NASA twins study confirms long-term space travel changes genes

In this March 4, 2016, file photo, NASA astronaut Scott Kelly, left, and his twin Mark get together before a press conference in Houston. (AP Photo/Pat Sullivan, File)

(WTHR) — The latest findings in NASA's twins study confirm genes may have longer-term changes after spending extended periods of time in space.

A typical space mission lasts six months, but in the age of preparing to go to Mars, NASA is researching the effects of a longer mission. A journey to Mars would reportedly take about three years.

Astronaut Scott Kelly went on a 340-day mission to space in 2015, providing researchers a way to study the changes in human health on a long term mission.

Kelly was the perfect test subject, as he had the perfect control subject: his identical twin, and astronaut brother, Mark. Mark stayed on Earth while Scott took on this stepping stone to a mission to Mars. It was the longest flight ever for an American astronaut.

Researchers discovered some changes to Scott's health were very temporary (back to normal in a matter of hours), while others were much longer-lasting (up to multiple months). Here are some of their findings:

  • The ends of Scott's chromosomes, called telomeres, got longer as opposed to the shortening that is normal with aging. This change was noted in early findings, but the newest data reveals most of his chromosomes were back to normal within two days.
  • While most genes were quickly back to normal, about 7 percent will have longer-term changes to things like DNA repair, the immune system, how bones are formed, and oxygen and carbon dioxide levels in tissues and the bloodstream.
  • Scott experienced decreases in cognitive speed and accuracy after he landed, but not while in space.
  • Spaceflight is linked to nutrient shifts, oxygen deprivation stress, and inflammation.

For more details on the latest findings in the study, visit

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