NASA Reveals Results from ‘Twin in Space’ Study

5 Feb 2017 9:00am, by

It’s a scientist’s dream: a year’s worth of medical tests have been performed on two identical twins — specifically, two 52-year-old Irishmen born in New Jersey — one in space, and one on earth.

Last week, NASA released the first results from its experiments. And on Twitter, NASA astronaut Scott Kelly had some fun with the news:

Scott’s brother Mark was also an astronaut, piloting the Space Shuttle in several missions, and also a Navy aviator. Mark flew 39 combat missions during the Gulf War, eventually rising to the rank of captain, and according to his web page at NASA, “has logged more than 5,000 hours in more than 50 different aircraft.” But this mission required him to stay on earth — for a year of what NASA described as being “poked, prodded, and questioned.”

Mark said he misses outer space, according to Inverse, and even as a private citizen, “I would climb into the Space Shuttle in a second.” But instead, it was his brother Scott who was setting a record for the most days ever spent in orbit — 520, and 340 of them consecutive, all on the International Space Station. And thanks to relativity, as formalized by Einstein, Scott is now also 5 milliseconds younger than his sibling, Gizmodo pointed out. But Scott also “came back to this planet two inches taller, with poorer eyesight and a smaller heart,” according to, which saw Scott speak at the International Space Station R&D Conference 2016. “All astronauts go through lingering effects after getting back from space, he reminded the audience — his case was just a more extreme form.”

Having spent the whole year back on earth, Mark joked later that he was “the lowest-paid government employee.”

NASA wanted to compare the twins to understand the effects that a time in space has on the human, specifically the changes in DNA, RNA, and the entire complement of biomolecules in the human body.

Twelve universities pored over the data from the year-long study. And their research techniques included genetic sequencing — the epigeneticist analyzing their biological samples uses the phrase “space genomics” — as NASA explores ”

“The data are so fresh that some of them are still coming off the sequencing machines,” Christopher Mason, a geneticist at Weill Cornell Medicine, told Nature.

And sure enough, when Scott returned to earth, RNA sequencing revealed more than 200,000 RNA molecules were expressed differently, and while unique mutations are perfectly normal, NASA says researchers “will look closer to see if a ‘space gene’ could have been activated while Scott was in space.”

One investigator noticed both men saw an increase in the enzyme that lengthens in their chromosomal telomeres — while Scott’s actually lengthened on the white blood cells they tested. “That is exactly the opposite of what we thought,” Susan Bailey, a radiation biologist at Colorado State University, told Nature, though NASA suggests the results “could be linked to increased exercise and reduced caloric intake during the mission.”

It’s a theme that kept recurring. A lipid panel shows Scott had some inflammation, while Mark had higher levels of 3-indolepropionic (produced by gut bacteria). A study of their gut microbiomes discovered “pronounced” differences at all times, but NASA suggested it was “expected due to their differing diet and environment.” After all, they’d kept Scott exercising more, and they also kept him on a stricter diet.

That day the cargo of fresh fruit arrived

And another study also found that “heavy exercise countermeasures” were increasing Scott’s levels of the hormone IGF-1.

Other results were less dramatic. Both twins received a flu vaccine — both of which performed as expected. And during reentry “there appeared to be a spike in inflammation,” judging by another biochemical marker — C Reactive Protein — but of course, reentry is stressful.

It’s ultimately not clear whether all the data will ever be released — and not just because there’s a lot of data. “The twins negotiated rights to examine the information before publication, in case it contains anything sensitive,” reports PBS Newshour.

But whatever happens, Scott’s one-year stay in space has already been a ground-breaking effort. “NASA knows a lot about what happens to astronauts after six months in orbit,” explained their NASA life sciences lead, Craig Kundrot. “Deep space missions are going to take much longer than that.” But they also wanted to investigate the psychology of it all, with the astronauts filling out questionnaires about their thoughts and emotions. Eventually, their answers will be cross-referenced to their biological samples to see if there are any correlations. Kundrot explained its significance in almost poetic terms.

“When we leave home for 6 months, it’s like a long business trip. Leaving home for a year is a different thing. We are going to miss every birthday, anniversary, graduation and many other milestones. It feels like a big chunk of life — and this could affect the mood or behavior of the space travelers.”

Among the things NASA is investigating is whether space affects a person’s perceptions — not just spatial relations, but also whether they stay alert and continue making good decisions. There are physical stressors — besides radiation from space, there’s also the low-gravity experience (not to mention the constant confinement).

And the results? “The tests found the crew had the greatest difficulties with performing tasks that demanded postural control and stability and muscle dexterity,” reported one NASA page, but “most other measures did not show substantial differences between six-months and one-year flight duration changes.”

They’d even tested fine motor skills on an iPad — pointing, dragging, shape tracing, and pinch-rotating. The study also found that the astronauts on the one-year mission got more sleep — possibly because their schedule was lighter…

But now there’s hard data to plan NASA’s next moves, and Kundrot calls the study “a pathfinder for the agency”.

“With this study, we’re in a position to look at how humans respond to these challenges and put us in a better position to explore far beyond earth and to better understand how we humans function.”

Indeed, NASA says their ultimate goal is to travel to Mars — and beyond. NASA’s space program began refocussing on exploring space back in 2004. So the twin study is part of that larger push to enable longer journeys crossing greater distances by ensuring that the astronauts can stay healthy, according to the web site for NASA’s Human Research Program.

Human Research Program

To that end, they’ve already investigated everything from lunar dust and radiation to the proper diet in space.

But this twin study gave them a radically new perspective.

Scott and Mark Kelly - NASA twin study


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