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Molecular microbial diversity of a spacecraft assembly facility
K Venkateswaran1, M Satomi, S Chung
1Planetary Protection Technologies, Jet Propulsion Laboratory, California Institute of Technology, Pasadena 91109, USA. kjvenkat@jpl.nasa.gov
Systematic and Applied Microbiology
|August 24, 2001
Summary
Spacecraft assembly facilities harbor heat-tolerant microbes, primarily Bacillus species, on coated surfaces. Paint formulations significantly influence microbial colonization, impacting spacecraft cleanliness and mission safety.
Area of Science:
- Microbiology
- Space Science
- Astrobiology
Background:
- Microbial contamination poses risks to spacecraft integrity and mission success.
- Understanding microbial ecosystems in cleanroom environments is crucial for planetary protection.
Purpose of the Study:
- To characterize microbial populations in the Jet Propulsion Laboratory's Spacecraft Assembly Facility (JPL-SAF).
- To assess the impact of spacecraft-qualified paints on microbial and dust accumulation.
- To identify heat-tolerant microbial species relevant to spacecraft assembly environments.
Main Methods:
- Exposure of witness plates coated with different paints and stainless steel to JPL-SAF for 7-9 months.
- Microbiological analysis of collected particles for cultivable aerobic heterotrophs and heat-tolerant spore-formers.
- Phylogenetic analysis of isolates using 16S rDNA sequencing, alongside morphological, physiological, and chemotaxonomic characterizations.
Main Results:
- Spacecraft-qualified paints, particularly NS43G, attracted more dust and cultivable microbes than uncoated stainless steel.
- JPL-SAF harbors predominantly Gram-positive, heat-tolerant microbes, including Bacillus species.
- 16S rDNA sequencing identified isolates belonging to Bacillus, Staphylococcus, Planococcus, and Micrococcus genera.
- Direct DNA analysis indicated an equal proportion of Gram-positive and Gram-negative microorganisms, contrasting with cultivation methods.
Conclusions:
- Paint coatings on spacecraft materials can enhance microbial and dust accumulation in assembly facilities.
- Heat-tolerant Bacillus species are prevalent in JPL-SAF and pose potential challenges for spacecraft sterilization.
- Discrepancies between cultivation and direct DNA methods highlight the complexity of microbial community assessment.