Quantification of Spore-forming Bacteria Carried by Dust Particles

In order to establish a biological contamination transport model for predicting the cross contamination risk during spacecraft assembly and upon landing on Mars, it i s important to understand the relationship between sporeforming bacteria and their carrier particles. We have conducted air and surface sampling in indoor, outdoor, and cleanroom environments to determine the ratio of spore forming bacteria to their dust particle carriers of different sizes. The number of spore forming bacteria was determined from various size groups of particles in a given environment. Our data also confirms the existence of multiple spores on a single particle and spore clumps. The results of this study provide realistic inputs in developing the bio-contamination transport model, which in turn will help in better determining forward contamination risks for future missions.