Astronauts are Going to Check if There are Microbes on the Outside of the Station

On Thursday January 30th, astronauts Suni Williams and Butch Wilmore are doing a 6.5-hour spacewalk outside the International Space Station. Among other goals, they’ll be collecting surface samples from the station to analyze for the presence of microbes.

The ISS “surface swab” is part of the ISS External Microorganisms project. It was developed to understand how microorganisms are transported by crew members to space. It also seeks to understand what happens to those “mini-critters” in the space environment.

The “bugs” that the two astronauts bring back in for analysis will come from areas on the space station near life-support system vents. The idea is to figure out if the station releases those microbes through the vents. Scientists also want to know the size of the release population, and where else they show up on the station.

The Microbes Experiment

Researchers seek to understand how microbes exist and thrive in space and planetary environments. At the moment, the best analog for those is on the ISS, particularly its exterior. So, when microbes find their way out, people want to know how long they survive the radiation. Do quick temperature changes affect them? What else happens to them? Also, scientists want to know if microbes manage to reproduce and how the environment changes that.

Samples from the ISS surface get frozen in special containers and eventually get returned to Earth. Once in the lab, they’re analyzed using culture-independent techniques such as next-generation deoxyribonucleic acid (DNA) sequencing to measure microbial community. Functional pathways in these microbial communities are characterized by targeting multi-gene analysis. This approach allows for a comprehensive assessment of the microbial diversity and metabolic function without cultivation. The samples collected at different locations or during different EVA opportunities allow investigators to map the microbial diversity of ISS external surfaces.

Why Test for Microbes?

While people have been flying to and from space for decades now, the scientific community still has significant gaps in knowledge about understanding how microbes get released, how they thrive, and what their life cycles are in space. In particular, the ISS sees many visiting vehicles each year, and astronauts move around freely inside. Those activities likely increase the microbe population both inside and out.

Collecting microbes and analyzing them allows scientists to assess the types and numbers of microorganisms living on the outer shell of a spacecraft. The larger goal is to supply more information under the guidelines of NASA’s policy on Planetary Protection Requirements for Human Extraterrestrial missions. There are still many questions to be answered, including: what are the acceptable levels of microbial life? Which ones make it out through the vents? What are acceptable contamination rates? While NASA has designed this mission to answer those and other questions, the Russian space agency Roscosmos is also making similar investigations to sample the Russian side of the station. That resulted in the discovery of non-spore-forming bacteria growing on the outer skin of the station.

The results of microbe analysis from this and other microorganism collections could affect spacecraft design and spacesuit changes. This becomes doubly important when people venture out onto the surface of Mars, for example. While we see no direct evidence of life there now, it could be there and likely existed in the past. Not only do we want to avoid contaminating astronauts with that life, we also want to avoid (as much as possible) bringing Earth life to Mars. This same research has applications in other fields, such as agriculture and pharmaceuticals.

Info on the Space Walk

This isn’t the first time the ISS has been tested for exterior microbial life, and the long-term study is necessary. The planned sampling to be mission undertaken by Williams and Wilmore is officially called Spacewalk 92 and should start at 8 a.m. on January 30th. NASA will provide live coverage of the walk (check here for more information), which will also conduct some other maintenance on the station along with the sampling activities.

For More Information

Astronauts Set to Swab the Exterior of Station for Microbial Life
Space Station Research Explorer

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