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Review of NASA’s Exploration Technology Development Program: An Interim Report 1 Brief Assessments of ETDP Projects This report contains the committee’s brief assessments of the 22 projects constituting NASA’s Exploration Technology Development Program (ETDP). Following a summary of each project’s objectives and status is the committee’s review of the quality of each project, the effectiveness with which the project is being developed and transitioned to the Constellation program, and the degree to which the project is aligned with the Vision for Space Exploration (VSE). Each of the 22 ETDP projects was evaluated on the basis of: The quality of the research, taking into account the research team, facilities, and the plan to achieve the objectives. The effectiveness with which the research is carried out and transitioned to the Exploration program, including progress to date, apparent gaps in the program, and the likelihood that the required technology readiness level (TRL) will be reached. (The committee decided that simply noting gaps, as stated in the study task, was too narrow an objective and that “effectiveness” as defined here was more appropriate.) The degree to which the research is aligned with the Vision for Space Exploration. (Since the VSE includes the statement “in preparation for human exploration of Mars,” the committee chose to highlight any project that did not appear to have considered plans that included this aspect.) In each of these three areas, the committee rated the projects using a flag whose color represents the committee’s consensus view: Gold star. Quality unmatched in the world; on track to deliver or exceed expectations. Green flag. Appropriate capabilities and quality, accomplishment, and plan. No significant issues identified. Yellow flag. May contain risks to project/program. Close attention or remedial action may be warranted. Red flag. This area threatens the success of the project/program. Remedial action is required. (Not used to indicate the degree of alignment with the Vision for Space Exploration.) A summary of the ratings is provided in Table 1-1 at the end of this chapter. A few topics were given two flag colors due to major distinctions between elements in the topic. Detailed observations on each project are presented and gaps within a given project are identified below. The 22 projects assessed, with a short description of each, are as follows: 01 Structures, Materials, and Mechanisms: Technologies for lightweight vehicle and habitat structures and low-temperature mechanisms 02 Ablative Thermal Protection System for the Crew Exploration Vehicle:
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Review of NASA’s Exploration Technology Development Program: An Interim Report Prototype, human-rated, ablative heat shield for Orion (the crew vehicle) and advanced thermal protection system materials 03 Lunar Dust Mitigation: Technologies for protecting lunar surface systems from the adverse effects of lunar dust 04 Propulsion and Cryogenics Advanced Development: Non-toxic propulsion systems for Orion and the Lunar Lander 05 Cryogenic Fluid Management: Technologies for long-term storage of cryogenic propellants 06 Energy Storage: Advanced lithium-ion batteries and regenerative fuel cells for energy storage 07 Thermal Control Systems: Heat pumps, evaporators, and radiators for thermal control of Orion and lunar surface systems such as habitats, power systems, and extravehicular activity (EVA) suits 08 High-Performance and Radiation-Hardened Electronics: Radiation-hardened and reconfigurable, high-performance processors and electronics 09 Integrated Systems Health Management: Design, development, operation, and life-cycle management of components, subsystems, vehicles, and other operational systems 10 Autonomy for Operations: Software tools to maximize productivity and minimize workload for mission operations by automating procedures, schedules, and plans 11 Intelligent Software Design: Software tools to produce reliable software 12 Autonomous Landing and Hazard Avoidance Technology: Autonomous, precision landing and hazard avoidance systems 13 Automated Rendezvous and Docking Sensor Technology: Development of sensors and software to rendezvous and dock spacecraft 14 Exploration Life Support: Technologies for atmospheric management, advanced air and water recovery systems, and waste disposal 15 Advanced Environmental Monitoring and Control: Technologies for monitoring and controlling spacecraft and habitat environment 16 Fire Prevention, Detection, and Suppression: Technologies to ensure crew health and safety on exploration missions
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Review of NASA’s Exploration Technology Development Program: An Interim Report 17 Extravehicular Activity Technologies: Component technologies for an advanced EVA suit 18 International Space Station Research: Fundamental microgravity research in biology, materials, fluid physics, and combustion using facilities on the International Space Station 19 In Situ Resource Utilization: Technologies for regolith (the loose rock layer on the Moon’s surface) excavation and handling, for producing oxygen from regolith, and for collecting and processing lunar ice and other volatiles 20 Fission Surface Power: Concepts and technologies for affordable nuclear fission surface power systems for long-duration stays on the Moon and the future exploration of Mars 21 Supportability: Technologies for spacecraft and lunar surface system repair 22 Human-Robotic Systems/Analogs: Technologies for surface mobility and equipment handling, human-system interaction, and lunar surface system repair 01 STRUCTURES, MATERIALS, AND MECHANISMS Objective The Structures, Materials, and Mechanisms project has two goals. The first is to develop lightweight structures for the lunar landers and surface habitats, which may be used in future modes of the crew exploration vehicle (CEV) and crew launch vehicle (CLV) to save weight and/or cost. The second goal is to develop low-temperature mechanisms for rovers, robotics, and mechanized operations that may need to operate in shadowed regions of the Moon. Status The ETDP structures component of the project focuses on inflatable (expandable) structures for buildings on the surface of the Moon and very large single-segment propellant tank bulkheads made of aluminum-lithium (Al-Li). The materials component consists of parachute material, radiation shielding kit materials, Al-Li for very large propellant tank domes, and composites for thermal radiators. Little in the way of advanced materials for lightweight vehicles, landers, rovers, and habitats was presented. The mechanisms component consists of gear boxes, electric motor sensors, and motor controls for robotic systems that would operate in continuous darkness at the poles. Each project component is based on the application of system engineering principles to provide minimum risk and ensure on-time delivery. Designing, fabricating, and testing a piece of demonstration hardware is involved in each component. This project is staffed and conducted primarily at NASA, with a handful of industry and academic partnerships.
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Review of NASA’s Exploration Technology Development Program: An Interim Report The potential application of lean manufacturing and rapid prototyping technologies needs to be fully explored in the current ETDP. Experience has shown that these technologies can have a significant impact on cost and schedule. Ratings Quality: Yellow Flag Some team members appear to have little or no expertise in their project area. A lack of experience combined with limited interaction with industry can have a serious adverse impact on the quality of work. The lack of interaction with industry has resulted in situations in which similar projects in industry are currently at TRLs of 6-7 whereas the NASA work has not yet reached that level. (TRL is an acronym for technology readiness level; the numerical values are defined in Appendix D.) An example of industry capability is Al-Li structures and welding; in addition, large friction stir weld-spun domes have been demonstrated that are very close to the Ares I requirements. Ti Al Beta 21 S is currently being used by industry and is not being considered by NASA in the VSE program. The project group self-identified some existing manufacturing techniques that were not being used due to licensing issues rather than technology development issues. It also appears that a lack of specific requirements in some cases has allowed in-house projects to float goals and produce simplistic measures of success. Effectiveness in Developing and Transitioning: Yellow Flag The accumulated project elements seem to lack a direct tie-in to an integrated, overarching plan. The objectives for most of the elements are not linked directly to supporting the VSE or Constellation program requirements, which limits their ability to be transitioned to the customer, thus limiting the overall effectiveness of the work. Specific issues: Al-Li manufacturing—friction stir weld-spun domes. Industries have been doing friction stir weld and spun domes for a long time. The main reason for pushing this technology is the 5.5-meter-diameter size. However, other non-NASA organizations have achieved this technology in sizes very close (5.2 m) to what NASA is trying to achieve. The benefit to the Constellation configuration from incorporating this technology with a small change in dimension from the state of the art is not clear. Low-temperature mechanisms. This element has selected a few components and tested them under the cold temperature extremes present on the Moon. However, when asked about specific applications, the project team was unsure. Some components may work individually in the specified environment but may not function as part of higher-level subsystems or systems. Advanced material for parachutes. This element lacks a useful figure of merit. Material is being evaluated for potential application as the CEV parachute material. It was stated that this material has a strength-to-weight ratio approximately twice that of other currently available fibers and, consequently, will yield more than 40 kg in weight savings for the three CEV parachutes. Unanswered is the question of the cost per kilogram to achieve this reduction in weight and the resulting overall gain in system performance. Expandable structures. Using lunar regolith as part of a pressurized architecture is somewhat cumbersome. It is not clear that this is the best design solution because, for example, the abrasive dust in a low-gravity situation could be a menace to equipment and personnel.
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Review of NASA’s Exploration Technology Development Program: An Interim Report Advanced composite structures. Exotic materials, such as lightweight composites, often promise great advantages on paper and sometimes in practice. It was not clear from the presentation how and where these composite materials were going to be applied throughout the Constellation program. The performance benefit or the figure of merit was not clearly identified. Composite materials may potentially provide significant advantages in weight reduction, but studies of system tradeoffs are needed to identify and quantify those gains. No new facilities were identified as needed to validate performance capabilities. Radiation shielding kit. The technology, which proposes a type of blanket or sleeping bag approach as a portable shield, is good as fundamental research. However, unless its specific application to various elements is identified, it is very difficult to see its impact on the exploration programs. The use of this kit was not compared with other competing options. What are the figures of merit? Alignment with the Objectives of the Vision for Space Exploration: Yellow Flag While it is not clear why some specific project work was selected, overall the project elements are proceeding in a timely manner and results are expected to be available to meet VSE and Constellation program schedules. However, the benefit of this work is limited by an apparent lack of specific requirements coming from the Constellation Project Office. The performance benefit for the VSE and Constellation programs may not be fully achieved. There appears to be little in the way of enabling technology in these project elements. Therefore, a strong push for these technologies by the customer is not apparent. 02 ABLATIVE THERMAL PROTECTION SYSTEM FOR THE CREW EXPLORATION VEHICLE Objective Extremely large heat fluxes are experienced by the CEV during reentry from the Moon or Mars. An ablative heat shield is required for thermal protection. The heat shield design and qualification of the thermal protection system (TPS) material represent major technological challenges. The NASA team stated that the present TRL is 4; the TRL needs to be advanced to 6 to support the CEV. Status The team is composed of NASA, the companies producing the materials, and the CEV contractor. The work is being carried out in a coordinated manner and, overall, is of good quality. The currently used metrics are appropriate. It appears that the arc-jet facility at Ames Research Center (ARC) will be upgraded, which will improve its flow simulation capabilities. Material test specimens and TPS materials for the primary and backup CEV heat shields are being produced by aerospace companies. The CEV contractor has built a full-scale heat shield test article and will build the flight heat shield. These developments are being directed and reviewed by NASA to ensure coordinated consideration of reentry mechanical and thermal loads. There is no possibility of alternate technologies being developed within the ETDP. The plan is to have an acceptable TPS design by CEV Preliminary Design Review (PDR) and to have the technology matured by CEV Final Design Review (FDR).
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Review of NASA’s Exploration Technology Development Program: An Interim Report Ratings Quality: Yellow Flag The heat shield is being designed using heating rate predictions from an uncoupled analysis; i.e., the char surface temperatures are assumed to be radiation equilibrium temperatures rather than being calculated from a heat balance for the ablating heat shield. The injection of the pyrolysis gases and char oxidation products (which may significantly change the prediction of the heating rate) is ignored. This approach does not represent the current state of the art and could lead to either an over- or underprediction of the bond-line temperatures late in the entry. Effectiveness in Developing and Transitioning: Yellow Flag Even though 40 years have elapsed since the Apollo 4 flight test and the state of the art in heat shield design has advanced significantly, we still do not have the ability to simulate a lunar-return Earth entry in ground-based facilities. The planned ground-test arc-jet facility improvements are desirable but will not provide an adequate approximation of all flight conditions and cannot be scaled to the full heat shield dimensions. Within the present state of the art, it is not possible to build ground test facilities that will duplicate (or even adequately approximate) flight conditions. Only a reentry flight test at lunar-return velocity and at a scale sufficient to assess the effects of joints and gaps between the heat shield panels will qualify the heat shield for use on a crewed lunar-return mission. The committee was not clear as to whether an uncrewed flight test is planned; if not, this project would be labeled with a red flag. While industry has been involved in producing candidate TPS material, there is no significant involvement of the national laboratories. However, organizations such as Sandia as well as other Department of Energy and Department of Defense laboratories could contribute. Alignment with the Vision for Space Exploration: Yellow Flag Planetary-return heating rates are much higher than lunar-return heating rates. A CEV-like vehicle entering at 13 km/s from Mars will experience peak stagnation point heating rates (convective and radiative) three times greater than the lunar return values. Furthermore, at 13 km/s the stagnation-point heat load is approximately 70 percent radiative whereas for lunar return entries it is less than 25 percent. Therefore, an entirely different heat shield design may be required for reentry from Mars, and hence the present technology does not really support the full VSE. 03 LUNAR DUST MITIGATION Objective Dust was an issue for the Apollo astronauts and it continues to be an issue for the Mars Exploration Rovers (MERs). Dust presents both a health risk (e.g., inhalation, damage to spacesuits) and a mission risk (e.g., obscuring landing sites, causing equipment to overheat). In response to these dust issues, NASA has established the Lunar Dust Mitigation project with the goal of providing the “knowledge and technologies (to TRL 6) required to address adverse dust effects to humans and to
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Review of NASA’s Exploration Technology Development Program: An Interim Report exploration systems and equipment, which will reduce life cycle cost and risk, and will increase the probability of sustainable and successful lunar missions.”1 Status This project has clearly defined requirements that have been delineated into well-stated project plans to bring the TRL to 5. The development objectives of each of these plans were understood by the team members as clearly stated deliverables. Interaction within the NASA organizations seems appropriate. The expertise of dealing with regolith resides within NASA, but outside sources are being sought in appropriate areas where industrial cooperation can benefit the program. The extensibility to Mars appears to be assumed, given that the Moon is the project’s current focus. The team seems to be motivated and enthusiastic about achieving its goals. The team has test plans within the scope of available resources, i.e., test facilities, but the need for full-scale testing is not reflected in the current project plan or the Constellation plan. Individual experiences within the Apollo program are being folded into the development of the projects, except for the overall experience of equipment being crippled by dust contamination on the surface. Ratings Quality: Green Flag The Lunar Dust Mitigation project plan has well-developed requirements and an appropriate layout of program elements to achieve a TRL of 5. Requirements from many sources are driving the correct program development to satisfy the goals. Outside sources have been sought for expertise in dust mitigation within the mining industry—more interaction with hard rock mining would enhance this effort. Small Business Innovation Research (SBIR) projects are also being used to solicit outside expertise and advance the TRL in some areas. Apollo experiences with dust effects are being folded into their technology plans. Component-level testing of various mechanisms in a vacuum environment is a good element of this program. Effectiveness in Developing and Transitioning: Red Flag Low-TRL ideas that would be matured later than 2013 are not being considered currently in SBIR or other programs; this will limit the continuity of new ideas being inserted into this project’s long-term goals. Regolith simulant production in the time necessary to provide testing also poses a risk to this effort. Currently, the risks are very high due to the lack of full-scale, long-term testing for proving the effectiveness of the developed products. A full-scale test facility and testing of equipment (e.g., bearings and seals, robots, EVA suits, crawlers) for long-term exposure are necessary for the ETDP to develop and prove the critical capability of these vital resources on the Moon and Mars. The lack of plans to include a full-scale test facility negatively impacts the effectiveness of the effort in a major way and if left unresolved virtually guarantees failure to reach project goals expressed as TRL 6. Alignment with the Vision for Space Exploration: Yellow Flag The impact of this project on the VSE is clearly enabling, which is understood by the Constellation program. Without control of dust effects, exploration on the surface would be seriously 1 NASA, Small Business Innovation Research and Technology Transfer 2007 Program Solicitations, Chapter 9, Topic X7.04, Surface System Dust Mitigation, available at http://sbir.nasa.gov/SBIR/sbirsttr2007/solicitation/SBIR/TOPIC_X7.html.
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Review of NASA’s Exploration Technology Development Program: An Interim Report compromised. Even robotic precursors could be less effective without this control. This is recognized by the NASA team and contained in its project plans. The yellow rating reflects the lack of any development for the Mars environment, which may have its own problems with dust as shown by MERs, as the lunar environment appears to be the sole focus of this project. 04 PROPULSION AND CRYOGENICS ADVANCED DEVELOPMENT Objective The Propulsion and Cryogenics Advanced Development (PCAD) project is focused on the development of the ascent and descent propulsion systems for the lunar lander. The team is working on three main areas: the descent main engine, the ascent main engine, and reaction control system (RCS) thrusters for the ascent propulsion system. According to NASA, the ascent liquid oxygen/methane (LOX/CH4) main engine is currently at TRL 3, the RCS thrusters are at TRL 4, and the descent main engine is at TRL 5. Status The PCAD team is composed of NASA employees and several contractors for the main engines and the RCS. The contractors include major aerospace companies and smaller companies. The PCAD project is nicely focused on established risk areas for each of the three main projects being worked on. The main customers of PCAD are the Lunar Lander Projects Office and the Orion Crew Module Project Office. For the descent main engine, the current choice of propellants is liquid oxygen/liquid hydrogen (LOX/LH2). This choice was made to meet the lander weight budget because the performance is better than that of storable propellants. Meeting the throttle requirement for this engine (currently about 30 percent but for some versions it could be lower) is mission-enabling for the Lunar Lander. The main risks with this engine are stable throttling, performance, and reliable ignition. For the ascent propulsion system, nitrogen tetroxide/monomethyl hydrazine and LOX/CH4 are under consideration. However, the current technology program is focused only on LOX/CH4, since this is a new propellant combination to be used for this application. The projected benefits of using LOX/CH4 versus hypergolic fuels are higher performance, which translates into weight savings of approximately 180 to 360 kg; lower costs; and a comparable development schedule and achievable reliability. The main challenges to be resolved for the LOX/CH4 engine to be chosen over the storable propellants are reliable ignition (especially after long-term missions on the order of 6 months), performance, and fast start. RCS thrusters using LOX/CH4 are also being developed that are intended to have higher performance and maneuverability than those using storable propellants. In this case, the major risks are reliable ignition, performance, and repeatable pulse width. While Russia, Korea, Pratt & Whitney Rocketdyne, and others are designing or have designed LOX/CH4 engines, they are not designed for a similar application and therefore are not being used as a baseline for comparison with the current ascent engine being developed. Both main engines and the RCS described above minimize the contamination of the vehicle and landing area and improve ground procedures on the launch pad.
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Review of NASA’s Exploration Technology Development Program: An Interim Report Ratings Quality: Green Flag The propulsion work seems to be well coordinated among the primary customers, namely, the Lunar Lander Projects Office (LLPO) and the Orion Crew Module Project Office, the NASA technology development teams from the NASA Glenn Research Center (GRC), the Johnson Space Center (JSC), the Marshall Space Flight Center (MSFC), and the contractors. The existing test facilities seem to be sufficient for this project. For the descent engine, the team is pursuing a LOX/LH2 engine based on the RL-10 and is working with Pratt & Whitney Rocketdyne to develop the new engine. It is tackling critical design issues, such as the injector design. The metrics are well defined and relevant to the development program. The team is aware of the risks it faces. However, there are gaps in the program that the team is aware of but could not address due to insufficient resources: controls, turbomachinery, and high-heat-transfer chambers. For the ascent module, the team is focusing on LOX/CH4 for the reasons mentioned above and wants to mature this technology before the LLPO has to choose between this new technology and hypergolic fuels. The team is very aware of the key parameters it has to demonstrate reliable ignition, performance, and fast start. Its program is well tailored to these objectives. The team is simultaneously carrying on a development program for LOX/CH4 RCS thrusters that would go hand in hand with the main engine. Effectiveness in Developing and Transitioning: Green Flag The LLPO is considering two choices for the main ascent engine: LOX/CH4 and storables. Because the risks associated with developing a LOX/CH4 engine are greater than those associated with developing a storable propellant engine for this application, the decision has been made to focus only on the LOX/CH4 engine in the technology program. As a result of a first set of vehicle studies on both options, LLPO found that a LOX/CH4 engine could result in a weight savings of 180 to 360 kg. As of this writing, the decision as to which type of engine to procure will be made in 2011 or so after the PCAD team has had a chance to investigate in detail the prospect of using LOX/CH4 and has given its results to LLPO and others to allow them to make an informed decision. Within PCAD, the first test results from the two contractors working on the LOX/CH4 engine were not favorable. However, the team has responded quickly to these outcomes and is considering alternate designs. PCAD and LLPO are working closely to feed each other the results from their studies. For the descent engine, the team is carrying only one contractor, Pratt & Whitney Rocketdyne, due to cost constraints, which means that only one design is being considered. However, in terms of transition, they are well positioned since from the beginning the project has had on its team a contractor with the experience to complete the full cycle of design, development, testing, and production. Alignment with the Vision for Space Exploration: Green Flag Being able to develop a LOX/CH4 main ascent engine would be a great plus for Mars exploration since it is amenable to in situ resource utilization. The team has also tried to foresee what requirement changes LLPO might present and has tried to develop flexible designs. For example, its LOX/CH4 engine program is expected to be responsive to thrust changes and the number of the starts required. The PCAD technology development team is also pursuing “green” propellants such as LOX, LH2, and CH4, as opposed to hypergolic fuels, for both the descent and ascent engines, which one can only assume will continue to be the preferred choice for other exploration-class missions.
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Review of NASA’s Exploration Technology Development Program: An Interim Report 05 CRYOGENIC FLUID MANAGEMENT Objective The objective of the Cryogenic Fluid Management project is to develop the technologies for the long-duration storage and distribution of cryogenic propellants in support of all exploration-class missions. The development of these enabling technologies is crucial for various NASA customers in the Constellation program including the Lunar Lander, Earth Departure Stage, and lunar surface operations as well as for the Mars program. Status The scope of this technology project includes a number of interrelated areas: long-duration propellant storage, cryogenic propellant distribution system, and propellant management in a low-gravity environment. A number of design and test qualification tasks under each of these areas have been defined and are being executed per plan in place. The tasks are being performed primarily at various NASA centers, including GRC, MSFC, JSC, ARC, Goddard Space Flight Center (GSFC), and Kennedy Space Center (KSC). A relatively small involvement of external agencies, including universities and small companies, was identified. The current TRLs were stated by the NASA team as follows: propellant storage–TRL 4, propellant distribution–TRL 5, liquid acquisition–TRL 4, and mass gauging–TRL 3. However, based on the current technical maturity, a TRL of 4 for the propellant distribution system would be more appropriate. The plans to achieve the desired TRL of 6 by the PDR of various Constellation elements include a combination of analytical modeling with component and integrated system tests under specified nonspace and simulated space environment. In some cases, such as mass gauging systems, a number of competing systems such as the pressure-volume-temperature system, radio frequency gauge, and optical mass gauge are in the process of being evaluated. Ratings Quality: Yellow Flag The Cryogenic Fluid Management (CFM) project is spearheaded by a very competent group. However, a number of technology gaps may have serious consequences for the overall Exploration program. Testing subscale or full-scale systems under low gravity is essential to demonstrate the applicability of the selected technologies or systems. The achievement of a TRL of 6 or higher before the PDR of various exploration elements may not be realized due to the lack of these essential tests, mostly as a result of funding or scheduling limitations. In some cases, the lack of a fully integrated system test before flight may lead to undesirable risks. It was mentioned that the Constellation Program Office is evaluating the risks associated with bypassing some of these tests or the eventuality of not achieving the desired TRL by the PDR. This position is in direct conflict with the “Enabling Technologies” designation assigned to the CFM project by the Exploration Program Office, given that an enabling technology is understood to be one that must be achieved to enable the success of the mission or an important component of the mission. Effectiveness in Developing and Transitioning: Yellow Flag The involvement of industries and universities appears to be minimal compared to the direct NASA involvement. The analytical modeling work or the subscale-level testing under a nonspace
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Review of NASA’s Exploration Technology Development Program: An Interim Report environment cannot be extrapolated to determine the performance and functions of the full-scale systems under zero- or low-gravity applications. There is a strong possibility of not achieving the desired TRL of 6 by the PDR. The program-level risks for crew safety and mission success associated with this eventuality have not been quantified and articulated. Alignment with the Vision for Space Exploration: Yellow Flag The architectural benefit of using cryogenic propellants in the Exploration program is well understood and identified. The selection of LOX/LH2 for the Earth Departure Stage and the Lander Descent Module provides a significant performance benefit compared to other competing propellant systems. However, a number of technical risks associated with long-duration in-space storage, propellant distribution, and acquisition remain unresolved. Similarly, the same issues exist for the LOX/CH4 propulsion system, which is currently being evaluated for application in the Lander Ascent Module. Lunar surface operations for later and longer missions covering up to 210 days require well-proven technologies for long-term cryogenic storage and fluid transfer between surface assets. However, the relationship and dependencies of the CFM systems and the lunar surface concepts of operations were not described or presented. The applicability of the technologies and the design solutions identified for lunar missions and long-duration missions and Mars and beyond were not addressed. 06 ENERGY STORAGE Objective The objective of the Energy Storage project is to reduce risks associated with the use of lithium batteries, fuel cells, and regenerative fuel cells for the Lunar Lander, lunar surface systems, EVA, and Ares I/V. Major deliverables are rechargeable batteries for lander ascent, EVA, and lunar surface mobility; primary fuel cells for lander descent; and regenerative fuel cells for lunar surface power and surface lunar mobility. Rechargeable batteries and regenerative fuel cells are energy storage devices and cannot by themselves provide all the power needed for long-duration missions; a power source (solar or nuclear) is also needed. The objective is to deliver TRL 5 technologies to Constellation System Requirement Reviews (SRRs) and TRL 6 hardware for their PDRs. Status The battery and fuel cell research is being carried out at GRC, the Jet Propulsion Laboratory (JPL), and a few university and industrial collaborators/contractors. NASA has very good facilities for both battery and fuel cell research and testing. The program is well coordinated among the NASA centers. It is not clear if the current performance targets will meet the future mission requirements. Customer requirements are not yet well established, but presumably will be much better defined in the future. The currently used metrics are based on a bottom-up approach and, in lieu of established customer requirements, are appropriate as a temporary measure. The NASA research effort is quite small compared to that of other agencies and the battery and fuel cell companies. Consequently, by focusing on issues that are specific to its needs rather than trying to make fundamental advances in the technology, the project will reach its goals more effectively and at lower cost. Some NASA-focused issues include low-temperature operation and lightweight packaging for batteries and fuel cell technologies that achieve high performance and long-term reliability without the cost constraints of the commercial market.
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Review of NASA’s Exploration Technology Development Program: An Interim Report The packaging effort for the Portable Life Support System (PLSS) should seek expertise in penetration/shock protection that exists outside this organization—a physical-test-based program by itself will not achieve the packaging and weight reduction goals. Collaboration with ergonomics and human factors experts would sharpen the weight reduction goals. Suit Water Membrane Evaporator technology is being developed from previous NASA research and is sound but offers no breakthroughs. For Rapid Cycle Amine, there is a need to better understand toxicity issues. Metabolic Temperature Swing Absorption was identified through a competitive procurement process, and a company’s funds have taken this technology to a TRL of 3. It is questionable whether this program can be developed mainly through SBIR funding. The variable pressure regulator is very novel and useful for the VSE, a great innovation. The current plan seems achievable, but this was one of the lowest-TRL projects shown. The radiation hardening effort for communications would benefit from increased contacts with industry and the DOD laboratories to achieve the project’s goals. The Power Communications Avionics and Informatics group has developed useful contacts with the DOD in the areas of audio communications, batteries, displays, and speech recognition, which should prove beneficial. Effectiveness in Developing and Transitioning: Yellow Flag Resource limitations negatively impact the EVA team’s ability to tap the knowledge of highly experienced experts and to invest in revolutionary systems. An integrated EVA team (PLSS and suit) would focus goals and would result in better alignment than the current, arbitrarily separated pressure suit effort. The lack of long-term funding presents a substantial risk to this critical element of future planetary surface exploration efforts. During a visit to the EVA Suit Laboratory no new technologies or design concepts were apparent to mitigate the locomotion and mobility issues central to lunar surface exploration missions. No new materials or systems research was presented to address the significant abrasion and dust mitigation problems that will be encountered in the lunar regolith. An environmental facility simulating lunar conditions as closely as possible, including the abrasive lunar regolith, could lead to a significant reduction in the risks associated with long-term exploration on the surface of the Moon. Gaps in the efforts include (1) a fully nested analysis effort to optimize the protection and weight of the PLSS; (2) the incorporation of radiation protection within the suit elements; (3) identification of new heat-rejection technologies, including both passive and active systems such as new materials for the suit, new phase change materials, and alternative designs for the present cooling garment; and (4) consideration for integrating advanced technologies into the overall system rather than relying solely on incremental improvements. Alignment with the Vision for Space Exploration: Yellow Flag The benefit of EVA systems is obvious within the VSE; not providing the enabling EVA systems on time will jeopardize the entire mission. The ability to reduce pre-breathing time will greatly affect operations on the lunar or Mars surface.
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Review of NASA’s Exploration Technology Development Program: An Interim Report 18 INTERNATIONAL SPACE STATION RESEARCH Objective The objectives of the ISS research project are divided into two parts. The second part was not reviewed since it is not exploration related. The goal of the exploration portion is to utilize the ISS as a low-TRL test bed to bring low-TRL technologies to higher TRLs in the areas of life support, fire safety, power, propulsion, thermal management, material technology, habitat design, and so on. The goal of the non-exploratory portion is to sustain U.S. scientific expertise and research capabilities in fundamental microgravity research in the life (non-human) and physical sciences. The U.S. Congress mandated the allocation of at least 15 percent of ISS research to ground-based, free-flyer, and ISS life and microgravity science research that is not directly related to supporting the human exploration program. Status Nearly all exploration-related tasks are research projects aboard the ISS, with a few being ground-based research. All currently funded tasks are carryovers from the original ISS program with a budget that was many times larger in 2005. Some are onboard the ISS and some are scheduled to be delivered by the space shuttle or Soyuz up to early 2009. Ratings Quality: Green Flag The ISS research project will support the following test facilities: microgravity science glovebox (on-orbit), a fluids and combustion facility, and a materials science research rack in the ISS national laboratory. The last two will be launched in the next 2 years. Because they are in use or qualified to be used in the ISS, the test facilities have met the stringent operational and safety requirements imposed by the ISS. The ISS research projects have met some of the goals for research efforts recommended by the National Research Council (NRC): Effects of radiation on biological systems, Loss of bone and muscle mass during spaceflight, Psychosocial and behavioral risks of long-term space missions, Individual variability in mitigating a medical or biological risk, Fire safety aboard spacecraft, and Multiphase flow and heat transfer issues in space technology operations. Four foundational research efforts are targeting effects of gravity dependence on exploration missions: Smoke and Aerosol Measurement Experiment for design of a useful spacecraft smoke detector, A rodent infection model possibly applicable to human spaceflight, Zero Boil-Off Tank Experiment for spacecraft tanks, and Vegetable Production Unit to study space growth of plant species and their supporting equipment along with assessment of crew member reactions.
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Review of NASA’s Exploration Technology Development Program: An Interim Report These projects would satisfy NRC recommendations for research in areas 3, 5, and 6 listed above. There are eight other exploration research efforts related to physical sciences, including fluid physics and combustion science, that are led by university professors and researchers from Glenn Research Center. There are 17 other non-exploratory physical sciences efforts, including fluid physics, combustion sciences, material sciences, and acceleration environment characterization. The principal investigators are mostly university professors. The quality of the research is considered to be good. Effectiveness in Developing and Transitioning: Yellow Flag Since most experiments on the ISS are done for the sake of science with zero gravity, they cannot address the low-gravity applications on the lunar or Mars surfaces. It should be noted that ETDP project 05, Cryogenic Fluid Management, cannot validate its technology in zero or low gravity due to cost and time constraints, and it may not be able to use results from the ISS experiments to support the Constellation program’s development. This is an example of the disconnects or gaps that exist between the ISS research and the ETDP’s customers. Before each project can be sent to the ISS, it has to be assigned a slot in the shuttle or the Soyuz cargo manifest. Months of integration are also required before each flight. Therefore, most of these projects are given a yellow flag by the committee since they cannot meet the time frames required by the ETDP. The ISS project is also perceived as a unique community more of scientists than engineers. The transitioning of results is viewed as indirect because it occurs basically through conference papers and reports. There appears to be no regular communication with other ETDP projects. Alignment with the Vision for Space Exploration: Yellow Flag The Exploratory Research Program on the ISS consists of projects that are at or below TRL 3. Therefore, they do not yet meet Constellation’s needs. The relevancy of such projects is based on endorsement letters from other ETDP projects. The logic is that these research projects may be successfully picked up in the next TRL development for future ETDP projects. However, most projects are carryovers from previous ISS projects and use facilities onboard the ISS. The pool of investigators is from the original ISS research community and the selection is based on the ISS project’s own interpretation of exploration needs rather than the other way around. The perception is that a gap exists between research projects and other ETDP customers such as Constellation. Nonetheless, the projects listed above represent valid scientific research and can be considered to align with future Mars Exploration missions, but the possible application of results to Constellation is not clear. 19 IN SITU RESOURCE UTILIZATION Objective The basic concept of in situ resource utilization (ISRU) is to extract elements and minerals from the land and/or atmospheric resources that are present on the Moon and Mars. The idea of “living off the land” has been investigated for the past two decades. The proposed benefits argue that each kilogram of material that is produced on the Moon or Mars saves funds, launch mass, acquisition time, and payload volume. At roughly $100,000 per kilogram to put material on the Moon, these savings have been shown to be considerable. In addition, by producing needed materials at the base, the crew will be better able to deal with unforeseen emergencies.
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Review of NASA’s Exploration Technology Development Program: An Interim Report The near-term goal is to produce oxygen from lunar regolith for life support at about 1 metric ton per year. The mid-range goal is to produce about 10 metric tons per year to refuel the propellant tanks on the ascent vehicle. The long-range goal is to use extracted metals for fabrication of parts. Status Regolith excavation and transport will be demonstrated by both large and small rovers in analog environments. Oxygen production from regolith is to be demonstrated on the scale of an outpost-scaled plant. A precursor demonstration is being developed. It is hoped that this demonstration can be flown through a partnership with Europe, Japan, or India. There is also some support work, in the form of modeling, regolith simulant development, and facility identification. There are some collaborative programs with the Canadian and Japanese space agencies and limited procurements from industry and academia. Ratings Quality: Green Flag The various efforts under the ISRU project appear to have high quality in both development path layout and the knowledge and abilities of the participants. The project has made good use of the expertise at all relevant NASA research centers and works in a well-coordinated manner. This project has also involved several universities and a few industries. The ISRU technology roadmap is closely linked to NASA’s Science Mission Directorate and has a good link to NASA’s life support development activities. However, the planning between the Lunar Lander work and the ISRU activities is not currently well coordinated enough. According to the NASA presenters, the TRLs of most of the projects are at about 3, with some concepts around 2. The effort could benefit from involvement of more universities and others in investigating new concepts at TRLs of 1-2. An important issue to be resolved is whether the implementation of the equipment needed to produce materials from the lunar regolith costs more than the savings offered by producing the material on-site. Effectiveness in Developing and Transitioning: Red Flag To the extent possible, the ISRU project has taken full advantage of related non-NASA work in a noncritical way, such as drawing on advances in mining technology developed by the Canadians. The risks in achieving the project’s goals are very high due to insufficient resources: SBIRs will not solve this within the necessary time frame for implementation, and relying on foreign partners to maintain the ISRU work is problematic. In addition, this project is different from most of the ETDP projects, since it has no Apollo experience to build on, and without another application in a commercial market there is no non-NASA entity to develop the technology. The committee has identified three technology gaps that inhibit the effectiveness of this project: High-fidelity lunar environment test bed. The lunar environment is a hard vacuum, has large temperature swings, is very dry, and possesses a layer of fine, abrasive dust. All of these conditions may strongly impact the performance or lifetime of robotic systems, mobile transports, heat radiators, and human respiration. Except for low gravity, these conditions can be duplicated on Earth to validate the performance of candidate systems and operations. In addition to environmental testing, there are currently technology gaps due to funding
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Review of NASA’s Exploration Technology Development Program: An Interim Report limitations in lunar soil stabilization studies and operations and control software for startup, operation, and shutdown in low gravity, vacuum, dust, and lunar thermal cycles. NASA’s program lacks a facility that duplicates the dusty environment, vacuum, and thermal cycles of the Moon. Without such testing, no quantification of lifetime margins is possible. Repairs versus spares. This issue actually reflects a philosophical approach to exploration. Historically, missions have been of short duration, and so systems and components were not expected to break down during the missions, and technology was not pushed to extend reliability. For long-duration missions, however, breakages are inevitable. One solution is to take along an inventory of spare parts. However, this approach is mass intensive and no inventory can be exhaustive. The alternative is to “take the tools, not the parts.” Advances in rapid prototyping have produced commercially available machines that can produce parts that have a complicated, three-dimensional nature, given power and an electronic file describing the object. The downside of this approach is a higher power requirement. However, if a power-rich approach is part of the architecture, then this alternative is readily accommodated. An assessment of the potential benefits of rapid prototyping of spare parts needs to be included. Studies of trade-offs may provide an optimal solution. Robotic precursor missions to the Moon prior to human landing. Every kilogram of equipment taken to the lunar surface needs to perform for as long as practical while remaining cost-effective. Although the surface conditions can be closely approximated, no simulation can totally mimic the lunar environment. NASA has no current plans to fund an ISRU precursor demonstration; a precursor mission is dependent on an opportunity with one of NASA’s international partners. Alignment with the Vision for Space Exploration: Green Flag The benefits of the ISRU project for both lunar and Mars exploration are well aligned with the goals of the VSE because this technology can dramatically improve the probability of success in meeting the goals for the lunar and Mars missions. The performance benefit of consumables production on the surface allows a science mission in support of the VSE, not just a quick visit. This research project is unique in the world; no other country at present is seriously developing technologies for ISRU. 20 FISSION SURFACE POWER Objective The objective of the ETDP’s Fission Surface Power (FSP) systems project is to develop an FSP system concept that meets surface power requirements, including the periodic recharging of long-duration portable power sources, at reasonable cost with added benefits over the competitive options. To achieve this objective, NASA has organized a joint NASA and DOE team with representatives from NASA’s Glenn Research Center and Marshall Space Flight Center and DOE’s Idaho National Laboratory, Los Alamos National Laboratory, Oak Ridge National Laboratory, and Sandia National Laboratories. In addition, NASA and DOE have involved industrial teams (e.g., Lockheed-Martin and Pratt & Whitney Rocketdyne) and universities in their studies. The initial focus is on providing a 40-kWe nuclear reactor that could power the proposed Shackleton lunar base and provide the added assurance that such a concept could also be used to power a Mars base. The FSP concept presented was described as at a fairly high TRL, which should reduce both the risk and the cost of developing it.
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Review of NASA’s Exploration Technology Development Program: An Interim Report Status If NASA chooses the FSP as its source of electrical power, then the 40-kWe reactor would be designed to operate for at least 8 years at full power within the mass envelope of the Lunar Surface Access Module and could be used at any location on the Moon. Shielding would be provided by the lunar regolith, i.e., as a result of inserting the reactor in a pre-excavated hole and adding upper plug shielding. The reactor would use uranium dioxide (UO2) fuel and Type 316 stainless steel (SS-316) cladding. Both of these materials have been used in terrestrial reactors. The coolant would be a eutectic of sodium and potassium referred to as “NaK.” This coolant has also been used in terrestrial reactors. For the power conversion system, NASA is proposing to use Stirling power conversion, a technology that NASA has been studying in various technological forms for about 20 years. A backup power conversion option is Brayton technology, building on what was done for the proposed Jupiter Icy Moons Orbiter nuclear power system. Ratings Quality: Green Historically, NASA and DOE have been the leaders in space nuclear power, and that continues to be the case now. There is no evidence that international entities will enter this field within the schedule envisioned for the VSE, although it is pointed out that the Russians have space nuclear reactor capability. Given that this program is driven by the VSE and therefore concentrates on relatively small-scale reactors in which there is no obvious commercial interest, it is very doubtful that any non-NASA, non-DOE sources will develop a competing or alternative technology that NASA could use for this purpose. There is a team in place composed of NASA and DOE personnel who are working well together, and some of the members have worked on previous space nuclear reactor programs (e.g., SP-100 and JIMO) and thus have experience in the field. The members do not have flight experience because the United States has not flown a fission reactor since 1965, nor do they have experience in burying fission reactors on the Moon; both skills will have to be learned. Effectiveness in Developing and Transitioning: Yellow Flag The FSP technology roadmap envisions an interactive combination of concept definition and risk reduction work through FY 2012 to support awarding of a prime contract in FY 2013 to produce the development test models, engineering models, and flight models. Under this plan, NASA estimates that TRL 6 would be achieved by 2012. The proposed budget profile presents a large programmatic risk. Jumping from $14 million in 2013 to over $200 million/yr in the subsequent years will strain U.S. industrial capabilities. Industry participation in the 2008-2013 time frame would serve to get industry vested in the project. However, the industrial base for nuclear engineering technologies has shrunk in the last 20 years due to the standstill in commercial reactor construction, and there is a concern that, also given an aging workforce, the industry may not be able to react to a sudden call in a few years to a NASA program just as the licensing of new commercial reactors appears to be on a significant increase. In addition, the committee is concerned about the potential consequences resulting from setting 2013 as the proposed date of decision. Other ETDP projects such as ISRU, dust mitigation, and cryogenic fluid management state that they would change their tasks if they knew they would have access to 40 kWe rather than the use of two or three modules of 6-10 kWe per module currently envisioned with a photovoltaic system. To wait until 2013 to make this decision may limit much of their work over the next few years.
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Review of NASA’s Exploration Technology Development Program: An Interim Report A potential gap in the FSP technology development effort is the absence of a full-up ground test unit that incorporates both the nuclear reactor and the power conversion subsystem in a single, integrated unit that could be tested prior to use in an actual mission in a representative environment. While the NASA/DOE team considered this option and concluded that it can demonstrate readiness through a combination of component, subsystem, nonnuclear, and zero-power nuclear testing, there is a concern borne out by other space projects that having a full-up ground test unit can allow the identification and correction of unforeseen problems (the “unknown unknowns”) and provide confidence that the flight unit will perform as designed. Before a commitment is made to the proposed program of no full-up ground test unit, an independent, detailed technical and programmatic review of the project’s proposal by NASA and the DOE would be beneficial. The FSP project plan, as presented, lacked detailed specificity on the organizational interactions, e.g., the structure of the DOE interrelationships. No lead DOE laboratory was identified. The details of NASA’s interaction with the DOE laboratories were not specified. Alignment with the Vision for Space Exploration: Gold Star The availability of 40 kWe of continuous electrical power during the day and night would have major architectural benefits. Technologists working to develop ISRU, dust mitigation, and cryogenic fluid management would benefit greatly from the availability of increased electrical power. Obviously, the life support system and science instruments would benefit from more power. This is a critical enabling technology for human exploration of the Moon and Mars. 21 SUPPORTABILITY Objective The basic concept of supportability is to minimize the logistics footprint required to support exploration missions. Strategies to achieve this objective include broad implementation of commonality and standardization at all hardware levels and across all systems (interoperability repair of failed hardware at the lowest possible hardware level, manufacture of structural and mechanical replacement components as needed, and logistics). The Supportability technology development project consists of three tasks: Component Level Electronic Assembly and Repair, which is further divided into manual repair, semi-automated diagnostics, and functional test and automated repair; Minimally Intrusive Repair, Detection and Self-Healing Systems; and Smart Coatings. The goals of these tasks are to decrease reliance on terrestrial support, reduce the mass volume of logistics spares, increase the operational availability of spacecraft systems, and provide robust damage-tolerant systems. The benefits of supportability are such that all three tasks presented were ranked highly by the Constellation program based on their impact on life cycle costs. The selected tasks are already defined as either high ranking or as lunar-critical-path items. Status The Supportability team appears to have the expertise and innovation to complete the tasks as defined; however, this project seems to be a small subset of the tasks required for a general implementation of supportability. This project needs to be expanded as it appears to be implemented based on specific technology requests as opposed to a systematic look at all the supportability requirements and options. This presents a risk that supportability will be available in some areas but not in others.
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Review of NASA’s Exploration Technology Development Program: An Interim Report There is a significant risk that advancing technology will eclipse many aspects of existing avionics systems. A task needs to be added to assess the impact of technology development on projected supportability options. Technologies developing on tracks parallel to electronics for sensing and control include bacteriorhodopsin-based state machines; artificial opal-based state machines; wavelength-routed, fault-tolerant, all-optical networks; optical sensors (all implemented in circuit or free-space radio frequency or infrared-based wireless networks); and living biological sensing systems based on “smart yeast.” These technologies reduce the need for a substantial amount of electronics and code, eliminate the need for copper wire carrying telemetry in many cases, and are so low in mass that they allow for massive redundancy, thus reducing the need for repair. Other examples are holographic crystal-based memories and optical correlators for information processing (which would include integrated vehicle health management, including diagnostics and prognostics); standardized micro-controllers; polymer-based electronics; and displays that can be manufactured with bubble jet printers. In addition to developing chemically responsive insulation polymers that heal themselves under a variety of conditions, approaches for detecting and repairing age-related damage to wiring should address techniques that can be carried out autonomously by micro-robotics capable of locating faults by chemical detection of self-healed or degraded materials and by the presence and direction of electric fields or the direction of magnetic fields (stored in particles contained in the insulation) generated by a fault. These types of systems could spin polymers to repair insulation and install anti-chafing at the damage site and similar sites to prevent recurrence. Ratings Quality: Green Flag The various tasks under the Supportability project appear to have high quality in both development path layout and ability of participants to complete the projects. The TRLs of the projects are in the 2 range, with some concepts advancing to TRL 4 in 2008. This project has many affiliated universities and industries. The effort would likely benefit from involvement of more universities examining competing concepts. Effectiveness in Developing and Transitioning: Yellow Flag The current level of effort limits the effectiveness of the Supportability project in achieving its goals. The risks are very high because the technology is at a low TRL, is specific to particular technologies, and lacks generality. Technology gaps identified are as follows: Component Level Electronic Assembly and Repair Conformal coating on electronic circuit cards is not conducive to repair or diagnostics. Technology development is required to produce systems capable of removing and restoring coatings of arbitrary thickness or sensing parameters without disturbing the coatings. Diagnostics requires multiple types of complex instruments. Methods are required to sense and evaluate signals in such a way that the required information can be generated with a single analysis instrument. An alternative approach is to reduce the mass, power, and volume of the required diagnostic tools to an acceptable value. Minimally Intrusive Repair, Detection, and Self-Healing Systems
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Review of NASA’s Exploration Technology Development Program: An Interim Report Prototype conductive polymeric outer insulation layers are too dissipative to be used for detecting faults due to insulation failure. This is a materials issue that currently prevents fault detection via wire insulation from becoming a reality. The self-repair process mediated with chemically reactive microsphere fill-in wire insulation generates by-products that can accelerate the degradation of wire insulation. This is another materials problem that will require finding a reactive system that produces insulating polymers with the correct properties with no problematic by-products. Smart Coatings Remote detection of corrosion. A system is required to nondestructively detect corrosion in hidden places without removal of paint or thermo control/protection systems that may cover the structure. This will require the use of chemical indicators, release of detectable volatiles, or the exploitation of physical effects such as surface acoustic waves to detect the corrosion. Failure to achieve this aim might result in increased program costs; baselining will need to be carried out to verify this point. Stabilization of flame deflector refractory coatings. The current means of anchoring the refractory material to the flame deflectors has a poor performance record. Failure to develop more effective methods and materials will result in increased risks to personnel and equipment and costs to the program. Alignment with the Vision for Space Exploration: Green Flag The performance benefits from self-sufficiency with respect to maintainability and streamlined logistics will enable cost reductions in implementing both lunar and Mars exploration, and thus this work is well aligned with the VSE. 22 HUMAN-ROBOTIC SYSTEMS/ANALOGS Objective The main effort concentrates on reconfigurable and long-range robot vehicles and supporting technologies. This approach enables in situ resource utilization (unloading the lander; assembly, maintenance, and transfer of a lunar base; longer-range and longer-duration basic science experiments) and augments astronaut safety and productivity. The plan is novel (is unlike that used for Apollo) and aggressive (based around technologies not yet flown) but appears feasible, and if successful will not only enable the current Constellation program architecture but also significantly enhance it. Status The basic plan to coordinate the effort appears solid and seems to include all relevant expertise within NASA. The team has some outstanding individual members and groups, particularly at JSC in systems design and integration, at JPL in rover and vehicle development, and at ARC in software. It is not clear, however, that the members at the other NASA field centers in the plan add significantly to the effort. The NASA team stated that the technology is generally at TRL 4; it needs to be advanced to TRL 6. NASA appears to be planning to conduct almost all the effort in-house. By ignoring external expertise, this approach may not produce the highest-quality or even the best-value product possible. The claim is that the team could not be strengthened without additional funding. However, it seems likely that
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Review of NASA’s Exploration Technology Development Program: An Interim Report replacement of several existing components of the current team by external experts might well produce significantly superior results. Ratings Quality: Green Flag In contrast to some other ETDP task areas, NASA is not the international benchmark in this technical area (robotics and human-machine systems). While the NASA team has some outstanding individuals and the project leads are aware of the wider national and international research community, apart from a few small existing grants, it appears that the strategy is to “go it alone.” While NASA is the clear world leader in planetary rovers and extraterrestrial vehicles and some aspects of time-delayed teleoperation, the leading expertise in many of the other key technologies in this task lies outside NASA. It appears likely that non-NASA sources would produce results at least as effective for other important aspects of the work, for example, planning, sensing, operator interfaces, and control. Some relevant U.S. benchmark efforts are conducted at Carnegie Mellon University, Stanford University, the University of Washington, and Vanderbilt University. However, the committee believes that the group can achieve the objectives, and it is a matter of how well or how cost-effectively it would be done. Effectiveness in Developing and Transitioning: Yellow Flag Facilities to mature some (ground-based) aspects of the human-robot systems technology are in place. However, NASA will need to provide significant additional resources if the developed technologies are to be tested in relevant environments, including in-orbit and realistic lunar environment testing. NASA seeks to accomplish transitioning of the technology through analog testing, which integrates testing of multiple subsystems among nine potential test sites. Analog field testing is designed to help identify technology gaps for future systems and develop requirements for operational concepts. Detailed planning is needed to ensure that the 5-year notional plan for RAT (research and technology) studies can enable the human-robot supporting technologies to achieve the desired TRLs and that these studies are relevant for all lunar considerations. (RAT is a combined group formed of inter-NASA center personnel collaborating with representatives of industry and academia to conduct remote field exercises.) The main risks for meeting the current plan and schedule goals appear to be budgetary. This effort seems underfunded for the next 5 years or so. While the basic technology concept appears solid, significant costs are likely to arise in development and (particularly) testing. If NASA does not make the commitment to meet these costs, the deadlines will almost certainly slip, and the effort could fail. Alignment with the Vision for Space Exploration: Green Flag The human-robot systems technology has significant architectural benefits. It enables lower costs by utilizing a significantly higher percentage of lander mass in in situ operations (more of the landed mass is part of the lunar vehicles). It enables higher payload capability and lower operational risks (the lunar vehicles will robotically handle, transport, and assemble high-mass and high-risk components). The technology has significant performance benefits. It enables longer and more distant (from lunar base) missions (autonomously and with astronauts). It offers the possibility of transporting the entire lunar operation across the lunar surface, to access significantly more sites of scientific interest. The technology is generally robust to changes to the architecture (for example, exploration missions to Mars). The main issue preventing direct transfer to Mars missions is the longer time delay, which would prevent the proposed ground-based control mode for some of the robot operations.
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Review of NASA’s Exploration Technology Development Program: An Interim Report TABLE 1-1 Summary of the Committee’s Ratings of Each ETDP Project with Regard to Quality, Effectiveness in Developing and Transitioning Technology, and Alignment with the Vision for Space Exploration NOTE: A few projects were given two ratings because of major distinctions between elements within a given project.