Twins in Space

NASA will study twin brothers to learn about how space affects the body

August 12, 2013


After completing a space mission in 2010, astronaut Scott Kelly, left, is reunited with his twin brother, Mark Kelly. 

No one ever pretended outer space is a welcoming place. The human body seems to revolt at the very idea of being there. No sooner do astronauts arrive in space than up to 40% of them begin throwing up. Most of them adjust soon enough, but they may continue to feel dizzy and tired. There’s also back pain, increased blood pressure, and long term health risks—all a result of trying to adjust to zero gravity.

But how much can you blame exclusively on space? NASA now has a way to begin investigating the mystery, in the form of Scott and Mark Kelly, identical twins who just happen to be astronauts.

Oh, Brother!

Mark Kelly has completed four shuttle missions and spent a total of 54 days in space. Scott Kelly has completed two shuttle flights, including a six-month stay aboard the International Space Station (ISS). Mark has since retired from NASA, but Scott is still flying. Scott is set for a full-year aboard the ISS, beginning in March 2015. And that has provided NASA with an unprecedented opportunity to run a nifty experiment.

Twins can be extremely valuable to scientists trying to understand the human body. Because identical twins are a perfect genetic match, most differences in how they age and the illnesses they do or do not develop can be linked to environmental factors or life experiences. NASA will run comparison tests on the two men, both during and after the year-long mission.

NASA will use the results of the study to try to reduce the risks for future astronauts. Long-term plans to explore distant places like Mars and Europa, Jupiter’s moon, will require astronauts to spend long stretches in space, in some cases even years at a time. In preparing to explore deep space, making sure we can survive the trip is a vital first step.

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