Airborne Endospore Bioburden as an Indicator of Spacecraft Cleanliness

Bacterial endospores are ubiquitous in terrestrial environments as a result of their ability to persist through environmental extremes of moisture, chemical toxins, pressure, heat and UV radiation. Current studies suggest that Airborne Endospore Bioburden (AEB) may be used as an indicator of spacecraft cleanliness. AEB, as measured in closed environment air sampling under laboratory conditions and in the Environmental Control and Life Support System at Marshall Space Flight Center, has indicated that increased total counts of airborne endospores can be correlated to surface microbial contamination. Advanced detection methods using PDMS sampling techniques, the highly sensitive terbium-dipicolinic acid (Tb³⁺-DPA) endospore assay, and standard microbial monitoring methods can be used to track trends in the settling of airborne spores. AEB measurements have the potential to be used in monitoring surface bioburden to anticipate buildup on critical spacecraft hardware and expedite remediation.