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NASA NTRS2023

B 4 C-Al Metal Matrix Composites for Extreme Space Environments

Extreme space environments such as space vacuum, radiation, thermal extremes and cycles, jagged lunar dust, microgravity, micrometeoroids and orbit debris (MMOD), thrust plume ejecta, and their synergistically-adverse effects are difficult challenges for safe and sustainable space exploration to outer planets and satellites. Prolonged space radiation exposure embrittles materials and structures and abrasive jagged dust particles aggressively wear and erode moving parts leading to premature failure. To counter or even alleviate such potential failures, robust and exceptional materials are needed to make NASA missions including Artemis program sustainable with minimum service and repair needs. This study reports that boron-containing inclusion, B 4 C, can improve wear resistance and radiation shielding/resistance of aluminum alloy (Al6061) significantly to extend the service life in extreme space environments. With increasing B 4 C inclusions, the tensile strength increased up to 20 vol% at both room temperature and an elevated temperature (200˚C) while thermal conductivity decreased gradually as a function of B 4 C concentration. The neutron shielding effectiveness increased more than 110 times when 50 vol% B 4 C is incorporated in Al6061 when compared with the pristine Al6061. The shielding effectiveness under galactic cosmic rays (GCR) and solar particle events (SPE) was also studied computationally using on-line tool for the assessment of radiation in space (OLTARIS). By adding B 4 C, the adverse effect caused by secondary radiation through the Al6061 matrix was effectively suppressed to improve the shielding effectiveness against GCR and SPE. The presence of boron in B 4 C was the main reason for the enhanced radiation shielding capability against neutron, GCR, and SPE environments.

Sang-Hyon Chu↗

NASA NTRSDate not supplied

Lunar Dust and Dust Mitigation Testing

Lunar dust was one of the most persistent problems for the Apollo astronauts due to its’ abrasiveness and strong adherence to surfaces. With the Artemis program, NASA is planning longer stays on the lunar surface, with more activities that have the potential to put the astronauts and equipment in contact with greater quantities of lunar dust. The success of these missions will depend on our understanding of material interactions with lunar dust and the development of ways to mitigate dust effects. This is particularly true in cases where exposure to dust will lead to failure of components, unacceptable loss of power or thermal control, unacceptable loss of visibility, or health issues. Lunar dust, issues with lunar dust, and ground testing with lunar simulant will be discussed as well as the development of and planned flight testing of optically transparent work function matching coatings to reduce adhesion of dust on the lunar surface.

Lunar dust↗

NASA NTRSDate not supplied

Establishing Standardized Test Methods for Evaluating Space Suit Gloves

The Artemis space suit glove environmental protection garment (EPG) will be the first line of protection used to shield the crewmember’s hands from the environments encountered during extravehicular activity (EVA). As the Artemis missions will include more extreme environments than those experienced on the International Space Station, development, verification, and validation of gloves poses three key challenges. First, there are no standardized tests defined to evaluate the durability of space suit gloves for the extreme lunar environments, particularly the permanently shadowed regions. Second, there is insufficient data on state-of-the-art glove performance in a lunar environment from which to compare new designs. Third, current ISS glove Thermal Micrometeoroid Garment (TMG) fabrics are unlikely to be sufficient to meet Lunar requirements. It is therefore necessary to define tests to evaluate if gloves can meet new, challenging requirements. This paper focuses on the development of a test procedure to characterize lunar EVA glove fabrics using ASTM standardized test methods and the design and validation of a new standardized test procedure for comparing abrasion resistance between fabrics in lunar-like conditions. The results of testing on twelve candidate EVA glove fabrics are presented.

Robert J. Jones↗

NASA NTRSDate not supplied

Plume-surface interaction testing for crewed lunar lander risk reduction

Spacecraft conducting propulsive near-surface operations such as landing or initial ascent must consider potential hazards caused by rocket exhaust interacting with planetary regolith. Gas-granular interactions can erode the surface and eject material, altering the landing site, obscuring views of the surface, and creating abrasion or impact risks. The next generation of lunar landers under development for NASA’s Human Landing System program will push us outside Apollo flight experience for plume-surface interaction. Strategic knowledge gaps and poorly constrained flight data inhibit our ability to accurately and precisely predict the plume-surface interaction environment for a given flight vehicle. We present an overview of a lunar relevant, supersonic plume-surface interaction test that will be conducted in 2024 to improve our understanding of lunar PSI and reduce associated risks to the HLS program.

Wesley A. Chambers↗

NASA NTRSDate not supplied

Review of Lunar Dust Computational Fluid Dynamic Model Development, Applications, and Validation for Habitable Volumes

As humans look to return to the lunar surface, Environmental Control and Life Support Systems (ECLSS) must be able to control lunar dust concentrations to minimize impacts to crew health and equipment within the cabin environment. Lunar dust is abrasive and can deteriorate the performance of spacesuits and equipment inside of habitable volumes. Development and validation of computational fluid dynamic (CFD) models assist in understanding the behavior of lunar dust and aids in design of ECLS systems. Previous analysis efforts include modeling the effect of lunar dust on the crew's health, devices to filter out lunar dust from ventilation systems, and module ventilation to predict where lunar dust would settle in modules. This paper is a literature review of the modeling and testing techniques currently used in industry to analyze how lunar dust will affect ECLSS functionality. Details about lunar dust material properties and knowledge gaps are also examined.

Monica Mah↗

NASA NTRSDate not supplied

Additive Manufacture of Novel Tungsten Wicking and Heat Transfer Structures

Additive manufacturing (AM) is utilized for fabricating complex geometries from refractory metals, such as tungsten and molybdenum. In this study, plates with ultra-fine and fine lattice structures were manufactured from tungsten to demonstrate printability and the component fabrication advantages of AM. Previous work was completed on individual tungsten lattice structures; this work demonstrates the advantages of printing these structures on tubing and first-wall materials. Initial work using stainless steel demonstrated increased heat transfer properties promoted by these lattice structures. Applications for these structures include wicking structures, heat pipes, and first-wall materials in fusion devices. A major advantage of these designs is the capability to produce a monolithic component with tailored heat transfer and wicking properties. This research helps promote the ability to use liquid lithium in fusion devices since these lattice structures manufactured from tungsten could act as a high temperature first-wall or divertor material and as a wicking structure for liquid lithium. Different lattice structures with varying unit cell sizes and strut thicknesses were printed and the effects of these structures on heat transfer properties were measured. Abrasion resistance of these structures was also investigated. This presentation will discuss the results of these experiments and their implications related to heat transfer applications. This work will help inform the development and implementation of complex geometries made from tungsten for future heat pipe and fusion first-wall or divertor component designs.

Carly J. Romnes↗

NASA NTRS2023

Overview and Results From the Mars 2020 Perseverance Rover's First Science Campaign on the Jezero Crater Floor

The Mars 2020 Perseverance rover landed in Jezero crater on 18 February 2021. After a 100-sol period of commissioning and the Ingenuity Helicopter technology demonstration, Perseverance began its first science campaign to explore the enigmatic Jezero crater floor, whose igneous or sedimentary origins have been much debated in the scientific community. This paper describes the campaign plan developed to explore the crater floor's Máaz and Séítah formations and summarizes the results of the campaign between sols 100–379. By the end of the campaign, Perseverance had traversed more than 5 km, created seven abrasion patches, and sealed nine samples and a witness tube. Analysis of remote and proximity science observations show that the Máaz and Séítah formations are igneous in origin and composed of five and two geologic members, respectively. The Séítah formation represents the olivine-rich cumulate formed from differentiation of a slowly cooling melt or magma body, and the Máaz formation likely represents a separate series of lava flows emplaced after Séítah. The Máaz and Séítah rocks also preserve evidence of multiple episodes of aqueous alteration in secondary minerals like carbonate, Fe/Mg phyllosilicates, sulfates, and perchlorate, and surficial coatings. Post-emplacement processes tilted the rocks near the Máaz-Séítah contact and substantial erosion modified the crater floor rocks to their present-day expressions. Results from this crater floor campaign, including those obtained upon return of the collected samples, will help to build the geologic history of events that occurred in Jezero crater and provide time constraints on the formation of the Jezero delta.

Mars 2020↗

NASA NTRS2024

Electrodynamic Regolith Conveyor

NASA KSC’s Swamp Works Electrostatics and Surface Physics Laboratory (ESPL) is developing a 4-phase Electrodynamic Regolith Conveyor (ERC) that could convey regolith without the risk of rotating or vibratory actuation, which could jam or require regular maintenance due to the abrasive nature of Lunar regolith. A prototype conveyor has been developed for laboratory testing in a simulated Lunar gravity environment using a suborbital vehicle. The results of the project will be used for development of the 4-phase electrodynamic conveyors for Lunar ISRU, regolith surface sampling, and dust mitigation solutions.

Aaron Olson↗

NASA NTRSDate not supplied

Automation and AI in Space Drilling

Future planetary surface sampling missions, such as delving past the near-surface ice layers on Mars in search of organics and possibly signs of past/extant life, will require lightweight, low-mass planetary drilling and sample handling. Unlike terrestrial drills, these exploration drills must work dry (without drilling muds or gas), blind (no prior local or regional seismic or other surveys), and light (very low downward force or weight on bit, and perhaps 100 W available from solar power or batteries). Given the lightspeed transmission delays to Mars and outward, an exploratory planetary drill cannot be controlled directly from Earth. Drills that penetrate deeper than a few centimeters are likely to get stuck if operated open-loop (the MSL drill only penetrates 5 cm, and the MER Rock Abrasion Tools 5 mm by comparison), so some form of local drill control is required. In the relatively near-term, human crews cannot be presumed to be available for surface instrument teleoperation. Therefore highly automated drill and sample-transfer operations will be required, to explore the subsurface with the ability to safe robotic drilling systems and recover and continue on from the most probable fault conditions. Current automation, scheduling and diagnostic approaches will be discussed that roughly track the actions and roles of humans in terrestrial manual drilling operations.

drill automation↗

NASA NTRSDate not supplied

Space Exploration and the Lunar Surface Environment

People and spacecraft exploring the Moon face unforgiving environments. The lunar surface is covered in fine, abrasive dust churned by meteoroid impacts. Explorers face extreme thermal, radiation, and lighting conditions. Landing spacecraft must account for erosion caused by rocket exhaust, which can be hazardous for the vehicle or nearby assets. This talk will survey these challenges and the work being done to overcome them to achieve mission success.

Wesley A. Chambers↗

NASA NTRSDate not supplied

Anti-Fog Coatings For Spacesuit Helmets

A permanent and robust anti-fog coating was developed that is applied to the interior of polycarbonate spacesuit helmets. The coating is a mechanically resilient and permanent superhydrophilic (SHPL) layer produced by a two-step process consisting of a plasma processing pre-etch followed by the deposition of an optically transparent Diamond Like Carbon (DLC) coating to achieve an anti-fog, SHPL-DLC layer with Water Contact Angle (WCA) < 10°. The all-dry vacuum process consists of an oxygen plasma etching to engineer the surface of the polycarbonate, creating a well-controlled nanotextured morphology, which is key to the superhydrophilic properties, followed by vacuum deposited Plasma Enhanced Chemical Vapor Deposition (PECVD) DLC coating with high surface energy. The process is carried out at low temperatures compatible with polycarbonate materials and the two steps are performed back-to-back without breaking vacuum between steps. The process is readily scalable and compatible with large scale production volumes. The SHPL-DLC coating was tested for > 200 hours exposure using a breath simulator with no detrimental effect on the coating performance. The coating was also tested for exposure to cleaning fluids, IPA chemical exposure, adhesion testing per ASTM D3359, and abrasion resistance per MIL-E-12397 with no detrimental effects.

Spacesuit↗

NASA NTRS2024

Durable Antifog Coatings for Spacesuit Helmets

Maintaining a high level of visibility through the helmet of NASA Extravehicular Mobility Unit (EMU) is very difficult under inclement operational conditions. The interior of the helmet bubble will fog up in a high humidity / cold environment with high work rate breathing for extravehicular activity (EVA) that can last up to 8 hours. Currently used wipe on antifog solutions have problems with i) durability, requiring reapplication for every EVA, ii) can potentially get in the astronaut’s eye, impairing their vision, and iii) bottles of solution are a consumable that need to be continuously restocked. Luna Labs has developed a durable, transparent coating that is projected to maintain optical and antifogging properties for the lifetime of the equipment. Luna Labs has leveraged our established Gentoo™ sol-gel coating platform to create a robust, transparent, long-lasting, and antifogging coating. Additionally, the proposed sol-gel coating is thin (2-8 µm), low cost (cents/ft 2 ), and easy to apply while providing excellent abrasion durability and antifogging properties. Luna Labs has produced a coating formulation to possess antifogging properties so that moist air will wet out, forming a microscopically thin sheet of water that does not scatter light. A custom superhydrophilic additive which crosslinks into the durable coating matrix provides superb antifogging properties. This non-scratch transparent coating that will provide continuous antifogging efficacy for >8 hours and environmental durability to last the lifetime of coated component. This technology is relevant to NASA spacesuit applications, as well as for automobiles, aircraft, eyewear, SCUBA masks or any other applications that require transparent antifogging properties.

Spacesuit↗

NASA NTRSDate not supplied

Durable Anti-Reflective and Anti-Fog Coatings Produced by Aerosol Impact Driven Assembly

The Exploration Extravehicular Mobility Unit’s (xEMU) helmet is a complex assembly designed to accomplish several tasks to protect and enable astronauts. In addition to maintaining a suitable environment for the wearer, it must also allow for appropriate mobility and provide a wide and undistorted view of the surroundings. A critical component of the helmet’s optical system is the anti-fog coating. While previous versions of the anti-fog coating have provided suitable anti-fog performance, they have been difficult to apply, lacked mechanical or chemical durability, or resulted in unanticipated failures (e.g., outgassing of eye-irritating materials during use). This work describes the use of a new coating technology, aerosol impact-driven assembly (AIDA), to develop a next-generation permanent anti-fog coating for the xEMU helmet. AIDA’s unique ability to tune both the refractive index and surface roughness of films was used to deposit a thin, transparent (>85% transmittance of visible light), and hydrophilic (contact angle <10°) anti-fog coating. The coating’s abrasion resistance and chemical resistance was evaluated and it was found that the coating maintained both its anti-fog and anti-reflective functionally. Finally, the scalability of the process was demonstrated by successfully coating the polycarbonate blanks used to form the helmet’s bubble.

Spacesuit↗

NASA NTRSDate not supplied

Thermal Impact of Lunar Dust on Rovers

Experience and ground tests have shown that lunar dust coverage can severely degrade thermal system performance, and with the push to go back to the Moon for longer than a few days, lunar dust is being recognized as a significant technical challenge. The Lunar Terrain Vehicle (LTV) and Pressurized Rover (PR) will be operating on the lunar surface for long durations and roving at high speeds with interaction with astronauts and other robotics, which will cause dust to transfer to the vehicle, potentially to critical thermal surfaces. Dust coverage results in a change of overall optical properties, increased resistance to heat rejection due to the insulating effect of a dust layer, and even abrasion to thermal surfaces and soft goods. This paper provides an overview of what is currently known and unknown about what will happen to thermal surfaces exposed to dust on the Lunar South Pole, some dust mitigation options and testing guidance, and what resources can be used to help overcome this problem.

Lunar dust↗

NASA NTRSDate not supplied

Thermal Impacts of Lunar Dust For Rovers

Lunar dust↗

NASA NTRS2024

Wear and Neutron Shielding Resilience of Titanium-Hexagonal Boron Nitride Coatings Against Extreme Lunar Radiation and Thermal Cycles

Ti6Al4V and Al6061 are aerospace alloys used in lunar structural components and rovers owing to their high specific strength. However, they deteriorate rapidly when subjected to demanding conditions of the lunar environment, such as extreme thermal cycles, solar particle radiation, and abrasive regolith. Cryo-milled powders were employed to deposit hBN-reinforced protective titanium coatings through plasma spray (atmospheric APS and vacuum-VPS) with 2 and 10 vol% of hBN on Ti6Al4V and Al6061 substrates. These coatings were evaluated for durability under extreme lunar-like conditions, including thermal cycling, electron radiation, and synergistic (electron radiation-thermal cycle) exposure. The coatings exhibited radiation-induced hardening, resulting in a substantial increase in their microhardness ~20–40% compared to virgin condition. Bright-field transmission electron microscopy (TEM) analysis reveals the presence of high dislocation densities, black dot defects, and dislocation clusters, providing evidence of the severe impact of synergistic environmental stresses. Ball-on-disk tribological tests were conducted in the presence of JSC-1 A lunar regolith simulant to evaluate the wear performance of coatings. Compared to conventional Ti6Al4V substrate, 50%, 90%, and 70% reductions in wear volume were observed in the Ti/2 vol% hBN coatings in thermal-only, radiation-only, and synergistic environments. Neutron shielding tests indicate that the synergistic coatings offer higher neutron shielding performance by up to 28% compared to virgin coatings, attributed to improved neutron capture by 10B isotopes. Upon a comprehensive assessment and ranking of multiple coatings under varying conditions, the VPS Ti/2 vol% hBN coating emerges as the top choice for protection against extreme radiation and thermal cycles for future lunar explorations.

Boron nitride↗

NASA NTRS2024

Terrestrial Proving Ground Capabilities Needed for Lunar In Situ Resource Utilization (ISRU) & Construction Concepts of Operation

Incorporating any new technology or system into a human exploration mission or architecture requires development well in advance of the mission to eliminate technology, cost, and schedule risk concerns. It is often stated that technologies need to be at a Technology Readiness Level (TRL) of 6, i.e. ‘system/subsystem model or prototype demonstration in a relevant environment (ground or space)’, by Authority To Proceed (ATP) or by the Preliminary Design Review (PDR) for the mission at the latest. There are two game changing capabilities for sustained human exploration of space that can have a significant effect on the overall exploration architecture and the technologies and systems included in the architecture. The first game changing capability, known as In Situ Resource Utilization (ISRU), involves the search for, acquisition, and processing of resources on the Moon and Mars into mission consumables and usable products, and the second is the ability to utilize space resources in the construction of roads, structures, and surface infrastructure. ISRU and surface construction capabilities have the potential to greatly reduce the cost and risk of human exploration while enabling sustained lunar surface and commercial operations. However, ISRU and surface construction systems are complex and must operate in extremely harsh environments, with abrasive regolith and pervasive dust, for long-periods of time, with potentially limited opportunities for maintenance and repair by humans. The complexity of these capabilities and operations also means that there are a limited number of companies that can design, build, and operate end-to-end systems on their own. The majority of the technologies being developed for these systems are by small companies and at the component or subsystem level. With the overarching strategy of the United States National Aeronautics and Space Administration (NASA) Space Technology Mission Directorate (STMD) to enable industry to implement ISRU and surface infrastructure for Artemis and space commercialization, it is therefore important to establish processes and capabilities to promote and foster collaborations among large and small companies involved in ISRU and surface infrastructure development. For ISRU and infrastructure systems and capabilities to be used in Artemis missions and future commercial lunar surface operations, a coordinated framework with virtual/physical integration and testing locations, or ‘Proving Grounds’, needs to be established and operated on a regular basis and open to all. This paper will discuss the ISRU and surface construction near and long-term concepts of operations, and review operations and lessons-learned from the previous ISRU analog field tests. From this information, requirements and capabilities will be proposed to support and enable the integration and testing of ISRU and construction systems with industry, academia, and international agencies, as well as what facilities and organizations could help establish these Proving Grounds.

ISRU↗

NASA NTRSDate not supplied

Materials for Power Transmission in Extreme Environments

NASA’s goal for a sustained human presence on the Moon and a future Lunar economy requires the development of novel power transmission materials for extreme environments. As an increasing number of public and private entities set their sights towards a future on the Moon, the demand for surface power will dramatically increase – potentially up to megawatt levels. A Lunar economy is envisioned to include a human habitat, manned and unmanned science exploration assets, excavation rovers and systems, and large-scale infrastructure construction such as solar arrays and power grids. A NASA trade study estimated that 1 to 3 km of power transmission lines (1 to 3 KV ac and dc) will be needed over time. Current high power and voltage SOA cables/wire can easily exceed 1 kg/m where mass is not as critical. Connectors, deployment spools and robots further increase the subsystem mass significantly increasing costs. On the other hand, advances in aeronautics provides path towards space missions. The operating environment on the Moon presents substantial risk to safe and reliable power transmission due to space weathering and degradation. These challenges include cosmic and UV radiation, extreme temperatures swings, the electrostatic Lunar exosphere, and the electrostatic and abrasive lunar regolith. The critical need for lightweight, safe and reliable power cables/wires materials is evident. In this presentation, the extreme high altitude and lunar environments and recent materials development from NASA Glenn Research Center’s High Voltage Materials team towards meeting NASA’s objectives and goals for aeronautics and space missions.

Cu/CNT conductors↗