NASA has postponed a planned spacewalk and is considering an early return for a four-person crew from the International Space Station due to an unspecified medical issue with one astronaut. The agency stated the crew member is stable and that crew safety is its highest priority. Details about the astronaut and the medical concern have not been disclosed, citing privacy. The decision impacts routine maintenance and scientific objectives, with a second spacewalk also under review. This marks a rare instance of a mission potentially being shortened due to a medical event in orbit.