Flight Environment HEPA Filter Testing for Lunar Dust Removal Capability

Lunar dust is an abrasive compound that can cause critical damage to hardware and crew. The mechanical and chemical makeup various from typical earth dust due to weathering effects. Current space missions require extensive air filtration of lunar dust to ensure mission success; as such filtration testing is paramount in verifying the dust-removal capabilities of the system. Previous testing at NASA GRC consisted of two stages: testing a flat high efficiency particulate air (HEPA) media sheet at various pressure ranges (Stage 1) and testing a pleated HEPA filter at different humidity and dust levels (Stage 2). This testing was done to buy-down risk when testing the flight-qualification HEPA filter for the proposed Stage 3 test. Stage 3 testing consisted of using a flight-ready HEPA filter thereby determining the performance characteristics to verify programmatic requirements. This includes measuring lunar dust loading vs. pressure drop performance and determining a maximum capacity based on the allowable pressure drop, determining the HEPA filter efficiency utilizing two separate methodologies, and assessing if the lunar dust caused the HEPA filter to experience any damage. Additionally, dust removal from the HEPA filter was performed using a vacuum to determine if the filter life can be prolonged. These test results will aid the program in verifying programmatic requirements and ensuring risk buydown before this HEPA filter takes flight.