Simulation of the Lunar Dust Environment
July 31, 2007
Dr. James Gaier received his B.S. in chemistry before teaching high school for three years before continuing his education with a Master’s degree in education from Temple and a PhD from Michigan State in protein crystallography. He began his NASA career in 1983 and has since become a part of the Space Environmental Durability Branch. He worked from 1987-2004 with simulated Martian regolith and now is focusing on lunar dust within the power division. Current work with lunar dust is aimed to make power systems more durable for extended application.
NASA’s vision for space exploration aims to place a human presence on the moon by 2020 for minimum durations beginning at seven to fourteen days and eventually extending to six month stays by 2024. The ORION, ARES, and LSAM vehicles will face several challenges in their design, testing, and eventual use including: vacuum, thermal cycling, micrometeoroids, chemical/biological issues, radiation, and lunar dust.
Lunar regolith contaminates exposed surfaces, clogs mechanical parts, compromises seals, scratches and abrades surfaces, confuses data collection, irritates the eyes and lungs of astronauts, and compromises radiator efficiency. Ground tested cleaning techniques proved ineffective and new ways to both repel and clear lunar dust need to be developed.
Lunar dust adheres to surfaces much more strongly than originally expected. This is due to microscopic hooks present in the particles, and Van-der-Walls forces over a thousand times stronger than for other particles of similar size. The Lunar Dust Adhesion Bell Jar facility (LDAB) studies 1” samples to try and identify important parameters for further study in the probable event of large testing facility construction.
The LDAB stirs dust during pumping down to vacuum to eliminate “burping” of gas before being sieved onto the sample. Sieving controls the particle size and distribution. The vacuum simulation capabilities of the LDAB fall around 10-7 torr, roughly half that of empty space but approximately equivalent to the environment surrounding EVA suits in space.
The LDAB allows for regolith research in several areas including: direct dust adhesion measurements, charge state and bonding character of dust, tribocharging potential, abrasion and wear on seal material studies, and evaluating simulant performance on Earth. It paves the way for research to be done by a future large scale lunar environmental simulator such as the one Dr. Gaier hopes to see installed at Plumb Brook Station in their 25’ sphere.