The Impacts of Plasma Treatment on Airborne Microorganisms for Space Environment Applications

Abstract

In space environments, microorganisms such as bacteria and fungi exhibit enhanced growth parameters and resilience to antibiotics, complicating mitigation efforts. This behavior increases risks of structural damage to the spacecraft and health issues such as infections and hypersensitivities among astronauts in closed environments such as the International Space Station (ISS). To address this, a cost-effective, low-waste technology called CAFAAI (Cabin Atmosphere Filtration using Ambient Air Ionization) has been developed for continuous microbial neutralization using the generation of negative plasma discharge. CAFAAI is optimized for low- power operation with no moving parts, making it a low-maintenance option. This study evaluated CAFAAI’s effectiveness in neutralizing three microorganisms commonly found on the ISS – Aspergillus (filamentous fungi), Aureobasidium pullulans (polymorphic fungi), and Bacillus atrophaeus (bacterium). Cultures were nebulized and treated under two voltage potentials and two treatment durations, repeated three times. Microbial survival was assessed by collecting samples post-CAFAAI treatment and monitoring growth on agar plates after incubation. Results demonstrated that higher voltages and longer treatment durations enhanced microbial neutralization for all microorganisms tested. Furthermore, a tradeoff between treatment duration and voltage potential was observed; doubling the contact time decreased the colony forming units on the plates 3x more than doubling the voltage potential. CAFAAI’s ability to continuously reduce microbial loads without producing significant waste or requiring moving parts positions it as a promising addition to spacecraft systems. This technology offers a sustainable solution for maintaining healthier and safer environments for astronauts during long-duration missions.A one-year embargo was granted for this item.Academic Major: Aerospace Engineerin