NASA Study Shows Space Makes Identical Twins Less Identical

If an identical twin brother spends a year in space, will he return to earth different than his sibling?  The answer is: yes.  That’s the result of NASA’s twins study, out this month in Science magazine.

In 2015, NASA sent astronaut Scott Kelly to the International Space Station.  His brother, Mark, stayed home.


Researchers found that being in space altered biomarkers in Scott’s body called telomeres.  They typically shorten over time, which puts a person at higher risk for age-related health problems, but Scott’s telomeres lengthened

Space travel also seems to have changed how some genes work in Scott’s body. 

GPB’S Bill Nigut spoke with Scott after his return to earth, and On Second Thought revisited that conversation since the study results are out this month.  

Interview Highlights

On identical twin brothers diagnosed with cancer, in opposite prostates.

I flew in space twice, then I had prostate cancer and had surgery and flew twice after that for 500 days in space. And, you know, a long duration flight, which has actually more stringent medical requirements, but I think it kind of shows people that have cancer that with the right treatment maybe you can continue your life and still have a future.

On Scott’s yearlong mission away from Earth

Interestingly enough, one of the cosmonauts, Gennady Padalka, says when we're in space we miss Earth and when we're on Earth we miss space.

On being launched into space and what it feels like to sit on top of some 280 tons of explosive propellant.

It gets your attention. You know you're sitting on top of a bomb with liquid oxygen. In the case of the Russian Soyuz liquid kerosene is the fuel. Yeah there's very few things in life that are as serious as that.  

On  how 520 days and 200 million miles in space still doesn’t break the record

Yeah, I mean a couple of my colleagues passed me up for total days in space. I still have the longest single flight of an American, but you know records are made to be broken. And hopefully someday people will be spending much more time in space then we have.

On no mission too hard to handle, even if it takes an entire year.

I had just recently gotten back from space when they started talking about a yearlong flight. So, you know, the six months is a long time. I wasn't too interested because you know it's hard, but then as I got further away from it I thought, I want to fly in space again and I want it to be different and if I flew another six-month flight it might not be that different. A year would make it twice as challenging or more and I was right. So, eventually I came around to the idea. 

On struggling with a divorce and caring for two children

Yeah, that's the hardest thing about being in space for a long period of time - it's not your personal safety, but you always worry about the safety of your family and your loved ones on earth because if something happens to them you're not coming home. I experienced that firsthand on my flight before that when my sister in law Congresswoman, Gabrielle Giffords, was shot in Tucson Arizona.

On receiving tragic news

So, I was working on the toilet it was Saturday Jan. 8, 2011, and I got a call from the control center and they called me to the radio basically and said they were going to privatize a space to ground channel [because] the chief of the astronaut office needed to talk to me. She came on about five minutes later and said, you know, I don't know how to tell you this so I'm just going to tell you: Your sister-in-law Gabby was shot. 

I asked them to tell me everything. They said that the Associated Press was reporting that Gabby had died, and she had not.

Tillman, my good friend, he said to me, I don't know how I know this, but I just know you know Gabby’s not dead. It doesn't make sense. She's still in the operating room so she hasn't died, and he was right. 

On Gabby and brother Mark advocating for better gun safety laws

I mean that's their issue, that's you know, their cause. I have my own opinions. One of which is clearly we need to do something, right? Because what we're doing doesn't really work. So, something should be done. Otherwise people are going to still be killed in this country with guns on a regular basis so I'm just shocked that our government basically has chosen to just absolutely ignore this issue and do nothing about it.

She's got some, you know, significant disability as a result of the shooting. And it's something that, you know, she and her family is going to have to live with for the rest of her life. In some ways, you know, because she was a public person she has meaningful work to do to help in this area. So, that's a positive thing that she has that to occupy her time and to do something very important.

On tragedy continuing back on earth, Scott’s reaction to the 2003 disintegration of Columbia shuttle and loss of friend Laurel Clark.

Three of my classmates were on Columbia - four other of my colleagues. It was a national tragedy, you know, really unfortunate.

Laurel used to pick Samantha up [his daughter] and take her and Ian [her son] to the zoo and on the weekends and my family and her family would spend time together.

On joining the crew looking for pieces of the Columbia wreckage

Yeah, it was quite an odd thing that that space shuttle broke apart over Texas. The people that worked closest with the crew members, fellow astronauts, engineers, instructors, were only a two-hour drive from the crash site. 

On gorillas in space and an unusual takeoff gift

He says, 'I'm sending you a gorilla suit' and it got a lot of attention, some negative from some folks that like to criticize NASA. You know, why would NASA spend all this money to fly a gorilla suit? Well, you know, NASA spends money to fly foam and packing material and sometimes lead ballast so, it really doesn't cost anything to fly a gorilla suit. I thought about how sometimes I'll go to schools and try to talk to kids and there's always this kid like me that was in the back of the room not paying attention. Well, a gorilla in space, you cannot not pay attention to that.

On flying back to Earth in a Russian capsule

It's crazy actually thinking about it. You know, you undock from the space station and fire some engines to slow down by just a few hundred miles an hour and then right after that the three sections are exploded apart. Some of the pieces are actually hitting the window right by the side of your head. You can see stuff, debris flying outside as you hit the atmosphere. Pretty soon you're in this 3000-degree fireball. It gets hot inside, you have pieces of the heat shield flying by, looks like just white, hot burning material. Eventually the window just burns to a crisp and you can't see outside anymore. It's kind of like going over Niagara Falls in a barrel, but while you're on fire. But as soon as you realize you're not going to die - The most fun you've ever had in your life. You know, if I hated being in space for a year I’d do it all over again just for that last 20 minutes.

On being retired and missing space

[I miss space] every day.

It's type two kind of fun. Type one fun is the roller coaster - it's fun while you're doing it. 

Type two fun [are] the things that are fun when you're done and yeah, it's definitely that.