Investigation of Gamma Irradiation for Planetary Protection Purposes
Abstract
The planetary protection requirements for Mars and icy-moon missions must be met prior to launch. These requirements protect future scientific investigations by preserving the target environment from unwanted Earth biological contamination. The current spacecraft bioburden reduction process relies primarily on Heat Microbial Reduction (HMR) and the occasional use of Vapor Hydrogen Peroxide (VHP) to reduce bioburden on spacecraft. However, many modern spacecraft materials cannot be exposed to such high temperatures and time durations. VHP, although a low-temperature process, is only a surface sterilization technique. Therefore, to provide additional options for spacecraft hardware sterilization, the planetary protection discipline is developing a gamma irradiation microbial reduction technique capable of penetrating bulk materials. Gamma irradiation is advantageous due to its ability to reduce the bioburden of complex geometry instruments, such as deployable antennas, reaction wheel lubricants, and composite structures such as aeroshells, which cannot be sterilized otherwise, or cannot be adequately sterilized by heat. Gamma irradiation is also an ambient temperature technique that can be used on many heat-sensitive subsystems, such as batteries. In this study, organisms that possessed varying resistance capabilities, such as resistance to heat, dry conditions, and radiation, were analyzed. The goal of this study is to provide the planetary protection discipline with a standardized test protocol to begin the validation of gamma irradiation as a standard sterilization technique for flight hardware.
- Publication:
-
42nd COSPAR Scientific Assembly
- Pub Date:
- July 2018
- Bibcode:
- 2018cosp...42E.789D