NASA spacewalkers to swab the ISS for microbial life
Two NASA astronauts are set to venture outside the International Space Station (ISS) in search of signs of life.
Butch Wilmore and Suni Williams should have been back on Earth months ago, but, thanks to issues with Boeing’s CST-100 Starliner capsule, are spending some additional time on the ISS before a planned return to Earth in a SpaceX Crew Dragon.
The plan is for the spacewalkers to collect samples from sites near life support system vents on the exterior of the ISS. Scientists will be able to determine if the ISS releases microorganisms and assess whether any can survive in the harsh environment outside the outpost.
These days, spacecraft and spacesuits are thoroughly sterilized before missions. However, humans carry plenty of microorganisms, and looking at what is collected outside the ISS will inform designs for crewed vehicles and missions to limit the spread of human contamination.
NASA said: “The data could help determine whether changes are needed to crewed spacecraft, including spacesuits, that are used to explore destinations where life may exist now or in the past.”
With Mars now a priority for crewed expeditions, minimizing human contamination on the surface is crucial to avoid misidentifying it as traces of life on the red planet.
Many space agencies take the challenge of planetary protection very seriously. As an example, the European Space Agency (ESA) cites Article IX of the Outer Space Treaty, which requires care to be taken during exploration of the Moon and beyond “so as to avoid their harmful contamination and also adverse changes in the environment of the Earth resulting from the introduction of extra-terrestrial matter and, where necessary, [to] adopt appropriate measures for this purpose.”
This also involves considering missions launched under less stringent standards than those in place today. Older spacecraft, for example, were not always subject to the same sterilization.
Memorably, a camera on NASA’s Surveyor 3 lander, which the Apollo 12 astronauts retrieved, was found to have been contaminated [PDF] prior to launch. Despite vacuum testing, exposure to temperatures below -100° Celsius, and a stint on the lunar surface, scientists found that the microorganisms on the camera had survived. ®
