Browsing by Author "Turner, Zach"
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Item Development of a Reflective Silencer for Acoustic Abatement of Airborne Ventilation Fan Noises within the HALO Module.(2024 International Conference on Environmnetal Systems, 2024-07-21) Wadlington, Craig; Wolf-Molnar, Pal; Turner, ZachParagon Space Development Corp. in conjunction with SONUS Engineered Solutions have developed a compact, in-line, noise attenuating reflective silencer to accomplish Noise, Vibration, and Harshness (NVH) treatment of the airborne fan noises within the Inter-Module-Ventilation (IMV) assemblies onboard the HALO Gateway module, targeting to improve the cabin atmosphere habitability for the crew. This silencer technology extends to suit any other airborne noise propagating within cabin ductwork and will be beneficial for all crewed space missions, including commercial Lower Earth Orbit (LEO), lunar & cislunar spacecraft, as well as lunar and planetary surface habitats. This paper presents the design, analysis, test results, and down selection of the silencer under the airflow and noise conditions representative of operations within the HALO Module. Preliminary design yielded multiple concepts which were individually tested, analyzed and ultimately narrowed down to an in-line pocket-style resonator located on the fan outlet side of each IMV assembly. Program requirements specify Sound Insertion Loss (SIL) in the audible frequency range and narrow-band peak Sound Pressure Levels (SPL) as the primary metrics used to quantify NVH properties throughout the assemblies, while also considering mass limitations, mechanical loads, pressure drop, and size limitations of the evaluated silencer solutions. Test results have shown that the current silencer design exceeds all requirements with opportunities for further improvements and forward work identified.Item Flight Environment HEPA Filter Testing for Lunar Dust Removal Capability(2023 International Conference on Environmental Systems, 2023-07-16) Walcker, Andrew; Turner, Zach; Agui, Juan; Green, Robert; Berger, GordonLunar 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.Item Numerical Analysis of Lunar Dust in Support of the Habitat and Logistics Outpost(2023 International Conference on Environmental Systems, 2023-07-16) Brown, Owen G.; Eblin, James C.; Bermudez, Luis M.; Turner, ZachThe NASA Artemis program aims to send humans back to the Moon for the first time since 1972. To achieve this goal, NASA and its commercial and international partners are constructing the Lunar Gateway, a facility that will support scientific research and surface landings on the Moon and help prepare astronauts for future missions to Mars. The Habitat and Logistics Outpost (HALO) module, a critical component of Gateway, is currently under development by NASA and Northrop Grumman. HALO will serve as the first Gateway habitable module where crew members will live and work in the cis-lunar environment. Designing a one-of-a-kind spacecraft orbiting the Moon requires careful consideration of crew safety and comfort. In this paper, we present the results of flow modeling and simulation performed as part of the design of the environmental control and life support system for HALO. Detailed computational fluid dynamic analyses of cabin flow and the effects of a simulated lunar dust seeding event on the cabin environment, examining the spread of dust parcels are presented. Our results cover multiple scenarios, including visiting vehicles, fan speeds, crew operations, and environmental changes. It is shown that the designs provide satisfactory mixing within the module and demonstrated efficient lunar dust removal.