NASA astronaut crew member Scott Kelly will retire from the agency, effective April 1. Kelly joined the astronaut corps in 1996 and currently holds the American record for most time spent in space, plus holding the record for longest American spaceflight at 1 year. Kelly flew in space four times, first aboard the shuttle Discovery,STS-103 servicing mission in 1999, with a trip to NASA’s Hubble Space Telescope. On his second mission, STS-118, he crossed the threshold of the International Space Station for the first time as commander of space shuttle Endeavour. He returned to the station for a six-month stay in 2010, commanding Expedition 26.
Full NASA article HERE