C.J. Wohl, B.M. Widener, A. Hatfield, K.P. Wilding, A.M. Howard, I. Guven, S.E. Prameela, J.K. Saito, C.C. Schappi, K.L. Gordon, V.L. Wiesner
NASA Langley Research Center,
United States
Summary:
Through the Artemis program, NASA intends to develop a sustainable human foothold on the Moon, ultimately paving the way for crewed exploration of Mars.¹ The Moon's hostile environment poses numerous obstacles, including exposure to radiation, temperature extremes, micrometeoroid threats, and particularly the persistent problem of lunar dust.² Lunar dust impacts nearly every aspect of surface operations through adhesion and abrasion mechanisms, with contamination from anthropogenic activities (landing, rovers) far outweighing natural phenomena.³ Multiple adhesion pathways contribute to surface contamination in the lunar environment,⁴ including van der Waals forces, electrostatic forces, chemical reaction, and magnetic forces from elemental iron deposits.⁵ Sharp asperities from micrometeoroid bombardment and atmospheric absence increase interaction potential and enable mechanical interlocking.⁶ Low cohesion between dust particles⁷ exacerbates these challenges, as minimal interaction potential between dust and nearby surfaces overcomes particle cohesion, causing contamination. Lunar dust adhesion mitigation technologies can be categorized as either active, requiring external energy, or passive, relying on intrinsic material properties.5 Ultrasonic and electrodynamic technologies have been developed to the highest technology readiness level for active approaches. Passive strategies primarily focus on surface chemistry and topography modifications. At NASA Langley Research Center, approaches include surface migration agents to reduce surface energy, topographical modification using laser ablation patterning, and tailored surface conductivity to reduce intrinsic adhesion force. Performance has been evaluated using custom-built ultrasonic and centrifuge instruments. Plume-surface interactions from lunar landers can propel micrometer-sized particles at velocities up to 1000 m s-1.8 These particles pose risks to landers, habitats and infrastructure, leading to erosion, degradation, and reduced component lifespan. A panel recovered from Surveyor III was determined to have been severely abraded because of lunar dust displaced from the Apollo 12 lunar module that landed 160 m away.9 The performance of metallic surfaces has been evaluated via high velocity single particle impact using the laser-induced project impact test (LIPIT) facility at the University of Utah. Peridynamics modeling, a form of continuum mechanics that uses a nonlocal approach enabling greater simulation capabilities of crack initiation and fracture, has also been utilized to gain greater insight into material response during impact events.10 Lunar dust contamination challenges extend to power generation systems and moving equipment.11 Cables, rotation stages, and other mechanisms may experience limited range of motion and reduced lifetime due to dust infiltration. NASA Langley Research Center has evaluated traditional aerospace alloys, softgoods, wear resistant ceramics, and several polymer and polymer composite materials.12 Test methods have included traditional techniques like Taber abrasion testing, as well as designed test configurations developed in the DUSTE (dust, ultraviolet radiation, and space thermal environmental) chamber that reproduce mechanism functions in operational environment. Beyond laboratory experiments, several flight experiments have been conducted. Materials were exposed to the low Earth orbit environment on the Materials International Space Station Experiment (MISSE) and to the lunar surface environment through the Aegis Aerospace Regolith Adherence Characterization (RAC) payload13 and the Honeybee Robotics Lunar PlanetVac (LPV) payload.14 Determining lunar dust's impact on surface exploration and habitation requires comprehensive experimental and computational capabilities combined with lessons learned from initial lunar activities. Identifying the greatest environmental challenges and developing mitigation technologies provides the clearest path toward successfully, expeditiously, and efficaciously completing NASA's mission. This presentation will discuss ongoing efforts at NASA Langley Research Center and collaborator contributions to these critical objectives. References 1. Moon to Mars Architecture Executive Overview. National Aeronautics and Space Administration, 2024. https://www.nasa.gov/wp-content/uploads/2024/12/2024-architecture-executive-overview.pdf?emrc=4a55b3 2. Heiken, G.H.; Vaniman, D.T.; and French, B.M., eds.: Lunar Sourcebook: A User’s Guide to the Moon, Cambridge University Press, New York, NY, 1991. 3. Wohl, C.J., et al.: Lunar Dust Considerations for Vertical Solar Arrays Volume 1: Lunar Environment and Dust Interactions. NASA/TM—2024-3496, 2024. https://ntrs.nasa.gov 4. Abel, P.B., et al.: Lunar Dust Mitigation: A Guide and a Reference: First Edition (2021). NASA/TP-20220018746, 2022. https://ntrs.nasa.gov 5. Zanon, P., Dunn, M., Brooks, G.: Current Lunar Dust Mitigation Techniques and Future Directions, Acta Astronautica, vol. 213, 2023, pp. 627-644. 6. Morris, R.V.: Handbook of Lunar Soils. NASA Lyndon B. Johnson Space Center, 1983. 7. Jaffe, L.D.: Lunar Surface Strength. Icarus, vol. 6, nos. 1–3, 1967, pp. 75–91. 8. Morris, A.B., et al.: Lunar Dust Transport Resulting From Single- and Four-Engine Plume Impingement. AIAA J., vol. 54, no. 4, 2016, pp. 1339–1349. 9. Cour-Palais, B.G., et al.: Results of Examination of the Returned Surveyor 3 Samples for Particulate Impacts. Analysis of Surveyor 3 Material and Photographs Returned by Apollo 12, National Aeronautics and Space Administration, 1972, pp. 158–167. https://ntrs.nasa.gov 10. Silling, S.A. and Lehoucq, R.B.: Peridynamics Theory of Solid Mechanics, Advances in Applied Mechanics, 44, 2010, pp. 73-168. 11. Levine, J. S., ed.: The Impact of Lunar Dust on Human Exploration. Cambridge Scholars Publishing, Newcastle, England, 2021. 12. Wiesner, V.L., et al.: Testbed for Lunar Extreme Environment Wear Tolerant Applications. 47th Aerosppace Mechanisms Symposium, Virginia Beach, VA, United States of America, May 15-17, 2024. 13. Das, L., et al.: Surface Engineering and Selection of Materials for Lunar Regolith Adherence Characterization. Acta Astronautica, vol. 219, 2024, pp. 532-541. 14. Zacny, K., et al.: PlanetVac: Regolith Mining Systems for CLPS Blue Ghost Lander. 55th Lunar Planetary and Science Conference (LPSC), The Woodlands, Texas, United States of America, March 11-15, 2024.