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Scott Kelly on ISS
NASA astronaut Scott Kelly answers questions from the International Space Station. (Credit: NASA)

NASA astronaut Scott Kelly is getting ready to come home after spending a longer stretch in orbit than any other American in history, but he says he could stay in space for double that time.

“I could go another 100 days. I could go another year if I had to. It would just depend on what I was doing and if it made sense, although I do look forward to getting home here next week,” he told journalists today during a space-to-ground news conference.

The next few days will cap off a 340-day tour of duty on the International Space Station, which is aimed at studying how long-duration spaceflight could affect astronauts during even longer trips to Mars and back. Kelly and his fellow year-in-spacer, Russian cosmonaut Mikhail Kornienko, are due to come back to Earth in a Soyuz capsule along with Russian crewmate Sergey Volkov on March 1.

Kelly now holds the U.S. record for longest continuous time in space, but not the world record: That belongs to Russia’s Valery Polyakov, who stayed on Russia’s Mir space station for just over 437 days.

The International Space Station is a lot more comfortable than Mir was, Kelly said, but some things will have to change when planners design the spacecraft where Mars-bound astronauts could spend 500 days or more.

“Probably almost half the time I’ve been here, between sleeping and working on the computer, I’ve spent basically in a box the size of a phone booth,” he said. “Making that private area as perfect as possible, I think, would go a long way toward reducing fatigue, reducing stress and helping for a successful mission.”

Also, it’s a little tough to do without running water for nearly a year. “It’s kind of like I’ve been in the woods camping for a year,” he said.

Kelly said he’s experiencing some vision impairment – which turns out to be a common complaint for long-duration spacefliers. But for the most part, he said, “I feel pretty good.”

“The hardest part is being isolated in a physical sense from people on the ground that are important to you,” Kelly said.

One of those people is his twin brother, Mark Kelly, who also served as an astronaut until his retirement from NASA in 2011. The two brothers, who turned 52 this week, are participating in a study that focuses on how spaceflight affects biological functions, all the way down to the genetic level.

In his own video recap, Mark Kelly said he’s been giving samples of his blood, saliva, urine “and other things” for comparison with Scott’s samples. He’s also been going through rounds of MRI scans and ultrasound tests. Those readings will be compared with Scott’s test results after the return from space.

Mark said he and Scott have kept in closer touch during the “year in space” experiment than they do when they’re both on Earth, perhaps in part because the contacts help keep Scott’s spirits up. But now that Scott is winding up his tour of duty, Mark is noticing a change in routine.

“I can tell he’s getting ready to come home, because I get less phone calls,” he said.

As anxious as he is to come home from his current trip, Scott Kelly said he was more anxious at the end of his previous 159-day stay on the space station. “I think that probably had a lot to do with the fact that my sister-in-law, Congresswoman Gabrielle Giffords, was shot two months prior,” he said.

That was back in January 2011, when Giffords – Mark Kelly’s wife – suffered a severe head injury as the result of a Tucson assassination attempt. Since then, Giffords retired from Congress and made an amazing recovery. Now Mark Kelly and Gabrielle Giffords are getting ready for the homecoming party in Houston, along with Scott’s girlfriend, his two daughters and other family members and friends.

Scott Kelly said the first thing he planned to do after finishing up his post-landing medical tests at NASA’s Johnson Space Center was “jump in the pool.” Meanwhile, Mark Kelly is planning Scott’s next big journey: a fishing trip to Alaska.

NASA TV will provide live coverage of the space station’s change-of-command ceremony on Feb. 29 and Kelly’s return to Earth on March 1. Check NASA’s TV listings for the schedule. Also, PBS stations will air the first part of a documentary series titled “A Year in Space” on March 2. Check local listings.

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