Officials at NASA and SpaceX have announced that they will return four astronauts from the International Space Station to Earth earlier than planned due to an “unexpected medical issue” with one of the crew members.

The astronauts originally expected to return to Earth around Feb. 20, but NASA announced last Friday that Crew 11 had been told to cut their mission short after a crew member reported a medical issue the day before.

The research has implications for NASA’s goals to build a base on the moon and eventually conduct crewed missions to Mars.

Mark Kelly, a Democratic US senator from Arizona, was censured by Pentagon chief Pete Hegseth. Before his career in office, he was a NASA astronaut.