WASHINGTON, March 5 (UPI) -- Scott Kelly is feeling the effects of his year-long mission in space a few days after returning to earth, he told the media Friday.
Kelly spoke about his return to earth at a NASA news conference and said his most recent stint on the International Space Station was the most taxing on his body, adding that it felt much longer than 340 days.
"I think the only big surprise was how long a year is," Kelly said according to the New York Times. "It seemed like I lived there forever. It seemed longer than I thought it would be."
His body exhibited various symptoms as it readjusted to the earth's gravity. He experienced fatigue and said soreness in his atrophied bones and muscles was, "a lot higher than last time." He also described a burning feeling on his skin, after experiencing far less physical contact while in orbit.
Some changes to his body that occurred in space were also quickly reversed, as kelly grew about two inches in space but returned to his previous height as gravity compressed his spine.
"He's been squished back to normal height," said Kelly's twin brother and retired astronaut Mark.
The brothers will undergo a series of medical tests as part of NASA's "Twins Study" to see how their bodies measure up after spending a year in the varied environments of Earth and space.
"By looking at Mark's results collected over the course of the year, we can see what the normal variations might be," NASA researcher Dr. John Charles said. He added that comparing that standard to Scott's changes "will tell us what areas to investigate in the future."
NASA hopes to apply the data collected to study the viability of future missions to distant locations such as Mars.