Surface Engineered Materials in the Lunar Environment: Results from the Regolith Adherence Characterization (RAC) Payload Mission

NASA’s Artemis program seeks to establish a sustained human presence on the Moon leading ultimately to a crewed mission to Mars. The extreme environment of the lunar surface presents many challenges: lack of atmosphere, radiation exposure, thermal variation, micrometeoroid bombardment, and lunar dust, among others. Adhesion mitigation of lunar dust is difficult to evaluate due to differences in candidate material performance evaluated terrestrially compared to in a lunar environment. Simulation of characteristics of the lunar environment is possible; complete replication on Earth is not as it is difficult to reproduce every environmental aspect, namely differences in gravitational force and vacuum levels. The Aegis Aerospace Regolith Adherence Characterization (RAC) payload mission was designed to evaluate candidate materials exposed to lunar dust on the lunar surface. The RAC payload was delivered to the lunar surface aboard the Firefly Aerospace Blue Ghost lander on March 2, 2025. A sample carrier disc held an array of materials that were exposed to the lunar environment just before landing and for thirteen days after landing. Images were collected of each coupon throughout this period. Researchers from NASA’s Langley Research Center provided three materials for evaluation: a titanium aerospace alloy (Ti-6Al-4V), fluorinated ethylene propylene (FEP, a transparent perfluorinated polymer), and a low creep low relaxation (LCLR) carbon fiber reinforced polymer composite designed for deployable structures. Half of the surface of each coupon was topographically modified using laser ablation patterning to enable evaluation of engineered surfaces. Analysis of the images indicated that significant amounts of lunar dust accumulated on the titanium alloy sample on March 3rd with less accumulation on the FEP sample and no significant accumulation on the composite. It is unclear whether this was the result of differences in lunar dust exposure or adhesion performance. Interestingly, images captured on March 13th indicated complete removal of the lunar dust. Efforts are currently underway to determine the reason the dust was no longer present on the material surfaces.