A spacewalk planned for Thursday outside the International Space Station was called off late Wednesday because of a “medical concern” with an unidentified crew member, NASA said in a statement.An update shortly before midnight said the agency was exploring “all options, including the possibility of an earlier end to Crew 11’s mission.”Spacewalkers Mike Fincke and Zena Cardman. / Credit: NASA”These are the situations NASA and our partners train for and prepare to execute safely,” the update said. “We will provide further updates within the next 24 hours.”AdvertisementAdvertisementAdvertisementAdvertisementWhile NASA did not identify the astronaut in question or explain the medical issue — standard practice due to privacy concerns — the agency said “the matter involved a single crew member who is stable.”Crew 11 commander Mike Fincke, flight engineer Zena Cardman, Japanese astronaut Kimiya Yui and Russian cosmonaut Oleg Platonov launched to the space station aboard a SpaceX Crew Dragon ferry ship on August. 1.Going into the new year, the crew expected to remain in space until their replacements arrive in mid-February. Crew 11’s return to Earth is expected around Feb. 20. That’s still the official plan.In the meantime, Cardman, 38, and Fincke, 58, a veteran of nine spacewalks on earlier missions, were planning to venture outside the station Thursday to finish building a truss needed to support a set of roll-out solar arrays and to carry out other planned maintenance.AdvertisementAdvertisementAdvertisementAdvertisementA second spacewalk by two yet-to-be-announced astronauts was planned for next week.Japanese astronaut Kimiya Yui and Chris Williams planned to assist Fincke and Cardman in suiting up and preparing the tools and equipment that would be needed outside the space station. / Credit: NASABut NASA called off the the first spacewalk earlier Wednesday, saying “the agency is monitoring a medical concern with a crew member that arose Wednesday afternoon. Due to medical privacy, it is not appropriate for NASA to share more details about the crew member.””The situation is stable. NASA …