficiency 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 performance 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 incorporation 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 overall 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.
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 technology 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 reaction 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 operating 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.
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 nanotechnology. 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 nanotechnology 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
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 computing 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 robustness 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 government organizations wish to maintain domestic sources for these devices, or a technology development effort may
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 acquisition, 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 architectures, 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 implications 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, scientists, 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 encompasses 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.
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 manufactured 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 missions, 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, requiring 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 technologies 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 multifunctional 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
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 materials 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 qualification 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.
Technology 12.3.1, Deployables, Docking and Interfaces (Mechanical Systems)
Many future science missions involving imaging and scientific data collection will benefit from the combination 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 operational 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 improvements 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 consortia 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.
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 environment of launch nor novel approaches that could reduce structural dynamic response, which frequently drive the structural design of spacecraft.
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 consists 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.
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 temperature for scientific instrument support will require near-zero boil-off rates. Multiple technologies in TA14 support
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. Multifunctional 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.
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.
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