International Space Station
Credit: Roscosmos/NASA


A catalog of the bacteria and fungi found on surfaces inside the International Space Station (ISS) has been presented in a study published in the open access journal Microbiome.

The study — Characterization of the total and viable bacterial and fungal communities associated with the International Space Station surfaces – reveal a diverse population of bacteria and fungi on ISS environmental surfaces that changed over time but remained similar between locations.

The dominant organisms are associated with the human microbiome and may include opportunistic pathogens is a study finding.

Illustration of the eight locations sampled on the ISS over three flight sampling sessions. a Schematic of the US module of the ISS depicting various nodes and modules. The red arrows point to locations sampled during this study. b Detailed images of the sampled area at each location as outlined by blue lines. Location #1, port panel next to cupola (Node 3); location #2, waste and hygiene compartment (node 3); location #3, advanced resistive exercise device (ARED) foot platform (node 3); location #4, dining table (node 1); location #5, zero G stowage rack (node 1); location #6, permanent multipurpose module (PMM) port 1 (PMM); location #7, panel near portable water dispenser (LAB); and location #8, port crew quarters, bump out exterior aft wall (node 2).
Credit: Aleksandra Checinska Sielaff, et. al

Comprehensive catalog

“This study provides the first comprehensive catalog of both total and intact/viable bacteria and fungi found on surfaces in closed space systems and can be used to help develop safety measures that meet NASA requirements for deep space human habitation,” the study explains. “The results of this study can have significant impact on our understanding of other confined built environments on the Earth such as clean rooms used in the pharmaceutical and medical industries.”

The research work was led by Aleksandra Checinska Sielaff and Camilla Urbaniak of the Biotechnology and Planetary Protection Group at the Jet Propulsion Laboratory in Pasadena, California.

Microbial communities

The study points out that the ISS is a closed system inhabited by microorganisms originating from life support systems, cargo, and crew that are exposed to unique selective pressures such as microgravity.

ISS safety measures regarding the human microbiome are prelude to NASA requirements for deep space human habitation.
Credit: Bob Sauls – XP4D/Explore Mars, Inc. (used with permission)

“To date, mandatory microbial monitoring and observational studies of spacecraft and space stations have been conducted by traditional culture methods, although it is known that many microbes cannot be cultured with standard techniques.”






To fully appreciate the true number and diversity of microbes that survive in the ISS, molecular and culture-based methods were used to assess microbial communities on ISS surfaces. Samples were taken at eight pre-defined locations during three flight missions spanning 14 months and analyzed upon return to Earth.

To read the full report, go to:

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