NASA astronaut already feels at home in space as 1-year journey begins

NASA astronaut Scott Kelly (left) gives a thumb's up sign while floating next to fellow one-year crewmate Mikhail Kornienko of Russia on the International Space Station after a video chat with NASA chief Charles Bolden and others on March 30, 2 (NASA TV)

NASA Administrator Charles Bolden (right) speaks to one-year astronaut Scott Kelly on the International Space Station via a video link on March 30, 2015. (NASA TV)

NASA's Scott Kelly — one of two people spending a year on the International Space Station — already feels like the orbiting outpost is home.

"It's great to be up here," veteran astronaut Kelly said during a live interview from the space station with NASA administrator Charles Bolden March 30. "It's like coming to my old home."

Kelly has been to the station multiple times, but his current mission is unlike anything attempted on the space laboratory before. Kelly and Russian cosmonaut Mikhail Kornienko (who launched to orbit on March 27) will spend about a year on the space station, the longest amount of time anyone has ever spent living and working on the lab. [See photos from the yearlong mission]

NASA officials hope that the research Kornienko and Kelly conduct on the station during their stay could help send astronauts to Mars by the 2030s. A crew of Mars explorers might need to spend 500 days or more in space, so learning more about what happens to the body in microgravity is important for any space agency hoping to venture farther into the solar system.

At the moment, NASA scientists know a lot about what happens to astronauts after six months in weightlessness — the usual amount of time a crewmember spends on the station. But they have little-to-no information about what happens when a person stays in space for a longer amount of time.

"I really want to thank you for taking on this challenge," Bolden told Kelly during the interview. "It really is important that we get it all right because we do plan to put humans on Mars in the next few decades. The 2030s is the target the president set, and we think we can really make that."

First lady Michelle Obama wished Kelly well via social media when he launched to space Friday: "We have liftoff! @StationCDRKelly just launched for the @Space_Station on his #YearInSpace," she said via Twitter. "Good luck, Captain."

Kelly also responded in kind, taking the chance to post his first photo from space during the yearlong mission.

"@FLOTUS Thank you," Kelly posted on Twitter. "Made it! Moving into crew quarters on @space_station to begin my #yearinspace."

Kelly's identical twin brother and former astronaut Mark Kelly will also help scientists on Earth interested in collecting more data that could send people to Mars one day. Researchers hope to do a variety of tests with the Kelly brothers to see how Scott might change physiologically and even genetically during his long-duration stay in orbit.

"This twin study, it's going to give us, hopefully, information on what we need to one day go to Mars," Mark said during the live interview. "We understand a lot about the engineering of a Mars flight — what it would take to get people there and get them back, but we don't understand a lot about the physiology."