‘Twins Study’ Reveals Resilience of Human Body in Space

NASA researchers say a study of how retired twin astronauts Scott and Mark Kelly were affected by space will help future missions understand how to maintain crew health and critical mission functions during future, deep-space exploration. (Derek Storm / NASA)

(CN) – A landmark study of an astronaut who spent nearly a year in space – and his Earth-bound twin brother – offers clues to the physical and genetic toll that long-term space travel can have on the body, NASA said Thursday amid efforts to boost deeper exploration of the Final Frontier.

NASA officials announced in March that the agency would embark on a new era of deep space exploration marked by missions to place humans on the moon again and eventually a round-trip, human mission to Mars.

The agency rigorously prepares astronauts for their missions, planning everything from their lifestyle, diets and work routines while in space, and also rehabilitates their bodies through reconditioning programs.

But understanding how to maintain peak health of a human crew during extended space travel – and preserving their ability to perform critical tasks – is crucial for planning future interplanetary missions, agency officials said.

Ten teams of NASA researchers took a step toward that goal, launching a study that reveals both surprising and reassuring data about how one human body adapted to and recovered from the extreme conditions in space.

Researchers closely studied astronaut Scott Kelly’s body as he spent 340 days in low-Earth orbit aboard the International Space Station, monitoring how his body adjusted to known hazards of space exploration including weightlessness and space radiation.

Kelly’s identical twin, retired astronaut Mark Kelly – who in February announced his run for the U.S. Senate seat once held by Sen. John McCain of Arizona – remained on Earth and provided researchers a baseline for observation.

The Twins Study, published Thursday in the journal Science, found changes in Scott’s cognitive function and shifts in his gene expressions but largely determined that his immune system responded well while aboard the space station.

A flu vaccine administered in space, for example, worked exactly on Scott’s body as it would have if administered on Earth, researchers said in a statement Thursday.

On gene expressions – signifiers of how bodies are responding to their environments – researchers said a small percentage of genes that are part of Scott’s immune system, like genes tied to regulation of DNA repair, did not return to baseline upon his return to Earth.

Jennifer Fogarty, lead scientist of the Human Research Program at NASA’s Johnson Space Center in Houston, said in a statement that the study provided clues on key genes to monitor during future extended missions.

“A number of physiological and cellular changes take place during spaceflight,” Fogarty said. “We have only scratched the surface of knowledge about the body in space. The data captured will be explored for years to come.”

The study, which took place from 2015-2016, also found that telomeres in Scott’s white blood cells – markers of aging at the end of chromosomes – were surprisingly longer in space but became shorter after his return to Earth.

In contrast, his brother’s telomeres remained stable throughout the entire period he was observed on Earth, researchers said, adding that they would study telomeres in future one-year missions to determine if the results are repeatable.

The opportunity to study how the human body responds to space travel using two people with a high degree of genetic similarity provided scientists with a rare and ideal control group, and a reduced number of variables, both important to scientific studies.

During the study, Scott became the first American astronaut to spend nearly a year in space.

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