NASA has postponed today's spacewalk outside the International Space Station (ISS) due to an undisclosed "medical concern" with a crew member.

The US space agency has shared few details, other than the fact that the issue arose yesterday and resulted in today's spacewalk being delayed. The single crew member involved is in stable condition, according to a NASA spokesperson.

The spokesperson added: "Safely conducting our missions is our highest priority, and we are actively evaluating all options, including the possibility of an earlier end to Crew-11's mission. These are the situations NASA and our partners train for and prepare to execute safely."

The SpaceX Crew-11 mission is the 11th SpaceX operational mission, and the crew consists of NASA astronauts Mike Fincke and Zena Cardman, JAXA astronaut Kimiya Yui, and Roscosmos cosmonaut Oleg Platonov.

While there is no definitive end date for the Crew-11 mission, the SpaceX Crew-12 mission is due to launch no earlier than February 15, 2026.

Fincke, a Space Shuttle veteran, was initially set to fly on Boeing's CST-100 Starliner Crew Flight Test before being made the pilot of the first operational mission of the Calamity Capsule. He was then moved to the SpaceX Crew-11 mission, along with Yui. Cardman was to have been the commander of the SpaceX Crew-9 mission before being removed (along with fellow astronaut Stephanie Wilson) to make room for the returning Starliner astronauts, Barry Wilmore and Sunita Williams.

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Station commander Fincke and flight engineer Cardman were set to venture outside the orbiting laboratory for a six-and-a-half-hour spacewalk to route cables for a future solar array, install jumper cables, snap photos of hardware, and collect microorganism samples.

Shortly before NASA's announcement, Cardman shared an image of Yui reflected in the visor of a helmet. Yui and NASA astronaut Chris Williams were to run the suit-up operations for today's postponed spacewalk.

While Yui, Williams, Cardman, and Fincke were preparing for the spacewalk, Roscosmos flight engineers Sergey Kud-Sverchkov and Oleg Platonov were investigating the use of AI to transcribe audio files documenting crew activities, and Sergei Mikaev worked on uninstalling a camera that photographed landmarks during the crew's sleep shift.

Williams and Yui later worked on physics and microbiology research.

While the nature of the medical concern is private, NASA is expected to share a new date for the upcoming spacewalk in the near future. ®