Plasma-Based Techniques for Spacecraft Contamination Control

In this NASA Phase I SBIR, CU Aerospace and the University of Illinois Microbiology Department will partner to develop compact sterilizers based on plasma-generated Reactive Oxygen Species (ROS) technology.nbsp; Specifically, the team will apply radio frequency electric discharges operating at moderate pressure (5-50 Torr) in O2:He mixtures to generate significant quantities of reactive species, especially singlet delta oxygen, referred to as O2(a), a known sterilant of various microorganisms.nbsp; The afterglow exhaust from the plasma generator will be flowed over samples of spores (e.g. G. stearothermophilus), and the inactivation rate of the spores at various plasma reactor settings will be determined.nbsp; Various reactive oxygen species (electronically-excited singlet O2, O atoms, ozone) produced in the plasma reactor will be characterized while flow temperatures will be monitored spectroscopically, and these results will be used to derive exposure conditions suitable for sterilization of various spacecraft materials. A methodology for quantifying bacteria inactivation on various materials will be devised. The team will develop a preliminary design for a prototype demonstration unit which simulates an in-situ sterilizer configuration for validating application on exploration missions.