The astronaut is stepping away from NASA shortly after returning from a troubled test flight that left him aboard the ISS months longer than expected.

Astronaut Barry "Butch" Wilmore is leaving NASA after a quarter-century of service. Wilmore spent a total of 464 days off Earth during his three spaceflights.

Veteran NASA astronaut Butch Wilmore has retired after 25 years of service, after completing the troubled Boeing Starliner mission. Wilmore, who flew on four different spacecraft and logged 464 days in space,