Recently returned to Earth following nearly a year in space, astronaut Scott Kelly will retire from NASA in April, the space agency announced Friday.
Kelly, 52, returned on March 1 after the extended mission in the International Space Station, floating 250 miles above the planet's surface.
He will continue to participate in tests related to his lengthy stay in space, which could help doctors and scientists prepare astronauts for lengthy stays in space like trips to Mars, NASA said.
"This year-in-space mission was a profound challenge for all involved, and it gave me a unique perspective and a lot of time to reflect on what my next step should be on our continued journey to help further our capabilities in space and on Earth," Kelly said in a statement.
"My career with the Navy and NASA gave me an incredible chance to showcase public service to which I am dedicated, and what we can accomplish on the big challenges of our day," Kelly said.
"I am humbled and excited by new opportunities for me to support and share the amazing work NASA is doing to help us travel farther into the solar system and work with the next generation of science and technology leaders."
Kelly holds the American record for the most time spent in space. He spent 340 days in space during the year-long mission, and altogether has spent 520 days in space, NASA said.
"Records are meant to be broken," Kelly said in the statement. "I am looking forward to when these records in space are surpassed."
Kelly, a fighter pilot with the Navy, was selected by NASA in 1996. He flew in space four times during his career.
Kelly volunteered for the nearly year-long stint in space. He has a twin brother, Mark — who is a former astronaut — giving researchers an near identical genetic duplicate with which to compare effects of long-duration space flight.
Brian Kelly, director of Flight Operations at NASA's Johnson Space Center in Houston, said the experiments Scott conducted during his year in space "will have far-reaching effects, helping us pave the way to putting humans on Mars and benefiting life on Earth."
"Scott's contributions to NASA are too many to name," Kelly said.