NASA Astronaut Scott Kelly reportedly grew taller once he returned to earth after spending a year in space.

When Scott Kelly landed on earth after a year-long space flight mission with the International Space Station (ISS), he was 2 inches (5 cm) taller. According to The Verge, such growth happened because the lack of gravity in space made his spine stretch.

However, his new height is only temporary because the gravity-filled earth will eventually shrink him back to his original height.

"Astronauts get taller in space as the spine elongates," Jeff Williams of NASA said. "But they return to preflight height after a short time back on Earth."

Kelly's twin brother, Mark, who is also an ex-astronaut, is also part of NASA's "Twin Study." In addition to NASA monitoring Scott's body after 340 days in space, they will also be studying Mark by comparing the two after spending a year apart in space and on earth.

"Our studies will provide important data on how the space environment impacts the human body at the molecular level so that NASA can identify risk factors and countermeasures for possible health issues induced by prolonged space travel, such as a mission to Mars," said Brinda Rana, lead investigator from the University of California San Diego School of Medicine team, who will study the twins, in a press release.

As noted by NOLA.com, there will be 10 official experiments that will be conducted on the twins. Six will look at how the body ages in space as well as how the immune system and genes are affected by radiation exposure and low gravity in space. Another two studies will center around the changes in the body, specifically how bodily fluids can affect eyesight. This has become an increasing concern among astronauts.

One study will focus on Scott Kelly's perception, alertness, reasoning and more in a psychological test to determine how his mental faculties have changed after his stay in space. The microbes inside the twin's guts will also be compared and analyzed to determine whether a year in space affects the microbe ecosystem in the stomach.


Kelly landed on Wednesday aboard the Soyuz TMA-18M spacecraft in the town of Dzhezkazgan, Kazakhstan. He was with other Russian astronauts, Mikhail Kornienko and Sergey Volkov of Roscosmos. He returned to his hometown in Houston, Texas on Thursday and was greeted by his family, NASA colleagues and Vice President Joe Biden's wife, Jill, Inside Edition reports.

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