Outer space changes you, literally. Here's what it does to the human body
EMILY KWONG: [? EMILY KWONG: ?] You're listening to Short Wave from NPR.
REGINA BARBER: Hey, Short Wavers, this is your captain speaking, Regina Barber.
KWONG: And first officer Emily Kwong. We are more than halfway through the Space Camp series. Can you believe that, Gina?
BARBER: I can't, actually. But we've gone past Pluto. We've gone through birthing stars, contemplated the Three-Body Problem and the mysteries of dark matter and dark energy.
KWONG: It's been cool.
BARBER: And today, Em, we're going to turn the focus inward to the existence of our species in space.
KWONG: That's right. Today, we're talking about humans living in space, because let me tell you, when you get the call that you're going to space, it changes your life. After years of flying Navy helicopters, Lieutenant Commander Wendy Lawrence was teaching physics at the US Naval Academy when the phone rang.
[PHONE RINGING]
WENDY LAWRENCE: I'm sitting in my office. The phone rings. I answer it. Lieutenant Commander Wendy Lawrence, may I help you, Sir or Ma'am? Hi, Wendy. How are you doing? This is Don Puddy calling from the Johnson Space Center. Immediately, I know, ooh, this is the good phone call.
KWONG: With this call, Wendy became the first active duty female Naval officer selected for NASA's astronaut program, which meant Wendy couldn't tell anyone for 24 hours.
LAWRENCE: They told me I had to keep it a secret. It was my first official responsibility as a new astronaut candidate, and I'm not going to screw up.
KWONG: Wendy did not screw it up. All told, she has gone to space on four separate missions.
LAWRENCE: I've flown the station arm. I've overseen transfer operations between spacecraft. So every mission is fun because you typically do something different.
KWONG: But as NASA endeavors for longer missions to establish a presence on the moon, maybe put some boots on Mars, they've begun to study the most fragile and variable system of all-- the human body.
BARBER: And sitting pretty 250 miles above the Earth is the International Space Station, which has proven to be the perfect laboratory to analyze the hazards of spaceflight and test out possible solutions.
KATE RUBINS: The majority of what we do is scientific investigations on board the Space Station. So we're setting everything from, how do cells grow and replicate in space, to making drugs with specific crystal forms in microgravity that are actually being used back on Earth for cancer patients.
BARBER: This is microbiologist Kate Rubins, who was hired from an infectious disease lab at MIT to become a NASA astronaut. She has spent 300 days across two missions aboard the Space Station doing experiments related to human health and viral disease. In many ways, her hire represents a generation of astronaut scientists building out our tool kit for space medicine. Today on the show, how our quest to live in space is opening up new doors for science. It's awe-inspiring and filled with calculated risks. We talk about some of the challenges to human spaceflight and what that means for a mission to Mars. I'm Regina Barber.
KWONG: And I'm Emily Kwong.
BARBER: And you're listening to Space Camp, the spectacular summertime space science series from Short Wave at NPR.
KWONG: That was so impressive.
BARBER: Thank you. All right, Emily, you've been looking into how spaceflight affects the human body. And when I think about this topic, I think about poop.
KWONG: Gina, really?
BARBER: Yes, and how astronauts have to poop in microgravity in one of those two toilets aboard the ISS, or in a diaper if they go on a spacewalk.
LAWRENCE: On board the spacecraft, it really is all about creating suction. And generally, the toilets work pretty well. And if they don't, that's really not a good day for you in space.
BARBER: I so love Wendy. I love Wendy almost as much as I love talking about poop.
KWONG: It is one of your top passions. It's true.
BARBER: It is. It is. But OK, back to more serious science. When I think of humans in space, actually, I also think about this twin study.
KWONG: When you told me about this research, I thought it must have to do with twin galaxies or moons or-- but no, it's actually twin astronauts.
BARBER: Mark and Scott.
KWONG: It's Mark and Scott Kelly. They were the twins at the center of a year-long study of astronauts. Here's them talking in a PBS documentary.
SCOTT KELLY: While twins are born with the same genetic material, it changes over time. And maybe it changes more rapidly in space than on Earth. NASA is doing kind of a comparative study between my brother, Mark, and I since we're identical twins.
KWONG: This is from a documentary about the twins. Both Mark and Scott had been to space before. But in 2015, Scott went to the International Space Station for 340 days while Mark stayed on Earth. And because of this study, we know in greater detail what happens to astronauts on long missions.
BARBER: And what are some of those things?
KWONG: It is a long list. A lot of it has to do with the first main hazard to astronauts, which is microgravity. Under those conditions, muscles weaken. In their weight-bearing bones, astronauts lose 1% of bone density a month, which they counter as best as they can with exercise. Scott also got that puffy moon face from fluids filling his upper body and head. Astronaut Kate Rubins remembers the stuffy noses, the colds.
RUBINS: If you want to feel this at home, you can go lay down on your bed or your couch and hang your head off the end of the bed and kind of feel all that blood rush to your brain.
BARBER: Done it.
RUBINS: That's what it feels like in space.
KWONG: Except in space, Gina, it stays that way for months. This long-term shift in fluids, it led to Scott's eyes changing shape, which affected his vision. His heart got rounder, too, as his blood vessels swelled and his carotid arteries started to thicken. A 2019 paper found that some astronauts on the Space Station experienced stagnant or reversed blood flow in their jugular vein, some of which led to clotting.
BARBER: Wow. And these clots are not good-- not in space and not on Earth.
KWONG: And that's why the twins study is so valuable. I'm glad you told me about it, because it really pointed a compass arrow down all of these research pathways, like, one arrow screaming, look at the heart in space. So years later, Kate, our astronaut, took part in the Cardinal Heart Study. She helped engineer cardiovascular tissue on the Space Station and determined how that tissue was impacted by microgravity.
BARBER: Wow. OK. So microgravity is one hazard to spaceflight. What's another?
KWONG: Simply being aboard the International Space Station, which is considered a hostile closed environment. And that is a problem the longer you're up there because we now know space travel weakens the immune system. So Kate told me that, historically, it's happened that a small number of astronauts have developed these painful blisters aboard the Space Station. And NASA later learned that was symptomatic of shingles, a reactivation of a previously had chickenpox virus.
RUBINS: So things like come back for healthy adults on Space Station-- herpes virus. So we definitely don't want a crew on the way to Mars to have an issue with endogenous viruses.
BARBER: So what's an endogenous virus.
KWONG: It's basically a sequence from a virus that hangs out in your cells in stealth mode and can reactivate. That's why paying attention to immune system responses on the Space Station is so important. Astronauts are also always on the lookout for microbes. And historically, if there were some weird growths on the wall or in their water, astronauts had to go through this really complicated, months-long process to figure out what it was.
RUBINS: We would take a little swab sample, we would streak it on a plate. We had to physically send it back to Earth. It would land in Kazakhstan. We would send some NASA people over on an airplane to get this plate and to fly it back to the lab at Johnson Space Center in Houston, Texas. And then they could start their microbiology.
KWONG: But because of Kate's work-- she was the first person to sequence DNA in space-- astronauts can now identify what something is in less than a day and track on these microbial communities of concern. It's just one example of how NASA is trying to give astronauts biomedical tools, which will be really important for deepflight mission someday.
BARBER: OK, so there's microgravity, being in this closed, hostile environment. Let's talk about another big one, one that I know maybe a little bit more about, radiation.
KWONG: Yes! I shouldn't sound so excited. Radiation is a silent threat. The exposure to it is real bad.
BARBER: Yes, but I like talking about it because it's something that I, as a physicist, I know what it is. It comes from two places, the radiation we're dealing with in space. One, the sun is sending radiation towards us from solar storms. And two, the high-energy galactic cosmic rays, which are from stuff like exploding stars in space. And NASA is paying attention to this because, of course, exposure to radiation is not good. It can damage your DNA.
KWONG: Right. Because to fix DNA, the human body makes repairs. This radiation and the repair process may increase an astronaut's risk of cancer, heart disease, nerve damage, a whole slew of other medical risks.
BARBER: Yeah, and there has been studies that, are astronauts at higher risk for this stuff? But how high of a risk, has been the studies.
KWONG: Yeah. It's an interesting question, because a lot of our data comes from the Space Station. But the Space Station is in low Earth orbit. It's not getting a ton of radiation. And not every astronaut is like Scott Kelly, who goes up there for over a year. But in Scott's case, radiation did change his genetic material, specifically, his telomeres.
BARBER: Yeah. So telomeres, they're the caps that protect the ends of DNA strands. This is what I've been told.
KWONG: Yeah. After those 340 days in space, Scott Kelly's telomeres, on average, got longer. And this phenomenon of telomere elongation, it was also seen in the all-civilian SpaceX Inspiration4 crew that just went up after only three days in space. It's an interesting discovery. And it's born out of a real change in the research. We are now sending a broader range of people to space. It's not just astronauts with Olympic levels of training like Wendy. It's also regular folks. Christopher Mason, a professor of genomics, physiology, and biophysics at Weill Cornell Medicine sees this is a real research opportunity.
[AUDIO PLAYBACK]
CHRISTOPHER MASON: We have a chance to study how the human body adapts to space for a wider representative group of humanity, so people that might be pre-diabetic, who might have a higher risk of cardiovascular disease, or maybe are a bit older. We've seen William Shatner, for example, doing a suborbital flight.
KWONG: The captain-- the original Captain Kirk.
BARBER: Yeah. He's doing OK?
KWONG: I guess. I mean, this is all, at least to Chris, creating a second space age, but with more widely available data, a more engaged research community, and just the tentpoles of a future where more people are prepared for spaceflight.
MASON: And this is what we'll need to understand to really enable people to live and work in space.
KWONG: And there's actually, Gina, another all-civilian crew going up to space, the Polaris Dawn mission. And they will be continuing some of the biomedical research that was done on the Inspiration4 mission.
BARBER: That's really cool, Em, but I want to go back to where we started, actually, with longer space missions and the idea of people being on the moon or living on Mars. Besides radiation, microgravity, and being in this closed, hostile environment, I think we have time for one more issue. What else are NASA scientists keeping tabs on?
KWONG: This one, to me, is the most fascinating is isolation, confinement. The Space Station is big.
BARBER: Except for you're going to seal and lock the doors. Nobody in, nobody out.
KWONG: So Kate Rubins says that NASA is screening for astronauts differently these days. They're looking for people who can handle what is essentially six months of camping in an environment that wants to kill you.
BARBER: I can't do a day.
KWONG: I bet you could hang. Because when you get the call, you really have to cultivate certain interpersonal qualities-- the ability to lead, but also the ability to follow, to get along with people who are different from you, and to remember what this is all for. Kate told me a story that I've been thinking about. Towards the end of her last mission, she got out of bed one morning and couldn't escape just the monotony of the view.
RUBINS: And I was looking down at all this equipment and supplies and I was thinking, I've seen this every single day of my life for the last, like, 160 days, and it's only a few feet. And I go the same route. I do the same handrails. And so it's like, man, I just don't want to look at this same stuff anymore. So I went over to the windows. I looked down at the Earth. And we were flying over this incredible kind of view of the Great Lakes. And you can see the sunlight reflecting off the water.
KWONG: Oh, that's beautiful.
RUBINS: And that really quickly got me out of my complaining about the tracking over the same area of the Space Station over and over again.
KWONG: Astronauts like Kate and all of the ground support they receive have contributed to discoveries that have transformed life on Earth. I mean, the Apollo program gave us the technology that ultimately went on to power our cell phones. Breast cancer screenings were made better by NASA algorithms. I mean, astronauts may be miles from Earth, but our relationship to them and their relationship to us is constant. Kate was really reminded of this every time she got mail from home.
RUBINS: We have the opportunity to send little care packages to space. Let me tell you, when you're having a bad day and the toilet's broken for the third time--
KWONG: It's the toilet again.
RUBINS: --the experiment's not going right, and you've been in space for four months, and you're a little bit itchy because you got a rash from some of this immune stuff that's going on, a letter from mom goes a long way.
KWONG: Aw. Speaking of letters, Em, we're going to be flying by a black hole next week, and we have a letter for you from our next expert.
PRIYA NATARAJAN: Hey, Short Wavers. It's Priya Natarajan, your commander of Terra Firma speaking. I gather you've left us and are hurtling beyond the solar system, approaching the potential black hole binary near us, OJ 287. Be careful. Don't get too close. Spaghettification near a black hole is no joke.
BARBER: Before we head out, a reminder that we'll be back tomorrow with our regular Short Wave and back Tuesday with another episode of our Summer Space Camp series. This episode was produced by Hannah Chin and fact-checked by Emily Kwong. It was edited by our showrunner Rebecca Ramirez, and it was engineered by Robert Rodriguez. Julia Carney is our Space Camp project manager, Beth Donovan is our senior director, and Collin Campbell is our senior vice president of podcasting strategy. Special thanks to our friends at the US Space and Rocket Center, home of Space Camp. I'm Regina Barber.
KWONG: And I'm Emily Kwong.
BARBER: And you're listening to Short Wave from NPR.
Copyright © 2024 NPR. All rights reserved. Visit our website terms of use and permissions pages at www.npr.org for further information.
NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.