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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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NASA Progress on the Development and Qualification of a 12-kW Hall-Effect, Solar Electric Propulsion Thruster

The National Aeronautics and Space Administration (NASA) continues to evolve the human exploration approach for beyond low-Earth orbit and in a manner involving international, academic, and industry partners. The center of this approach is NASA’s Gateway program that will establish a permanent human presence in lunar orbit for human cislunar science, operations, and lunar surface access to eventually land the next American astronauts on the south pole of the Moon. In support of the effort, NASA’s Space Technology Mission Directorate (STMD) began a project to increase the state of the art for the Hall-Effect Solar Electric Propulsion (SEP) technology. The resulting Advanced Electric Propulsion System (AEPS) project has developed a 12 kW Hall-effect thruster in support of the Gateway program. The project is managed by the NASA Glenn Research Center (GRC), supported by the NASA Jet Propulsion Laboratory (JPL) with development, qualification & flight hardware all supplied by L3 Harris Aerojet Rocketdyne (AR). Development of the 12-kW Hall thruster electric propulsion system began with maturation of the Hall Effect Rocket with Magnetic Shielding (HERMeS) Technology Demonstration Units (TDUs). The technology development was then transitioned to AR via the AEPS contract, which built and tested two Engineering Test Unit (ETU) thrusters and multiple critical components. The project transitioned to the production of the three flight thrusters and entered qualification testing at the component and thruster levels.

Electric Propulsion↗

NASA Progress on the Development and Qualification of a 12-kW Hall-Effect, Solar Electric Propulsion Thruster

The National Aeronautics and Space Administration (NASA) continues to evolve the human exploration approach for beyond low-Earth orbit and in a manner involving international, academic, and industry partners. The center of this approach is NASA’s Gateway program that will establish a permanent human presence in lunar orbit for human cislunar science, operations, and lunar surface access to eventually land the next American astronauts on the south pole of the Moon. In support of the effort, NASA’s Space Technology Mission Directorate (STMD) began a project to increase the state of the art for the Hall-Effect Solar Electric Propulsion (SEP) technology. The resulting Advanced Electric Propulsion System (AEPS) project has developed a 12 kW Hall-effect thruster in support of the Gateway program. The project is managed by the NASA Glenn Research Center (GRC), supported by the NASA Jet Propulsion Laboratory (JPL) with development, qualification & flight hardware all supplied by L3 Harris Aerojet Rocketdyne (AR). Development of the 12-kW Hall thruster electric propulsion system began with maturation of the Hall Effect Rocket with Magnetic Shielding (HERMeS) Technology Demonstration Units (TDUs). The technology development was then transitioned to AR via the AEPS contract, which built and tested two Engineering Test Unit (ETU) thrusters and multiple critical components. The project transitioned to the production of the three flight thrusters and entered qualification testing at the component and thruster levels.

Electric Propulsion↗

Parametric-Based Heat Rejection Trade Study for Lunar and Martian Surface Operations

Establishing and maintaining a sustained presence on the lunar and/or Martian surfaces will require a diverse portfolio of surface elements (e.g., habitation, mobility, power generation, etc.). Many of these systems generate excess heat that must be rejected across a wide range of magnitudes, temperatures, and duty cycles and under variable environmental conditions. To identify the most promising heat rejection approaches for this diverse portfolio, a heat rejection trade study was conducted to evaluate the performance of different technology approaches across a spectrum of surface environments and heat-load requirements. The trade study consisted of three stages: (1) development of a parametric-based modeling framework, (2) creation of a database of heat rejection technologies, surface elements, and environmental conditions for the Moon and Mars, and (3) execution of a quantitative analysis of various heat rejection technologies across different operating conditions and surface elements. The modeling framework is developed in Python and Excel to prioritize small model size and hence low computational cost to enable large parametric sweeps while avoiding the reliance on proprietary software. Individual heat rejection processes are represented as simple Excel models, and a centralized Python script interfaces with the models to coordinate the parametric study. These simple sizing models were developed to take heat load requirements and environmental parameters as inputs and compute mass, power, and volume as outputs. Rather than assess each heat rejection technology separately for each surface element, a unified parametric space was developed to evaluate all technologies across all elements. This parametric space includes factors related to heat load (e.g., magnitude or temperature) and environment (e.g., surface temperature, sky temperature, solar flux). This effort generated a database containing information on over 60 heat rejection technologies and 30 surface elements. For each surface element, the expected heat rejection requirements were documented and analyzed to determine the most common needs shared across all elements. Environmental conditions at various lunar and Martian latitudes were also established for worst-case hot and worst-case cold scenarios. High-fidelity heat rejection models are currently under development. Preliminary trades between heat rejection technologies including radiators, venting technologies, convective coolers, and more have been conducted to identify promising options. This presentation will summarize the preliminary trade results and provide an overview and discussion of the expected heat loads and thermal environments for sustained surface operations on the Moon and Mars.

Heat Rejection↗

Integrated Logistics and Supportability Challenges of Sustained Human Lunar Exploration

NASA’s Artemis program plans to establish a sustained human presence on the lunar surface. The International Space Station other space station programs have demonstrated long-duration human spaceflight operations that reuse infrastructure in Low Earth Orbit, sometimes including long uncrewed “dormant” periods. In contrast, human lunar exploration to date has consisted solely of relatively short sortie missions, rather than a sustained presence. A sustained human outpost on the Moon that can support month-long crewed exploration missions and be reused by multiple crews will be more challenging than past operations, particularly from the perspective of logistics, supportability, and risk. This paper examines the integrated logistics and supportability challenges of sustained human lunar exploration and provides a review of historical spaceflight experience in terms of crewed mission endurance, uncrewed duration, transportation overhead, and access to abort. Planned Artemis Base Camp crewed mission endurance is approximately 2.5 times longer than past lunar surface crewed mission endurance, but similar to average time between resupply for the International Space Station. Sustained human spacecraft have only twice experienced uncrewed durations longer than the planned interval between Artemis Base Camp missions, and Artemis surface assets will face long uncrewed periods more regularly than any past sustained human spacecraft. Transportation of crew and cargo to and from the Moon will be more difficult and time-consuming than transportation to and from Low Earth Orbit, and crew access to abort will be more limited. The implications of Artemis lunar operations for crewed Mars mission planning are also discussed. Historical approaches to risk management—including logistics, supportability, and abort strategies—should be reexamined and re-optimized for this new mission context. Sustained lunar operations will provide a valuable proving ground for testing new approaches to crewed space exploration.

logistics↗

VIPER’s Mass Spectrometer observing lunar operations (MSolo)

The Volatiles Investigating Polar Exploration Rover (VIPER) is a lunar volatiles detection and measurement mission that will land on Mons Mouton near Nobile crater, close to the Moon’s south pole. One of the analytical instruments embedded within the rover is the Mass Spectrometer observing lunar operations (MSolo) instrument. VIPER’s data will ultimately be used to create lunar water resource maps that may enable a sustained presence on the lunar surface. As VIPER navigates several kilometers of terrain, its onboard analytical instrumentation will characterize the presence of volatiles along the traverse path and identify candidate locations for drilling. Upon selection of a drilling site, the rover will position itself and deploy an auguring, percussive drill down to a meter depth. Upon extraction, regolith cuttings captured by the auger are deposited on the surface; an activity that will initiate the release of any volatile gases that are subsequently detected and quantified by MSolo. MSolo is designed to identify low-molecular-weight volatiles (between m/z 1-100) with unit mass resolution. Volatiles of interest include D/H and O18/O16 bearing species, including possible water contained within the lunar regolith. MSolo is a modified, commercial off-the-shelf (COTS) system, meaning the instrument is based on a commercially available unit that has been ruggedized for space applications.

MSolo↗

Integrated Logistics and Supportability Challenges of Sustained Human Lunar Exploration

NASA’s Artemis program plans to establish a sustained human presence on the lunar surface. The International Space Station and other space station programs have demonstrated long-duration human spaceflight operations that reuse infrastructure in Low Earth Orbit, sometimes including long uncrewed “dormant” periods. In contrast, all human exploration beyond Low Earth Orbit to date has consisted solely of relatively short sortie missions, rather than a sustained presence. A sustained human outpost on the Moon that can support month-long crewed exploration missions and be reused by multiple crews will be more challenging than past operations, particularly from the perspective of logistics, supportability, and risk. This paper examines the integrated logistics and supportability challenges of sustained human lunar exploration and provides a review of historical spaceflight experience in terms of crewed mission endurance, uncrewed duration, transportation overhead, and access to abort. Planned Artemis Base Camp crewed mission endurance is approximately 2.5 times longer than past lunar surface crewed mission endurance, but similar to the average time between resupply for the International Space Station. Sustained human spacecraft have only twice experienced uncrewed durations longer than the planned interval between Artemis Base Camp missions, and Artemis surface assets will face long uncrewed periods more regularly than any past sustained human spacecraft. Transportation of crew and cargo to and from the Moon will be more difficult and time-consuming than transportation to and from Low Earth Orbit, and crew access to abort will be more limited. The implications of Artemis lunar operations for crewed Mars mission planning are also discussed. Historical approaches to risk management—including logistics, supportability, and abort strategies—should be reexamined and re-optimized for this new mission context. Sustained lunar operations will provide a valuable proving ground for testing new approaches to crewed space exploration.

logistics↗

The carbon chemistry of the moon.

The analysis of lunar samples has shown that the carbon chemistry of the moon is entirely different from the carbon chemistry of the earth. Lunar carbon chemistry is more closely related to cosmic physics than to conventional organic chemistry. Sources of carbon on the moon are considered, giving attention to meteorites and the solar wind. The approaches used in the analysis of the samples are discussed, taking into account the method of gas chromatography employed and procedures used by bioscience investigators in the study of the lunar fines. The presence of indigenous methane and carbide in the lunar fines was established. Reactions and processes taking place on the lunar surface are discussed.

Eglinton, G.↗

Assessing Utility of Different Orbits for a Lunar PNT Constellation

"As the Artemis program establishes a long-term presence on the lunar surface, lunar surface users will need an accurate source of Position, Navigation, and Timing (PNT). Under the LunaNet framework, NASA has proposed the Lunar Navigation System (LNS), a constellation of satellites in lunar orbit which will broadcast LunaNet’s Augmented Forward Signal (AFS) [1] to the lunar surface. LNS will have the objective of providing user position accuracies of 10 m and timing accuracies of 10 microseconds on the lunar surface and up to 200 km above the surface. Several classes of orbits are possibilities for the LNS constellation, including circular orbits, eccentric orbits, and various families of 3-body orbits. Each of these orbit classes have both advantages and disadvantages in their utility as PNT constellations. In this study we examine a wide variety of potential LNS constellations and evaluate their performance against several metrics, including: a. Dilution of Precision (DOP) performance over the lunar service volume and the South Pole region, during both the constellation buildup and after the constellation is completed. b. Number of satellites required to achieve required DOP performance. c. Relative dynamics of LNS satellites with respect to surface users. d. Signal in space error (SISE) performance, assuming orbit determination that includes the Global Positioning System (GPS), crosslinks, and monitor sites on the surface of the moon. e. Constellation insertion, station keeping, and disposal costs. f. Specific Concept of Operations (CONOPS) and engineering challenges associated with establishing and operating the constellations. (E.g., frequent station keeping, variable signal strength, divergent CONOPS for different planes of the constellation.) The system’s performance is considered both independently and in combination with other proposed systems, such as NASA’s Lunar Communication Relay and Navigation System (LCRNS) and ESA’s Moonlight constellation. The study concludes that a 3-plane Walker constellation at 6 lunar radii (slightly higher than GPS’s 4.2 earth radii from a geometry perspective, but significantly closer in an absolute sense) is a good candidate for the LNS constellation, providing the user with good SISE and DOP performance, while not requiring excessive station keeping or complex CONOPS. However, other viable concepts exist and could be chosen if early South Pole coverage is a driving factor in the system design."

navigation↗

Trace ferric ion in lunar and meteoritic titanaugites.

Evidence for presence of Fe(3+) in lunar rocks is furnished by heating them in air to 200-225 C for two hours. This causes a large decrease in the same charge transfer bands attributed to Fe(3+) that can be enhanced by heating the same rocks in air at 500 C. This is interpreted as evidence that the Fe(3+) was not in equilibrium in the melt but was produced by cosmic radiation subsequent to the rock formation. Possible tetrahedrally coordinated Fe(3+) is present in the meteoritic and lunar augites as suggested by comparison of their spectra to that of terrestrial augite high in Fe(3+). This would have been present in the original melt and is distinct from radiation produced Fe(3+) in the M-sites. The polarized absorption spectra of single crystal pigeonite and augite from rock 12021 before heating, and augite from 12018 after heating are compared to that of meteoritic titanaugite in the Angra dos Reis meteorite and terrestrial titanaugite from Maui, Hawaii. The absorption spectrum of meteoritic hypersthene (Tatahouine) is also included for comparison to the pigeonite.

Cohen, A. J.↗

Long-Range Transhorizon Lunar Surface Radio Wave Propagation in the Presence of a Regolith and a Sparse Exospheric Plasma

Long-range, over-the-horizon (transhorizon) radio wave propagation is considered for the case of the Moon. In the event that relay satellites are not available or otherwise unwarranted for use, transhorizon communication provides for a contingency or backup option for non line-of-sight lunar surface exploration scenarios. Two potential low-frequency propagation mechanisms characteristic of the lunar landscape are the lunar regolith and the photoelectron induced plasma exosphere enveloping the Moon. Although it was hoped that the regolith would provide for a spherical waveguide which could support a trapped surface wave phenomena, it is found that, in most cases, the regolith is deleterious to long range radio wave propagation. However, the presence of the plasma of the lunar exosphere supports wave propagation and, in fact, surpasses the attenuation of the regolith. Given the models of the regolith and exosphere adopted here, it is recommended that a frequency of 1 MHz be considered for low rate data transmission along the lunar surface. It is also recommended that further research be done to capture the descriptive physics of the regolith and the exospheric plasma so that a more complete model can be obtained. This comprehensive theoretical study is based entirely on first principles and the mathematical techniques needed are developed as required; it is self-contained and should not require the use of outside resources for its understanding.

Manning, Robert M.↗

Supervisory On-line Optimal Control of an Electric Power Microgrid Design for Lunar Habitation

The following article describes an optimal control algorithm for the operation and study of an electric microgrid designed to power a lunar habitat. A photovoltaic (PV) generator powers the habitat and the presence of predictable lunar eclipses necessitates a system to prioritize and control loads within the microgrid. The algorithm consists of a reduced order model (ROM) that describes the microgrid, a discretization of the equations that result from the ROM, and an optimization formulation that controls the microgrid’s behavior. In order to validate this approach, the paper presents results from simulation based on lunar eclipse information and a schedule of intended loads.

Joseph Young↗

Degradation of Yttria-Stabilized Zirconia in Molten Regolith Electrolysis Applications

The generation of oxygen from lunar resources is an enabling technology to support a sustained human presence on the lunar surface. Molten regolith electrolysis is a promising process for directly electrolyzing lunar regolith, which is primarily a mixture of oxide minerals. During electrolysis, metallic products (Fe, Si) are formed at the cathode and oxygen is produced at the anode. In order to perform electrolysis, the regolith must be molten to enable ionic transport of metallic cations and oxygen anions, requiring an operating temperature of 1600C. Common refractory oxide materials, such as Al2O3 and MgO, undergo rapid degradation due to the high operating temperature and contact with the corrosive molten regolith. This work investigates yttria-stabilized zirconia (YSZ) for molten regolith electrolysis applications. Corrosion studies are presented to elucidate the degradation mechanism of YSZ powders and crucibles exposed to lunar regolith simulants at 1600C. Two regolith simulants are used to represent regolith from the lunar maria (JSC-1A) and the lunar highlands (LHS-1). Degradation of YSZ in contact with regolith simulants is evaluated using SEM/EDS, XRD, and EBSD. Furthermore, a modified molten regolith electrolysis reactor is presented utilizing YSZ at the anode to enable facile collection of oxygen produced during electrolysis.

Kevin Yu↗

Origin of lunar meteorite ALHA 81005 - Clues from the presence of terrae clasts and a very low-titanium mare basalt clast

Attention is given to the endogenous (or primary) lithologies of the lunar crust that can be inferred from the terrae clasts and to the significance of a fragment of very low titanium (VLT) mare basalt in thin section, ALHA 81005,9. Fragments of the norite and harzburgite have mineral compositions similar to that of ferroan anorthosite, and a clast of ferroan anorthosite has pyroxenes with lower molar Mg/(Mg+Fe) than in known pristine rocks. It is inferred that the Mg-suite protoliths for the clasts of intermediate composition are magnesian troctolites, spinel troctolites, and feldspathic lherzolites. Whereas clasts of these lithologies are not present in ALHA 81005,9, mineral fragments from them are. Based on the molar Mg/(Mg+Fe) ratio and Cr content of its pyroxenes, a single basaltic clast is determined to be of mare origin. The composition of its plagioclase and the molar Ti/(Ti+Cr) ratios of its pyroxenes suggest that the clast is a fragment of VLT mare basalt. It is noted that if this basalt is significantly younger than the last basin-forming impact event, which was approximately 3.9 x 10 to the 9th years ago, then its presence probably constrains the source crater for ALHA 81005 to be within a hundred kilometers of a VLT mare basalt flow.

Treiman, A. H.↗

Lunar Navigation Architecture Design Considerations

The NASA Constellation Program is aiming to establish a long-term presence on the lunar surface. The Constellation elements (Orion, Altair, Earth Departure Stage, and Ares launch vehicles) will require a lunar navigation architecture for navigation state updates during lunar-class missions. Orion in particular has baselined earth-based ground direct tracking as the primary source for much of its absolute navigation needs. However, due to the uncertainty in the lunar navigation architecture, the Orion program has had to make certain assumptions on the capabilities of such architectures in order to adequately scale the vehicle design trade space. The following paper outlines lunar navigation requirements, the Orion program assumptions, and the impacts of these assumptions to the lunar navigation architecture design. The selection of potential sites was based upon geometric baselines, logistical feasibility, redundancy, and abort support capability. Simulated navigation covariances mapped to entry interface flightpath- angle uncertainties were used to evaluate knowledge errors. A minimum ground station architecture was identified consisting of Goldstone, Madrid, Canberra, Santiago, Hartebeeshoek, Dongora, Hawaii, Guam, and Ascension Island (or the geometric equivalent).

D'Souza, Christopher↗

Case Studies for Lunar ISRU Systems Utilizing Polar Water

In-Situ Resource Utilization (ISRU) is key to long term presence at any extraterrestrial destination. Current NASA direction is to achieve a sustainable presence on the lunar surface by 2028. Mission plans currently target the lunar South Pole to leverage the extended periods of solar illumination and allows for potential access to water ice in the permanently shadowed areas around the poles. With water, it is possible to produce both fuel and oxidizer to fully refuel a vehicle. In order to address ISRU infusion into mission planning, a study of an end-to-end ISRU propellant production system was initiated to assess ISRU architectures and obtain mass and power estimates for each. The results of these case studies will be presented.

In situ Resource Utilization↗

Case Study for Lunar ISRU Systems Utilizing Polar Water

In-Situ Resource Utilization (ISRU) is key to long term presence at any extraterrestrial destination. Current NASA direction is to achieve a sustainable presence on the lunar surface by 2028. Mission plans currently target the lunar South Pole to leverage the extended periods of solar illumination and allows for potential access to water ice in the permanently shadowed areas around the poles. With water, it is possible to produce both fuel and oxidizer to fully refuel a vehicle. In order to address ISRU infusion into mission planning, a study of an end-to-end ISRU propellant production system was initiated to assess ISRU architectures and obtain mass and power estimates for each. The results of these case studies will be presented. For this study, The ISRU system architecture involved two sites; the mine site in a shadowed crater where water ice is excavated and extracted from the regolith and the propellant production site at an illuminated ridge where the water is processed into liquefied O2 and H2 propellants. Fixed hardware would be emplaced at each site, with two alternating water tankers to transport water between them. Notional lunar sites were identified for this architecture for baseline environmental parameters. Technology solutions for each subsystem were selected based on those with the highest fidelity models or those that have empirical laboratory data to anchor to. While power needs were identified for each location, a power solution was not prescribed, therefore the masses presented do not include surface power systems. The baseline case in this study assumed that 10 mT of oxygen, along with enough hydrogen to support a propulsion mixture ratio of 6, must be produced in 225 days. Therefore 15 mT of water would need to be collected and processed. The baseline solution resulted in a system mass of5 mT and a total required power of 68kW. The majority of the mass was split between the ridge site system and the two water tankers (2.6 mTand 1.8mTrespectively). The majority of the required power was with three subsystems at approximately 20 kW each: hydrogen liquefaction, electrolysis, and the water extractor subsystem. Trades for four key variables are also presented, namely production rate, water concentration, dry overburden depth, and number of water transport trips. This can be compared to a system that targets oxygen from the minerals in the surface regolith material. A carbothermal reduction reactor system was used for this comparison. The use of direct solar thermal energy to process the regolith and the ease of access of the resource resulted in significantly lower values for the oxygen case: approximately 2.7 mT and 11.8 kW. However, the mass trade would favor the water case over successive missions where the hydrogen up-mass of 2 mT per mission will accrue against the oxygen system.1Aerospace Research Engineer, Chemical and Thermal Propulsion Systems Branch, Senior Member.2Mechanical Engineer, Propulsion and Power Division/Energy Conversion Systems, 2101 Nasa Pkwy/Mailcode EP3 Houston, TX 77058, AIAA member.

Lunar↗

Advances in Molten Oxide Electrolysis for the Production of Oxygen and Metals from Lunar Regolith

As part of an In-Situ Resource Utilization infrastructure to sustain long term-human presence on the lunar surface, the production of oxygen and metals by electrolysis of lunar regolith has been the subject of major scrutiny. There is a reasonably large body of literature characterizing the candidate solvent electrolytes, including ionic liquids, molten salts, fluxed oxides, and pure molten regolith itself. In the light of this information and in consideration of available electrolytic technologies, the authors have determined that direct molten oxide electrolysis at temperatures of approx 1600 C is the most promising avenue for further development. Results from ongoing studies as well as those of previous workers will be presented. Topics include materials selection and testing, electrode stability, gas capture and analysis, and cell operation during feeding and tapping.

Sadoway, Donald R.↗

Thermochemical Interactions Between Yttria-Stabilized Zirconia and Molten Lunar Regolith Simulants

Oxygen produced through in-situ resource utilization (ISRU) is critical to maintaining a permanent human presence on the lunar surface. Molten regolith electrolysis and carbothermal reduction are two promising ISRU techniques for generating oxygen directly from lunar regolith, which is primarily a mixture of oxide minerals; however, both processes require operating temperatures of 1600 C to melt lunar regolith and dissociate the molten oxides. These conditions limit the use of many oxide refractory materials, such as Al2O3 and MgO, due to rapid degradation resulting from reactions between the refractory materials and molten lunar regolith. Yttria-stabilized zirconia (YSZ) is shown here to be a promising refractory oxide to provide containment of molten regolith while demonstrating limited reactivity. This work focuses on corrosion studies of YSZ powders and dense YSZ crucibles in contact with molten lunar maria and highlands regolith simulants at 1600 C. The interactions between YSZ and molten regolith are characterized using SEM/EDS, XRD, and EBSD. A FactSage thermochemical model is created to compare with the experimental results. These combined analyses suggest that lunar maria regolith will degrade YSZ faster than lunar highlands regolith due to the lower viscosity of the maria regolith. The feasibility of long-term molten regolith containment with YSZ is discussed based on the YSZ powder and crucible results.

Kevin Yu↗