Life is all about bubbles. Every cell in your body is a bubble, a membrane holding together a miniature world of organelles, ribosomes, and genetic material. Your body itself is another bubble, a skin wrapped around a wet, salty interior that carries a distant memory of the oceans in which our ancestors lived hundreds of millions of years ago. And our entire planet is a bubble, a thin membrane of oxygen-rich air wrapped around a spinning rock warmed by a nearby Sun.

Being able to perceive our reality this way is one of the gifts of spending time with someone like Peggy Whitson, the poetic yet resolutely humble astronaut who has spent 665 days aboard the International Space Station–the longest duration of any American. Her life story is woven into tonight’s final episode of One Strange Rock, an unusual type of nature show that looks back at Earth from the unique perspective of the space explorers who have left it. But what you can see in 47 minutes on screen only scratches the surface of what Whitson has experienced.

In an earlier post I spoke with Leland Melvin, who also participated in the creation of One Strange Rock. Here I have the pleasure of speaking with Peggy Whitson as she concludes her stint on NASA’s post-flight media circuit and tries to decide what to do with the rest of her life, back in the bubble after so much time looking at all of us from the outside.

One of the most striking things about One Strange Rock is the way it brought together a diverse group of astronauts. What was that experience like for you, as a veteran of the team?

It’s been fun doing interviews with the other astronauts, getting hear: “Oh, that’s how he explains it” or “That’s how she thinks about it.” We work together but we don’t necessarily share all those thoughts or ideas. Then when somebody else asks the question you go, “Huh! That’s a cool way to think about that.” Leland [Melvin] talking about family, Mass [Mike Massimino], with his great sense of humor, sharing his experiences in a very different style.

NASA’s top astronauts flank the creators of One Strange Rock. Peggy Whitson is in the back row, second from right. (Credit: National Geographic)

What’s next for you, now that you’ve wrapped up a historic career as an astronaut?

[awkward pause] I just finished my six-month post-flight tour. We’ll see how that works out. I’m trying to decide now what I want to do when I grow up!

What are the most common misconceptions you run into when you try to explain  your life aboard the International Space Station?

The #1 misconception? The International Space Station, it’s been up there for 18 years, but most people don’t know that we even have a space station, much less one that has had a presence, human presence, a United States presence, on board for those 18 years.

What??

They don’t even know. They don’t know that there are astronauts from the United States up there right now. That’s…a little disheartening to realize. It doesn’t take away from what we’re doing up there—the research is still very interesting, very exciting.

Wow. Among those who do know, what kind of higher-level misconceptions do you encounter?

Most people assume it’s like the movies, where you can turn gravity on and off when you want to. I show them pictures about how I use my feet to navigate, and about losing my callouses after a couple of months off the bottoms of my feet, developing ones on the tops of my toes from sticking them under the handrails. I try to give them a feel that life adapts and changes to these environments.

Do you then see people light up when they realize just how much we’re doing up there in orbit?

The kids have the excitement, absolutely, and that’s where we need to inspire them. They’re the next-generation explorers. I do see it there. With the adults…sometimes it happens.

Hopefully we will get more and more people interested in doing research in space. I think eventually it’s also going to be a great commercial market. People are going to find out that we can do so much more in space, and it provides a different variable without gravity that is going to provide some new insights. I’m very excited about the future of science in space.

Astronauts have been doing scientific research in space for quite a while. What’s changed?

It’s caliber of science we’re doing on the space station now, and the quantity of science we’re doing. In the timeframe that I’ve been on board the station, the science that we’re doing has reached a much higher level. Some of [the research] had to be simple when we were starting, because that’s all we could support. Now we’ve got some really complex scientific investigations going on.

It’s true, I used to see people rolling their eyes about the level of science on the ISS, but I don’t see that much anymore.

Because most people don’t know the space station exists! [laughs]

Being a biochemist I did a lot of tissue-culture research prior to working at NASA and when I first started working there. The investigations we were doing during this last mission aboard the station: We were looking at the bone cells that build in your body, called osteoblasts. We were looking specifically at how they change in your body during spaceflight, because our bones are continuously remodeling and the cells that tear them down—the osteoclasts—are working just fine. The ones that are building up aren’t.

Now we’re looking at the mechanistic level, at what is happening in those bone cells that’s different in zero gravity, and hopefully learning about how to correct it. If we can better correct bone loss in space, where happens 10 times faster than in a geriatric woman here on Earth, that has ground applications, too. We’re doing studies with rodents, looking at different types of drugs to prevent bone loss. And we’re looking at stem cells, seeing if we can proliferate them in large quantities. Most of the types replicated better in zero gravity. I think there’s going to be some big changes in the future [with space science].

Life outside the bubble: The International Space Station contains a tiny bit of Earth transplanted into space. (Credit: NASA/NatGeo)

Do you think the commercial possibilities are strong enough that NASA could privatize part or all of the ISS in the 2020s?

It would be a shame to lose that capability that we have right now. If we can get enough people to invest in the station—pharmaceutical companies or some other people with big money—it is possible that there’d be some commercial partnership thing that would help continue exploration. That could be very exciting.

There are also robotic experiments on the ISS, including the humanoid “robonaut.” Did you work with him at all?

Yeah, I was trying to recover his life, actually. I ended up taking his guts out because he shorted something out and then [the engineers at the Johnson Space Center] wanted all the circuit boards back. So I took his guts out and sent the boards home. [Note: NASA is gearing up to try again with a new version of the Robonaut.]

What are the next big challenges in space exploration? The astronaut interviews on One Strange Rock hint at some future directions.

The show really captured how we’re trying to replicate a whole life support system in low-Earth orbit. Everything is all provided for us here. It’s interesting, the complexity and the interrelatedness of all the pieces that I think is illustrated very nicely in the show. If we go somewhere else, we’re going to have to replicate all of it there.

How much greater are the challenges of a Moon base or a Mars mission compared to what you dealt with on the space station?

There’s a lot more that we have to worry about. Radiation is probably the big one. If we can get [to Mars] faster with nuclear propulsion, that’s going to significantly reduce that radiation risk. Then wherever you get to, you have to have a place where you can bury or partially bury your habitat to give you some radiation protection.

Having a closed-loop life support life system that is very close to a true closed loop, so that we’re not losing any water, is another important thing. On the space station we’re up to about 85 percent right now, which is not bad, but we need to get better if we’re going to spend years getting to Mars, hanging out there, and coming back. We can’t send that much water; even at 85 percent we can’t do it.

We need to get much better at that closed loop system, or go to a place where we can mine water off the surface [like a polar base on the Moon]. Even then, we need to get more efficient so we can carry other things along instead of water. There are going to be lots of things we need to take along!

What about the psychological challenge of going to Mars?

I don’t consider the psychology the biggest part. The success of the crew is going to be based on that, but it’s not going to be a factor that will keep us from going at all. It will be more challenging [than aboard the space station] when you don’t have real-time communication with the ground. We’ve been doing simulations at Johnson Space Center where they do time delays. They end up using a text model system, which turns out to be the most efficient way to handle that time delay, rather than using audio-video all the time.

A journey to Mars is going to feel very different even than going to the Moon [because we won’t be seeing the Earth right outside the window]. The psychology will be: Look at what we’re heading to. Once you lose sight of the Earth, you have Mars to be looking forward to. Leaving Mars might be the hardest part, until you get back to where you can see Earth again.

Peggy Whitson in her (former) native environment aboard the ISS on Expedition 50. (Credit: NASA JSC)

Beyond better life support, what better technologies do we need to expand the range of human exploration?

New engines is the big thing. [High-performance] ion propulsion needs a nuclear power source. I think our society stagnates if we aren’t continuing to explore, and in order to explore we’re going to need to go there faster. There might also be new kinds of radiation protections that we can do at a biochemical, molecular, cellular level to protect the crews. I’m hopeful that we’ll come up with some new ideas that can help us out there.

What about really far-out ideas, like the researchers who are brainstorming interstellar missions?

It’s important to be thinking about those things. A lot of times you think of things as being science fiction, but the creation of the ideas makes you want to solve them. Then in solving them, they give us greater capability. It’s great that people are trying to find the next thing.

If you had the high-performance rocket and life support, where would you most like to go in the solar system?

In the solar system? Mars is pretty interesting, but maybe Europa. I think there’s good potential for life there, and we should go and check it out. It’s exciting that we’re sending a probe there. It’s a first step. We sent probes to the Moon first. We sent probes to Mars first. It’s part of the process.

I’d go to Mars now if we had a way to get there. Hopefully with SLS [NASA’s new rocket] we’ll get there relatively soon. I’m hopeful. But it may take a Lunar Gateway and some intermediate construction at the Gateway to put all the pieces together and get there.