NASA is considering a rare early return of its crew from the International Space Station over an unspecified medical issue involving one of the astronauts, after cancelling a planned spacewalk that had been scheduled for Thursday, the agency said. A NASA spokesperson said that the "medical situation" aboard the International Space Station "involved a single crew member who is stable." The four-person Crew-11 crew includes U.S. astronauts Zena Cardman and Mike Fincke, Japanese astronaut Kimiya Yu