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 announced his retirement Wednesday after 25 years with NASA and serving as a U.S. Navy test pilot before becoming an astronaut.

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,