Astronauts Butch Wilmore and Suni Williams are conducting a spacewalk outside the International Space Station to remove degraded hardware and swab for microorganisms.

NASA’s two stuck astronauts took their first spacewalk together Thursday, exiting the International Space Station almost eight months after moving in. Commander Suni Williams and Butch Wilmore removed a broken antenna and wiped the station’s exterior for evidence of any microbes that might still be alive after launching from Earth and escaping through vents.

Two NASA astronauts flew to the International Space Station in June on Boeing's Starliner capsule. The test flight was planned for eight days but technical troubles forced the capsule to return empty.

A spokesperson with NASA, which oversees SpaceX’s flights to the ISS, said “NASA and SpaceX are expeditiously working to safely return the agency’s SpaceX Crew-9 astronauts Suni Williams and Butch Wilmore as soon as practical, while also preparing for the launch of Crew-10 to complete a handover between expeditions.”

A SpaceX Dragon spacecraft is already scheduled to return the astronauts under a plan announced by NASA in August.