Mark Kelly on What It’s Like to be One-Half of the NASA Twin Study

May 27, 2019

NASA has wrapped up the first phase of a study on the long-term effects of space travel by using twins as research subjects. Scientists wanted to study people with the same genetics to compare DNA changes in different environments. There was really only one set of twins that would work for this particular study: astronaut brothers Mark and Scott Kelly. Scott spent 342 days in space – setting a new record – and Mark stayed on Earth, acting as a control experiment. On a recent stop in Flagstaff, Mark Kelly spoke with KNAU’s Zac Ziegler about the experience and what NASA has learned so far.

Mark (left) and Scott (right) Kelly
Credit Derek Storm, www.derekstorm.com

Zac Ziegler: The first round of results from NASA’s twin study recently came out. For those who may be haven't heard about it what what was the study about what's your experience been

Mark Kelly: “You know, I was an astronaut for 15 years. So is my twin brother. And because we were twins, on his last space shuttle flight--which lasted for a year, a really long time--they did some science on us. [They] compared to a lot of a genetic and molecular issues, and the goal here is to figure out, ‘How do we send people into space for a really long period of time?’ We want to send people to Mars someday. That’s going to be a two-and-a-half-year mission. We've got a long way to go, and we got to figure out how do you protect people from the radiation in the space environment and the lack of gravity for a long period of time. And they learned a lot, some things were surprises. Some of his DNA expression--which is a little bit different than your DNA. It's what your DNA is actually doing--that stuff changed in my brother, and hasn't changed back yet. We learned a lot, but we have a lot more to learn before we go to Mars for that first trip.”

ZZ: The fact that you two are really the only people on Earth who could have done this, did that affect your decision to take part?

MK: “Well, this whole idea of doing science on Scott and I started after I left NASA. It never came up for my first four space shuttle flights. But after he was chosen to be the guy in space for a year, some of these NASA researchers thought, ‘Well maybe we would be passing up a great opportunity if we didn't bring this up.’ It's the first time we've done genetic kind of research in space, and it’s maybe the beginning of a new part of space science.”

ZZ: We often hear the twins are very inseparable. Had you and Scott spent this much time this far apart in the past?

MK: “Well, you know when I was in the Navy I served over in Japan on an aircraft carrier for two and a half years. I spent time in the Persian Gulf during Operation Desert Storm. We've been separated before. We've each been to space four times. It was a little bit different with him being in space for a year, but there's a phone on the space station and he was able to call frequently. It's a call you usually take, people usually answer if you're calling from the International Space Station, especially because you can't call back.”

ZZ: How closely were you two monitored? Did you have to have similar schedules as far as the amount of physical activity or anything?

MK: “Well, not exactly because he had to do a lot of physical activity on the space station, running on a treadmill and there’s a weight lifting machine, even though nothing has weight, but a resistive machine otherwise the bone loss and the muscle loss would be significant. So I was able to keep kind of a normal schedule, and I certainly would not want to eat space food for a year. But other than that, you know, a lot of samples. NASA would send someone to my house and take 30 tubes of blood every month or so and other things. I would have to do MRIs and bone scans.

ZZ: So now they've got all the scientific measurables there. Is Scott different now that he's back?

MK: “You know at one point, his DNA changed so much that we nearly had to release him back into the wild. But he's recovered, he's okay now. There's some things that haven't changed back in him yet, and that is a serious thing that, when we start sending people out on longer space flights beyond a year, we're starting to realize that we're going to have to have some mitigations against some of the really challenging stuff.”