Recently returned from a groundbreaking 340-day space mission, astronaut Scott Kelly announced Friday he will retire from NASA on April 1, but still continue to participate in research related to his space travel.

"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, 52, said in a statement from NASA.

"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. 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," he said.

Kelly was selected by NASA in 1996, flew in space four times, and currently holds the American record for most time spent in space — 520 days.

His record-breaking extended space flight, from which he returned earlier this month, was aimed at understanding how long periods of time in space affect the body. His twin brother, former astronaut Mark Kelly, served as the control variable for studying changes in Scott's body.

Also providing data for scientists was cosmonaut Mikhail Kornienko, who launched and returned with Kelly.

"Scott's contributions to NASA are too many to name," said Brian Kelly, director of Flight Operations at NASA's Johnson Space Center in the statement. "In his year aboard the space station, he took part in experiments that will have far-reaching effects, helping us pave the way to putting humans on Mars and benefiting life on Earth."

NASA administrator Charles Bolden offered his thanks to Kelly:

"All of us in the NASA family — and indeed in the broader scientific community — are grateful that he was willing to sacrifice time with his loved ones, meals that don't come in a bag, a cold beer, hot showers, cool autumn breezes, the sounds of birds chirping, the ability to lay his head on an actual pillow and so much more of the pleasures of life during his year of research and experimentation the International Space Station."

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