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NASA twins study may shed light on mysteries of microgravity

Irene Klotz, Spaceflight Correspondent
Mar 27, 2015, 10:34 UTC

Sen—When NASA assigned astronaut Scott Kelly for the first U.S. year-long mission in space the fact that he had an identical twin—who was a former astronaut to boot—was completely beside the point.

There were no special medical studies being planned, and after Kelly asked if any experiments would make use of his twin, scientists quickly panned the idea since any findings would need dozens or hundreds of twin pairs to be statistically significant.

But then the idea began to take root. NASA scientists wondered if studying two such genetically similar people, one in space, the other on Earth, might provide clues about how the human body changes in microgravity.

“The classic question is ‘How much of our health and our behavior is determined by our genes, and how much by our environment?’—the nature versus nurture discussion,” Craig Kundrot, deputy chief scientist of NASA’s Human Research Program, said in a NASA interview.

“In this case we’ve got two genetically identical individuals and we can monitor what kind of changes occur in Mark in an ordinary lifestyle and compare that to the changes that we see in Scott in flight. When we see significant changes in Scott that we don’t see in Mark then we have a good clue that we’re on to something to follow up on,” Kundrot said.

“It could be the weightlessness. It could be the radiation. It could be the isolated, confined nature (of spaceflight.) There are several aspects of spaceflight which pose a challenge,” he added.

NASA put out a call for proposals and selected 10 investigations that make use of the twins. The experiments run the gamut of human life sciences, including psychological evaluations, physiological changes and genetics.

The genetic investigations are new to NASA, which will be taking advantage of commercially available gene sequencing services to assess if the 51-year-old brothers show unexpected divergence.

Researchers already have collected saliva, cheek swabs, urine, feces and blood samples from the brothers and will do so several more times throughout Scott Kelly’s year-long spaceflight and for about six months after his return in March 2016.

“We’re in a good position to see some subtle changes that we wouldn’t be able to see in two individuals who weren’t identical twins. Those will be clues. It’s very unlikely we’ll have a definitively result from this study,” Kundrot said.

Scott Kelly is due to blast off aboard a Russian Soyuz rocket on Friday along with cosmonauts Mikhail Kornienko and Gennady Padalka. Kornienko will be staying aboard the International Space Station with Kelly for a year, twice as long as crewmembers typically serve.

The year-long flights are the first aboard the International Space Station, but the former Soviet Union flew four cosmonauts on the Mir space station for missions lasting between 366 and 438 days. The last flight was in 1999 and the data is largely moot due to advances in medical technology since then.

The point of the year-long flights is to collect information on how the human body changes during extended stays in space, such as what will be needed for expeditions to Mars. 

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