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,

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.

Four astronauts are on their way to the International Space Station after being sidelined by Boeing's Starliner trouble and other issues. SpaceX launched the U.S.