The Micro-Gravity Sediment Trap: A Passive Filtration Device for Spacecraft Pumped Fluid Loops

Pumped fluid loops (PFLs) are critical for thermal and environmental control systems in satellites and in manned spacecraft like the International Space Station (ISS). However, a significant percentage of Western spacecraft PFLs experience failures (~17\%), and about half of those are due to debris in the system, prompting an increase in filtration research in microgravity environments. Current state-of-the-art (SOTA) solutions rely on active filtration, which requires the use sieve type filters (e.g. stainless steel mesh) or porous media, such as activated carbon or sintered ceramic; all of which actively block fluid flow to remove debris. Over time these filters become clogged, incurring a significant increase in pressure drop across the device, and a corresponding higher risk of system failure. The Micro-Gravity Sediment Trap (MGST) offers an innovative, high-efficiency passive filtration alternative, designed to augment or potentially replace active filter components in spacecraft PFLs. MGST has no orifices, bypass lines, or porous media, resulting in a very low pressure drop compared to active filters. Ground tests conducted with the current MGST design indicated exceptionally high particle trapping efficiencies (>94%) with particle sizes ranging from ~1 µm to 150+ µm. A flight test unit was subsequently designed and constructed to test the viability of MGST in a microgravity environment, specifically on the ISS. This paper focuses on flight unit design, post-flight data analysis techniques, and results obtained from the on-orbit test.