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FORT COLLINS, Colo. — A groundbreaking NASA study of identical twins is giving scientists a better idea of how spaceflight impacts the human body. One of 10 principle investigators of the study is a professor at Colorado State University.

CSU’s Susan Bailey, PhD., analyzed the ends of chromosomes to compare the health of identical twins — and former astronauts — Mark and Scott Kelly.

Her findings, along with her colleagues’, were published Thursday in the journal Science.

In 2012, NASA picked Scott Kelly for a one-year mission in space while his identical twin Mark Kelly stayed home on earth.

“They’re remarkable individuals,” Bailey said.

As part of the study, more than 300 urine, fecal and blood samples were collected from the twins.

“To actually be working with the astronauts, and even today, being able to talk to them on the phone and get their perspective — that was just amazing,” Bailey said.

Bailey participated in a teleconference with the Kelly brothers, reporters and fellow researchers on Thursday.

Bailey says the ends of Scott’s chromosomes — also known as telomeres — were significantly longer at every stage and in every sample tested during his mission in space. That’s a good sign for Scott’s health, because telomeres help protect chromosomes. They get shorter as one ages.

But Bailey’s work also discovered that after Soctt returned to earth, his telomeres shortened quickly and then stabilized.

“Not that it’s so dramatic that he’s come back much, much older or anything — but it could add up to being accelerated aging,” Bailey said.

Bailey says Scott had many more short telomeres after spaceflight than he did before leaving earth.

“He would perhaps be at increased risk for some of the things that we know are associated with short telomeres like cardiovascular disease and some cancers,” she said. “It just tells us that we need to be monitoring the astronauts when they come back.”

Her findings show that space travel, in the end, could very well have a faster aging impact on the human body.

What is unknown is exactly why space travel impacts age and health. Researchers say more studies are needed. Going forward, Bailey says there will be more studies on this focus.