The US astronaut, Scott Kelly, spent 11 months aboard the ISS, cutting 5 minutes and 13 milliseconds off his Earth age in the process.

Scott Kelly is a 53-year-old American astronaut. He retired last year after spending 11 continuous months on the International Space Station. NASA’s veteran orbited the Earth 5,440 times and made three spacewalks during his time on the ISS.

He was part of a study with his identical twin and fellow astronaut, Mark Kelly. The study examined the genetic effects of spaceflight.

After Scott Kelly landed in Kazakhstan last year following 340 days in space, scientists made a number of tests with him. They did the same tests with his identical twin brother Mark too.

Scientists found that Scott was 2ins taller and 15lb lighter than when he traveled into space.

Researchers have discovered a growth in the 52-year-old’s telomeres – repetitive sequences at each end of a chromosome.

Even though telomeres shrink with age, however, Scott’s grew longer than his brother’s before shrinking back after a few months on Earth.

Scott Kelly has just published a memoir, Endurance: A Year in Space, a Lifetime of Discovery.

The following is a piece of an interview taken from theguardian.

Do you know what the twin study of you and your brother was focused on? And have you been told about any results?

Mostly genetic research but also cognitive studies. The research is still happening. It takes three to five years for the results to be published, so we don’t really know much about the conclusions yet. The one big find so far was that my telomeres, basically these things at the end of our chromosomes that shorten with stress and age, actually ended up longer than Mark’s. It’s the opposite of what the scientists expected, given the challenging environment on the ISS, exposure to radiation, etc. I was already six minutes younger than Mark but, as Einstein predicted, I’ve come back six minutes and 13 milliseconds younger after a year in space.

Thumbnail Image: Identical twins, Scott and Mark Kelly, are the subjects of NASA’s Twins Study. Scott (left) spent a year in space while Mark (right) stayed on Earth as a control subject. Researchers are looking at the effects of space travel on the human body.
Credits: NASA