NASA Twin Study Shocker: Space Travel Altered Astronaut Scott Kelly's DNA
In 2015, NASA began a study into how time in space alters the genetics of the human body. The foolproof method for undertaking this process was to use an astronaut, Scott Kelly, whose genes come with a convenient control group, in the form of his identical twin brother Mark.
Over several studies that involved sending Scott to the International Space Station for extended missions, NASA ultimately discovered that much of Scott's genetics had changed dramatically when compared with his brother. Most notably, Scott's telomeres, the tips of his DNA chromosomes, were a lot longer than those found within Mark.
This was an intriguing find at the time; telomeres affect the aging process—over time, telomeres begin to shrink when new DNA is formed, which is a large part of why our bodies get lethargic, wrinkly, and sick as we get older.
This news might be enough to make someone assume that life in space is a foolproof cure for aging, but follow-up research suggests that this isn't the case. According to new research, the majority of Scott's telomeres actually shrank back to match his brother's DNA, and they did so within just two days of Scott returning to Earth.
Meanwhile, a lot of other changes to Scott's DNA have remained constant over time. Scott has now been back on terra firma for a full two years, and in that time, his genetics have still not completely changed back. There's further research to be done, but while Scott was previously identical to Mark, now the pairs' genes display a 7 percent difference.
If you're thinking that a 7 percent change in DNA sounds like it makes a big difference, you're not the only one. Scott has been left somewhat baffled by the news himself:
That certainly is weird. It's also a big concern to scientists that are attempting to calculate the feasibility of long-term travel into outer space, such as a manned mission to Mars.
Scott Kelly spent over 500 days in space in total during these experiments, including one stint of 342 days solid. The journey time to Mars is around 300 days at the shortest when the Red Planet's orbit lines up with our own. Thus, astronauts who take the journey to Mars will be looking at over 600 days in space in order to complete a round trip, and that's to say nothing of eventual frequent flyers who might be making the trip back and forth more often if Elon Musk ever manages to send colonists to go pick up his Tesla.
(That'd be quite the valet service, so he'd better tip well.)
If all astronauts to embark on a mission to Mars are going to see such a large change in their DNA, then there could be all sorts of inherent health risks involved in exposing people to that much zero gravity. We know that astronauts often suffer from headaches and eye strain thanks to their time in space, and even when subjected to a regular intense exercise schedule, their muscles atrophy while they don't suffer from the natural resistance present on our homeworld.
There will no doubt be plenty more studies over the next few years which will look into Scott's ongoing health as he ages, especially when compared to his brother, and we could well learn of the full ramifications of the changes that have occurred within Scott's DNA.
As for whether an extended period of time causes astronauts to grow better mustaches, we'll probably never know.