When astronaut Scott Kelly's space capsule touched down in Kazakhstan, it was a familiar scene to Mark Kelly, who is a retired astronaut and Scott's identical twin.
NASA is conducting a "twin study" on the brothers to explore what spaceflight does to the body. Multiple universities are involved in the research.
"We're going to need to understand this really well before we decide to send people to Mars on an extended mission," Mark Kelly tells NPR's Renee Montagne on Morning Edition. For the study, he acts as a control to compare to his twin, who broke the U.S. record for longest space journey.
Kelly says one part of the study will look into the impact of space on aging. "One of the universities is studying a genetic indicator of how people age, and that's the length of your telomeres. So the length of your telomeres is indicative of your physical age," he says.
Researchers are looking into whether that physical age is linked to the significant amount of radiation that astronauts are exposed to in space, Kelly says. He adds: "I'm not the scientist here, but I would presume the radiation would have a negative effect."
As NASA explains, "The most dangerous aspect of traveling to Mars is space radiation. On the space station, astronauts receive over 10 times the radiation than what's naturally occurring on Earth."
NASA breaks down the components of their study:
- "Research techniques used in personalized medicine (technologies such as genetic sequencing) are employed to discern individual responses to the spaceflight environment
- "Research from the molecular level to whole body function to brain function is being integrated together into one, coordinated study"
While his brother was in orbit, Kelly was providing NASA with his data for the study, including MRIs, ultrasounds, and blood and urine samples.
One effect of the extended time in space has already come and gone, Kelly says. His brother was temporarily 2 inches taller:
"In space without gravity, everybody stretches. But when you get back to Earth, gravity has this effect on you and it pushes you back. So by the time he got back to Houston, they actually measured both of us at about 3 in the morning after he got back and we were exactly the same height again."
Kelly also talked about how his brother is feeling now that he's back on Earth, beyond the shifting height and the unseen effects of radiation:
"You know, he's pretty sore right now and he's tired. People don't sleep particularly well in space. And you know, a lot of hard work and then the fiery return in the Soyuz capsule. So he obviously doesn't feel 100 percent. Except his neurovestibular system is really, really good — I mean, you would expect somebody after that period of time to be dizzy and have balance issues. He doesn't have balance issues. He doesn't have any of that. So he is doing remarkably well."
RENEE MONTAGNE, HOST:
After 340 days in space, astronaut Scott Kelly's tiny Soyuz space capsule landed in Kazikstan. It was a familiar scene to Mark Kelly. He's a retired astronaut and Scott's identical twin brother. NASA is conducting a twin study with the pair. Mark welcomed Scott back to Earth yesterday when his plane landed in Houston and joined us for more. Welcome.
MARK KELLY: Oh, thank you, thanks for having me on.
MONTAGNE: Is it really true, as has been reported, that your brother, Scott, grew two inches in space and is now actually taller than you?
KELLY: Well, yes and no, right? So in space without gravity, everybody stretches. But when you get back to Earth, gravity has this affect on you and it pushes you back. So by the time he got back to Houston, they actually measured both of us at about 3 in the morning after he got back and we were exactly the same height again.
MONTAGNE: Well, other than height, how did Scott seem to you after nearly a year in space? Did you notice any changes besides that?
KELLY: No, but in talking to him, you know, he's pretty sore right now, and, you know, he's tired. You know, people don't sleep particularly well in space. And, you know, a lot of hard work and then the, you know, the fiery return in the Soyuz capsule. You know, he obviously doesn't feel 100 percent, except his neurovestibular system is really, really good. I mean, you would expect somebody after that period of time to be, you know, dizzy and have balance issues. He doesn't have any of that. So he is doing remarkably well. It's the stuff that you can't see that is actually the bigger issue.
MONTAGNE: For instance.
KELLY: Well, the radiation environment that you experience in space is really significant and to be there for a year, you're getting a pretty big dose of radiation. And part of the studies that NASA is doing not only on Scott but on me, it's to explore, you know, what those effects are because we're going to need to understand this really well before we decide to send people to Mars on an extended mission.
MONTAGNE: Right, and what were you doing while Scott was up in space?
KELLY: I did provide all this data to NASA over this period of time. NASA would do MRIs and ultrasounds on me and provide blood samples and urine samples.
MONTAGNE: So those last 340 days you were not just hanging out.
KELLY: Yeah, I was not kept in some lab in the Johnson Space Center. I wouldn't have been too thrilled about that.
MONTAGNE: Let's talk about this twin study briefly. Your down here on Earth serving as a control. Scott Kelly, your brother, is supposed to give us a sense of how the body's affected by prolonged time in space. Give us a few examples of what is being measured.
KELLY: Well, so there are 10 universities, and they're looking at different things. One of the universities is studying a genetic indicator of how people age and that's the length of your telomeres - telomeres. So the length of your telomeres is indicative of your physical age. So they're looking to see if the radiation environment in space is causing astronauts to, you know, I'm not the scientist here but I would presume that the radiation would have a negative effect.
MONTAGNE: You know, let me ask you just something generally. You've both been in space and we heard something about your brother, Scott, after coming down from orbit trying to float his phone to you with rather bad results.
KELLY: I think that was probably something you heard about me throwing my phone to him. And, you know, when you throw things in space, you know, it doesn't take a lot of force. So we were coming back from the space shuttle. He handed me my phone and then I went to throw it back to him and instead of going the required 10 feet it went about two and hit the ground.
MONTAGNE: (Laughter) Thank you very much for joining us and sharing all of this.
KELLY: Oh, you're welcome.
MONTAGNE: Captain Mark Kelly is a retired astronaut. His twin brother, Scott, just returned from a nearly year-long mission aboard the International Space Station. Transcript provided by NPR, Copyright NPR.