NASA's former chief scientist on why space exploration is vital to humanity

Ellen Stofan is undersecretary for science and research at the Smithsonian and former chief scientist at NASA, where she helped guide the development of a long range plan to get humans to Mars.

In conversation with the World Economic Forum's Nikolai Khlystov, who leads the Forum's work on space, Stofan explained why we should go to Mars, what other parts of the solar system we should be exploring more closely, and how the James Webb Space Telescope is effectively a time machine looking back close to the very start of the universe.

It's a fascinating discussion that digs deep into what life in space would truly look like and how exploration can help us tackle challenges here on earth. Whether you are a space nerd or know next to nothing about space, Ellen talks 'human' about what often seems a subject restricted to the experts. A transcript, edited for clarity, is below.

This transcript has been generated using speech recognition software and may contain errors. Please check its accuracy against the audio.

Nikolai Khlystov: So Ellen, the 1960s and the seventies were a really exciting time for space. Humanity got to space in the first place. We went to the Moon. We sent spacecraft all over the solar system. And since then we've been living in the lower earth orbit continuously for the last 20-plus years on the International Space Station. We were able to do all these missions in the earlier decades without really having the computational power as we know it today. Now, the excitement from that era somewhat diminished over the years, but of course, now things are changing, lots is happening.

Can you tell me a little bit about what are your favourite missions from this year, 2022, and what are you most excited perhaps for the next one or two years?

Ellen Stofan: When you think back to the Apollo era, it was really incredible what they were able to accomplish. In the US, it actually took over 400,000 people working to make Apollo happen. And when you think of the challenge at that time, you know, it was actually really incredible, because we barely had computers, we didn't know what a spacesuit was, we didn't know how to do a spacewalk, we didn't know how to keep astronauts alive in space, full stop. And so where we were technologically and what we had to accomplish in that nine years it took from President Kennedy's challenge to get to the Moon all the way to landing on the Moon in the summer of 1969 was absolutely incredible.

And, of course, to me, again, one of the most exciting parts, since I'm a geologist, was the fact that we learned an incredible amount from Apollo, not just was it a huge technological development, it really moved forward our understanding that, for example, the Moon used to be part of the Earth. And so this incredible knowledge that was gained scientifically as well as this just amazing technological accomplishment. And I think winding through our conversation today, I also want to harp on this inspirational piece that I think is especially valuable today. When there's so much going on that, frankly, it seems really daunting to people in the public, like can humanity really overcome the challenges in front of us? So whether it's climate change, whether it's dealing with global pandemics, you know, Apollo showed that when humanity puts its mind to doing something — again, remember that eight years and what we had to accomplish — I think Apollo is something, you know, people talk about moonshots. The moonshot was a moonshot. You know, let's think back to what that word means and use it really carefully. But let's use that for inspiration. And I can't tell you how many people I've met who run companies around the world — why they did it? They did it because they were inspired by Apollo. And I think that piece, that inspiration piece, is really important.

Nikolai Khlystov: Apollo was absolutely incredible. And of course, there were other missions from other countries that they were doing research there. And the Soviet Union had robotic missions there, of course, as well. But now we're back to the Moon. We're supposed to be going back there with humans in the next three or four years. We've not been there for over 50 years. Are you excited about that?

Ellen Stofan: I'm incredibly excited. I actually have been down to Florida twice last month trying to watch that first launch of the SLS [Space Launch System] for Artemis-1. You know, getting back to the Moon, when you say, well, we did this 50 years ago, what's the big deal? Well, we actually have to go and figure out an awful lot over again. First of all, we had to build a really big rocket and the Space Launch System is a huge rocket. I was actually really impressed. I've seen a lot of rocket launches in my life, but when I went down for the first and second launch attempts for the space launch system, an Artemis-1, I was really blown away by how big that rocket is. And so when that actually launches and right now it's scheduled to go on November 14th, it's going to be incredible because the force, you know, the shockwave, when that hits you, when that thing goes off the ground, is going to be incredibly exciting.

I think to me, this return to the Moon is is so important. We've been in low-Earth orbit for over 20 years, as you said. We've learned incredible things from the International Space Station. We've learned how to live in space. And some people might say, really? Is that is that really a big deal? It is a hugely big deal. If you think of it from how do we feed people over longer periods of time, really mundane things like can we get a toilet that works consistently and doesn't break? You don't want to go to Mars, you know, eight months to Mars, eight months back. You don't want to do that with a broken toilet. Life support systems — how do we keep the air clean? The carbon dioxide levels at an acceptable rate for astronaut health? How do we protect them from solar flares? These are all things we've been learning on the International Space Station, how to keep astronauts healthy in space for long durations, how to live in space. This is a really big deal.

So now we're ready to take that next step. We're ready to go back to the room and say, all right, now we practise getting farther from the Earth. And again, why is that a big deal? Right now, we're incredibly dependent on mission control. You think of this, Houston, we have a problem, right? Ground control is always right there. The time delay is low. The astronauts can get back quickly and easily if there's ever a problem. When you're going to the Moon that's over a three-day trip, it's really far away. It looks close when you see it up in the sky. But boy, the Moon is far. And so doing that can we break this tie from Earth? Get up to the Moon. Practise that kind of remote living from Earth. And then be ready to go on to Mars. So this next step to me is incredibly important. It's incredibly exciting because I'm more of a humans to Mars person. And so we need to do this to get to Mars, and we're right on the brink of actually seeing it happen.

Nikolai Khlystov: Hold that thought, Ellen, for Mars. We'll definitely get to that. And some of those challenges multiply exponentially when we talk about Mars, of course. And by the way, of course, I think I don't know if you mentioned the water filtration systems, right. We've learned a lot from the previous decades, right. And we're using that technology for some filtration on earth as well.

Ellen Stofan: Yeah, that's true. And so when you think about it, you know, water's really heavy. And one of the difficulties with human space exploration, with exploration writ large, it's really hard to get off the Earth. We're a big, we have a lot of gravity. And so the biggest cost of exploration is actually getting things from the ground to space because you have to overcome Earth's gravity to get out there. And this leads to the importance of the rise of the commercial launch industry, which is another whole topic. That's why that's so important. They're trying to bring down the cost of getting off the Earth. Water is really heavy. And so if you're launching water up into space for the astronauts to drink, that's just like a lot of money. So why not reuse water? So on the space station right now, I think they're up in the high 80% if not low 90%, of reusing water. Yes. That means they purify urine and drink it. You know, it's been a taxable problem, but it has some difficulties. When you purify the water, it leaves a brine behind. That's kind of messy. And so trying to get that system to work and have it work well has been a learning process. But we'd love to get up to the mid-90% of water reuse. That means we have to bring less water along. Water's also really important as a possible shield from cosmic radiation, which are high energy cosmic rays that come from deep space, they can do a lot of damage to the human body. It turns out water is a great shield.

Nikolai Khlystov: What do you think we're going to be doing as humans on the Moon? What are some the possibilities? We'll get there in three or four years. Maybe we'll come back. We won't stay right away. But by the early 2030s, late 2030s, are we going to have a permanent presence, maybe a small moon village? I mean, there are some plans for that internationally as well.

Ellen Stofan: I think it's a super interesting concept. And so do you have other governments, do you have the commercial, the private sector wanting to build things on the Moon, being able to, you know, are we going to get- like right now we're looking at private citizens going up to low-Earth orbit. Are we going to get private citizens going to the Moon? Are we going to have this hotel on the Moon? Is there a commercial there? Is there a profit motive? Companies don't do things unless they think I can potentially make a profit on this or I can definitely make a profit on it.

So I think as we go forward, it'll be really interesting to see where the governments want to put their investments and NASA's basic role, is that exploration piece, not the business development piece. Now they want to support the business development and get it moving, but then they want to move on and do the things that are more deep space exploration. So I'll be really curious to see how the next 10 to 15 years develops, how much government infrastructure do we want to invest on the Moon, and how much does the private sector really come in and fill behind NASA like they're doing right now in low-Earth orbit and certainly on the middle earth orbit and higher orbit where you see a lot of private investment. And so this balance between government investment, private sector investment, how that leads to the development of the Moon and then as NASA goes on to Mars, I think it's going to be super interesting.

Nikolai Khlystov: Let's go to Mars, of course, much further away. Can you maybe share a little bit some of the difficulties you alluded to some of them already when we're talking about the Moon, cosmic radiation. But it's just the distance, it's the communication. What are some of the other challenges for us to actually not just go perhaps to the Martian orbit, but actually to land there?

Ellen Stofan: Mars is a whole lot. And so some people look at that and say, oh, it's too hard, we can't do it. And I again go back let's go back to Apollo. You know, we didn't know how to make a spacesuit. We didn't even know how to keep astronauts alive.

First of all, it's a long way there. It's about eight months to a year transit time to get there. You're going to stay for at least a couple of months and then you've got a transit time back of about eight months to a year. So we're talking probably minimum 2 to 3 year mission. That's a long time difference. You're going to be in zero gravity. You're going to be in low Mars gravity. That's hard on the human body. So we're still doing work to make sure we understand how to get humans ready for that. Practising on the Moon will be important for that. Landing on Mars is really complicated, and you see the kind of really complex systems that NASA used to land the Perseverance Rover. The amount of mass we need to land on the surface is about five times. To land these really big rovers on Mars is really complicated, really big amount of mass. Unlike the Moon, Mars has an atmosphere, but it actually helps the spacecraft heat up, but doesn't really slow you down because it's a very, very thin atmosphere. Mars is a much more kind of familiar place to us because it's a planet with an atmosphere. But landing on that surface is just really tough. You need something called supersonic retro propulsion, which is something that Elon Musk and SpaceX have worked on. Again, you're going to heat up that craft coming in and you have to slow it down really rapidly. Huge technological challenge.

Then there's that one-way light time to Mars. It takes about 20 minutes to get a signal to Mars from the Earth. That's just distance and speed of light. And so if you said, Houston, we have a problem, it's going to be 40 minutes to an hour before you hear back. So what does that say? We need computing, we need Artificial Intelligence. We need assistance for the astronauts because frankly, after eight months in space, your reaction times have slowed. And so you're going to need computing support to help you make decisions. Those are just a few of the technological challenges, let alone living on the surface of Mars, growing food, which we're practising, on the surface of Mars. So incredible technologies. They're learning to use Mars, pulling oxygen out of the Mars atmosphere, for potentially rocket fuel or using Mars water to manufacture rocket fuel on the surface. So you can make things on the surface of Mars and bring less with you. We call that in-situ resource utilisation. That's a big technological challenge that we're also going to do some practising on the Moon for.

Nikolai Khlystov: What are some of the reasons beyond the science, in your view, for us to actually go there in person? You've you've mentioned that it feels a little bit more like our own home planet. What does that mean for us as humans if we actually step foot on Mars and maybe a little bit later on, they actually decide to stay there?

Ellen Stofan: You know, I just think it's this incredible inspiration. And I do want to make it clear, you know, sometimes you read in the press issues around people saying, well, if the Earth gets really bad, we'll go live on Mars. No, Mars is really tough. It's irradiated by cosmic radiation and solar radiation because it doesn't have a magnetic field that protects you from space radiation like the Earth does. There's chemicals in the soil that are toxic to humans. Mars is really tough and we certainly need a scientific base there with humans, but we're not going to move large-scale numbers of humans to Mars, it's just a step too far.

I'm really looking forward to the day when we have bases of humans on Mars doing science, looking for evidence of past life. And I do think, again, if you look back to Apollo, look what humanity can achieve when we put our minds to it. And what I love about this journey, Mars, is it's very unlike the journey to the Moon that Apollo did, because all of a sudden you're not going to have just one space agency leading it, you're having space agencies from all around the world cooperating to get to Mars. You have people that look like all of us who are going to be the crews that go, not just two or three white men, and you're going to have real international cooperation and also public-private partnerships that I think make this very different, very exciting, very inspirational. And I think that idea of having all of us go to the Moon or to Mars together is really going to inspire the next generation of technologists, of people who help us make this planet more sustainable.

Nikolai Khlystov: Well, we've spoken a little bit about humans going to the Moon, humans going to Mars. I mean, there are lots of other missions that are taking place right now which are being planned for as well, pushing the horizon a little bit on the distance in our solar system. So off to Mars, we have a few more planets. There is one particular planet which is very interesting: Saturn, and it has some interesting moons, of course. And you know, one of those moons very well, Titan. Can you tell us a little bit about Titan, why you know it and what's being planned for Titan in the coming years?

Ellen Stofan: Yeah. So I worked on the Cassini mission to Titan, which was really amazing. And right now I'm a co-investigator on a mission called Dragonfly. It's going to launch in the late 2020s, around 2027. It'll get to Titan in the early 2030s and it is an octocopter. So it's basically a drone that's going to land in the equatorial, so near the equator on Titan and fly around the equatorial region. Landing, going back up, landing again, sampling the surface, understanding what it's made of.

So why is this interesting? Titan is the only satellite in the solar system that has a substantial atmosphere. Its atmosphere is mostly nitrogen, like ours. It's also the only other body besides Earth in the solar system where you have large bodies of liquid, you have rivers that flow down into those seas. So you have these incredible earth-like processes going on on the surface, which help us understand the Earth better, which is why we explore the planets. But it's also, to me, just kind of magical in a way. I spent five years working on a proposal to send a boat to one of those seas on Titan that didn't go forward. But we've got Dragonfly, which I'm really excited about now.

Why should we care about rivers and seas on Titan? And wait a minute, Saturn, how does that work? It is very cold out in the outer solar system. In fact, it's about 90 degrees kelvin on the surface of Titan. That's not water, right, at those temperatures. The rocks on Titan are actually made of water ice. That fluid that's raining down from the sky, forming the rivers and seas is actually liquid methane and liquid ethane. Basically liquid gasoline, that's what's the fluid out with those temperatures in the outer solar system. It's really interesting to say how does a river work? How do waves form on an ocean in different gravity, different fluid? We can learn more about the fundamental behaviour of how river and ocean systems work, how they exchange gas with the atmosphere and how the climate of Titan is affected over time. So super interesting on many, many scientific levels.

The other thing that's super intriguing is we've really thought a lot about life in the solar system. Right now we have one data point that's the Earth. And so we know life formed here on Earth fairly rapidly. After the Earth formed, all the planets formed about four and a half billion years ago. By 3.9 billion years ago, the conditions here on the planet had stabilised. Life evolved almost right away, simple single-celled life forms in the oceans. So we think you definitely need water. The organic molecules were actually delivered by asteroids and comets. You see amino acids in both of those, we see amino acids in interstellar clouds. You had this combination of energy, water and organic compounds, and you've got the evolution of life. When you go to Titan, you have those same organic materials — methane and ethane are organic fluids — you've got sources of energy, we know there's volcanoes on Titan, we know it rainstorms on Titan. But remember, you don't have water. So how important is water to the evolution of life? We don't know the answer to that. So Titan is a super interesting place to go to really understand what are the limits of life? Could we have weird Titan life? We don't know. We're going to go find out. And this question of life in the solar system in the universe is so important.

Nikolai Khlystov: Well, let's let's maybe talk a little bit about that and let's talk about another huge mission, huge scientific mission: the James Webb Space telescope. Share a few details, a lot of folks may have heard about it, but some maybe have not. Another telescope which has given us amazing amount of wealth of knowledge over the last couple of decades, of course, the Hubble. Maybe mention a little bit what is the difference between Hubble and the James Webb, and maybe share a few things about James Webb. Has it uncovered anything dramatically new? It's been active for just a number of months, I think, right? Do we know something that we didn't know before it went up?

Ellen Stofan: Hubble was such an amazing telescope. You know, it's still operating now. I don't even know I'm going to get the date wrong. It's like 28 years or something like that. So it's operated way beyond its lifetime, partially because it got repaired by astronauts many times. It's in a lower orbit than James Webb is, and Hubble literally rewrote what we know about the universe. So James Webb was the follow-on telescope to Hubble. They're called the Great Observatory. We have other great observatories. The difference between Hubble is it primarily looks in the visible range of light.

If you think of the electromagnetic spectrum, all those different bands of energy give you different information. It's like putting on different kinds of glasses and being able to see different aspects of the universe and how it works because processes out there are really energetic. So you're going to learn something by looking in the x-ray like the Chandra Observatory does. You're going to learn by looking in the visible the way Hubble does. The exciting thing about James Webb is it's looking in the infra-red. So that's giving you just different information, very complementary, to what we've learned from other great observatories that are up there.

The other really big and new thing about Webb is you need a really big mirror because what you're trying to do is collect light from very far away, and the James Webb Mirror is much bigger than any mirror we have ever put before in space. And in fact, it's so big that it couldn't be put into a rocket fairing — that pointy bit at the top of the rocket — without being folded up. And now you think: that's crazy, how do you fold a mirror? Not something you would normally do, right? So this is an incredibly complicated, advanced technology mirror that was folded up, launched by the European Space Agency, Ariane rocket, and put out to a place called L2, which is the second Lagrange Point, which is basically a stable orbit. So you don't have to boost it. Once you put it there, it's in good shape. Then we had to spend about a month deploying Webb. It had some incredible number of single-point failures. If any one thing went wrong, it was not going to be successful. We had to unfold all the mirrors. We had to expand this big sunshade that blocks light so that Webb can look very deep into the universe, collect that light it needs to collect. And I was so frightened.

You know, it's one of those things I worked on Webb a little bit when I was at NASA. And, you know, the hearts and souls of the engineers and the scientists go into these missions. And I knew the science that was going to come out of Webb. It was going to be like Hubble all over again, right? It's going to be rewriting textbooks for years to come. And so when it left the Earth, it was so emotional to see that spacecraft moving away from the Earth, going through the deployment. That I can tell you every time the test images came back during that phase in the spring, it was just so incredibly exciting to see it working. The deployment went basically flawlessly and the images that are coming back: you asked, are they amazing? You know, we've been in just basically test phases. We've detected carbon dioxide planets around other stars. Imaging came out where it was reimaging something called the Pillars of Creation. It's out in the star field where we're seeing a zone where planets are forming really complimentary to Hubble, really allowing us to see these planet nurseries. How do they operate? What kind of energy processes are going on? The combination of the visible light from Hubble and the Infra-Red from James Webb are really giving us new ideas about how those zones operate. Again, these images are weeks old, so this is all like still blowing our minds.

The image that was shown there with the telescope before it was launched was its first deep-field image. Hubble had a deep field image. And what you do is you look at the darkest part of the night sky and you just leave the telescope there and you collect light. So that light is coming from very far away. This always gets people super confused because the light is coming from far away, you're basically looking back in time because that light started out a very long time ago and has now finally reached the telescope. Hubble was able to look back around 100 or so million years from the Big Bang. Basically, James Webb in this first image was able to look — it didn't even look for that long — was able to look within about 40 million years of the Big Bang. It's going to get back within a few tens of millions of years. The Big Bang, we have huge questions. What did that very early time period in the history of the universe look like? Hubble had been able to show us that very early in the solar system you had a lot of galaxies forming. If you look at this new image from James Webb of that same region, the number of galaxies has gone up exponentially. So much material, so much organization of material into galaxies already. Fascinating what this is going to tell us about how the Big Bang worked, those early tens of millions of years, which I know to most people seems like a lot of time, but it's really not in the history of our 13 billion-year-old universe, how did the universe form? And we need to know those early time periods to understand that. And you can tell I'm just getting like so excited I can't even speak. These images to me are literally mind-blowing and I'm so excited about it. This telescope is, again, going to be rewriting textbooks as we go.

Nikolai Khlystov: Well, and you're giving me goosebumps just when you started talking about the James Webb, let's maybe talk a little bit about the aspect of search for life. I mean, you've spoken about James Webb looking for the carbon signatures. Maybe you can talk a little bit about how a telescope looks for signatures of life. And I'd love to ask you another question, which perhaps becomes a little bit more philosophical, but how do we know potentially there is life hundreds or thousands of light years away?

Ellen Stofan: This is such a great question because if you again, go back to that story of how life emerged on earth, water, organic molecules, sorts of energy, again, source of energy and the organic molecules, that part we think is pretty easy. It's the conditions on a planet where water can be stable on the surface or maybe some other working fluid, depending on what we find on Titan. And then those conditions have to persist because if you look at a place like Mars, Mars had the exact same conditions as Earth at around the same time in the solar system. But those conditions only persisted for about a billion years. And here we are on Earth, three and a half billion years. You know, we're chugging along right, ish. We'll come back to that later. But what we've had certainly ups and downs, you know, massive asteroid impacts, you know, minor things like that here on Earth that have endangered the long-term existence of life. The conditions were stable enough on this planet that not only allowed life to evolve, but allowed it to thrive, allowed it to become more complex all the way from single-celled organisms to us. That's tough, right, to have that long-term stability on a planet.

So as we go outward in our own solar system, we look at Mars and say, well, wow, that's the most likely place, because we know a billion years wow on Earth life was still in the ocean after a billion years, still just single celled, multicellular, lifeforms. But life could have evolved. That's plenty of time on Mars. And so that's what we're doing on Mars. We're really looking for this question of, wow, is this the second data point where we can say, all right, those conditions, again, really easy on Earth, if Mars had the same conditions, why wouldn't life have evolved there also? If it didn't, that would actually be scientifically surprising.

Then we look out at places like the moons of Jupiter and Saturn that have water under their surface Europa, Jupiter, Enceladus of Saturn. Water oceans under an ice crust. Water. Oceans. Oceans, right, sound familiar again? Right now, there's lots of missions going on. We're going to go back to Europa and look at that body. There's a lot of missions that have been proposed looking at going back to Enceladus, this moon of Saturn. We've got Dragonfly going to Titan to look at what are the limits of life. Because if we can demonstrate that life originated in more than one body in our own solar system, it makes us much more optimistic about finding life beyond Earth. And it also widens what we're looking for, right? Because right now we think of life as life as we know it. And believe it or not, people who turned this into two acronyms: life as we know it and life as we don't know it. Because now think of Titan and now think of every science crazy science fiction movie you've ever seen, or especially, you know, Star Trek with all kinds of different life forms. Why couldn't that have happened? And so when you go out looking for life beyond Earth, you really have to wonder, what is it exactly that I'm looking for?

You know, we have very definitive ideas of life here on Earth. It has metabolism, it has reproduction. It has ability to move. So we have RNA. We have DNA. So is that what we're looking for? So we have this whole list. Actually, NASA has this great site on astrobiology where we have this logic flow of what we think of life. So now if we go beyond Earth right now, what we're looking for is sort of Earth 2.0. So when we're looking at planets around other stars, we're looking for places that have water stable on the surface. We're looking for gases in the atmosphere that here on Earth are associated with life, carbon dioxide, methane, jumping all the way back to the detection of carbon dioxide in the atmosphere around the planet, around another star that James Webb detected. Finding CO2 in an atmosphere isn't proof that there's life on that planet. You can produce carbon dioxide in lots of different ways, but finding it is super interesting and makes you think, alright, now I want to look more.

Ultimately we want to detect methane, we want to detect elemental oxygen and then what we would really like to find is what we call disequilibrium. We want to find gases that are out of their chemical balance, which would tell us there's some process going on. Something is eating something and giving something off. That's metabolism. You know, if you were looking at Earth from another star, you'd actually be able to see the Earth going through seasons because it gives off big amounts of carbon dioxide and then all of a sudden it drops again. So you can see there's some sort of active process going on. That's what will be looking on as we move forward with these big telescopes. Ultimately, we want to image planets around other stars, and for that we'd be really looking for things like colour changes. Again, it's autumn here in the northern hemisphere. You've got beautiful colour out my window, so you can actually see the colour of the Earth change as we move through seasons. Those are the kinds of things we'll ultimately be looking for. But for that, we need a way bigger telescope even than James Webb, one that we'll probably have to build in space.

Nikolai Khlystov: Maybe last question on the life topic, do you think there's a difference if we were to find signs of life, say, on Mars or in Titan versus finding some kind of life signature hundreds of light years away in another star system?

Ellen Stofan: I think so, because frankly, when we find life in our own solar system, it's either going to be evidence of past life or frankly, it's going to be in this kind of single-celled multi-cell, which is crazy exciting for scientists. Does it have RNA? Does it have DNA? Those are questions I think will be profound no matter what. But I think as we move outward, looking beyond our own solar system, what we're really hoping for is could we find somewhere where there was complex life? We just lost Frank Drake recently. He was a wonderful scientist who came up with something called the Drake Equation. He tried to put into mathematical terms what's the likelihood of finding complex life, i.e. intelligent life, more or less intelligent life like us, on planets around other stars? And I think that's really tough. And we know we're not going to do it in this solar system. So as we go outward and find more and more planets, we get closer and closer to potentially finding intelligent life, which is, I think, kind of the holy grail for what humanity is curious about.

Nikolai Khlystov: Absolutely incredible. Well, there is one more mission that was just was in the news a couple of weeks ago. And that's maybe another way to bring us sort of slowly start to bring us back to Earth. It's DART [Double Asteroid Redirection Test]. So this was a relatively small mission, but with potentially huge impacts. Can you tell us a little bit more about it?

Ellen Stofan: It did have a huge impact. In fact, there was a news story this morning about how the Hubble Space Telescope is still seeing it was able to image actually the debris trail from Didymos, the satellite. So Dart was the first time we've actually really tested can we protect the Earth when an asteroid we detect that an asteroid is headed towards Earth. The history of the planets in our solar system is a history of impact. Now, they occurred really frequently in the very early history of the solar system. You can see that just by going outside at night and looking at the Moon, of all those craters on the Moon, most of them were formed during a period we called the heavy bombardment, which is about the first 502 billion years of solar system history. After that, there was much less material around because it got incorporated into planets, got cleaned out of the inner solar system, but things still happen. You had the Chelyabinsk incident, you had Tunguska, where we had basically moderate-sized rocks coming into Earth's atmosphere, knocking down trees, breaking windows. All right, just think if something like that happened in New York City. Just think of the rock were a lot bigger. Just think if it was really big and we were looking at something, the scale of what happened at the Cretaceous-Tertiary boundary where a lot of life on Earth was actually wiped out.

So, we need to be able to protect ourselves from incoming asteroids. And DART was actually a test of this. We went and slammed something into an asteroid. And you can say, well, that's just physics. Certainly, we understand, you know, you hit one body with another, what's going to happen? The problem is asteroids are messy. Some of them are made of metal. So they're really dense and really you would hit it and it might not go very far. A lot of them, though, actually a huge majority that we've been able to understand, are actually piles of rubble. This is the case with the one we hit. And so you saw this just huge amount of debris that came out, again, detectable by Hubble. So, fascinating mission — really fun.

And again, the reason we do so much in space is thinking back to this planet, which as Carl Sagan very eloquently said in his pale blue dot speech, which I always urge people to go look at, you know, the Earth is where we make our stand. Of all places we've seen, of all the places we've studied, and again, he says it much more eloquently than I am, this is the only place we've found where humans can actually live and thrive.

Nikolai Khlystov: You, as a planetary scientist, of course, refer to this, right? You studied Venus, you've studied Titan in detail. And you know what can happen if greenhouse gases take over. Could you share a little bit about what you have seen from from some of the other places in the solar system as examples? How do how do we related back to our planet, particularly now?

Ellen Stofan: I study planetary surfaces, so I look at things like volcanoes. And what we're trying to do is use other planets to help understand the Earth. Like if you are a doctor and you only have one patient, that's how it is. You're hampered when you're only studying one planet. So through comparative planetology, we can look at things like how do volcanoes erupt under different conditions, different gravity, different rock types across the solar system? Well, think of that with weather and climate. So when we look at Venus, when we look at Mars, when we look at Titan, we have planets with different climates, different gases in their atmosphere. One thing we have learned, if we've learned nothing else. Greenhouse gases warm a planet's surface. We understand that and a lot of the times when I talk to climate deniers, it's like, look, I've got Mars, I got Venus. I can tell you we understand how greenhouse gases behave. If we put all that oil, gas and coal into the Earth's atmosphere, this planet would become flat-out uninhabitable. That can't happen.

So we have the technology, we have the knowledge to be able to move beyond where we are now, which is a bad place with human-induced climate change. And the planets have helped us inform how to understand how to model planetary atmospheres, and we understand this planet's atmosphere well enough. Part of that, again, has been through space data. NASA has over 20 satellites and instruments looking at this planet. So does the European Space Agency. All of the space agencies of the world really work really closely together on Earth observations. How do we use space data for Earth to understand this planet, to model what's going to happen to it in the future, and to understand how to use those data for humanity to make sure we can feed this planet, to make sure we have water and these space data really help us move forward on that.

Nikolai Khlystov: So we spoke a little bit about exploration. And so one of the questions I have coming in is what sort of support is needed for the upcoming exploration missions from other sectors, other industries?

Ellen Stofan: You know, I think if you name an industry, there's a way that they need to support space exploration and even more important, planetary sustainability, because when you think about it, if you're going to be on a three-year mission to Mars or a long time duration on the Moon, you need a clean atmosphere, you need healthy food, you need stable pharmaceuticals that don't require refrigeration and are stable for long periods of time. You need to use the least amount of goods possible. I'm thinking of things like clothes. Wouldn't it be great — wear an outfit, you put it through a feed or you print out a new outfit to wear. Rather than having to bring three outfits with you, you bring one and constantly and recombobulate it. That's beyond my- I'm a geologist. And so this idea of living sustainably, living in a circular way rather than in a linear economy the way they do now, all of this is what you need to live on the Moon or Mars. And frankly, this is what we need to do to live on this planet sustainably. So I think there's not an industry out there that doesn't need to think of this idea of Spaceship Earth and that benefits spaceship to moon, spaceship to Mars.

Nikolai Khlystov: Ellen, one more question from the audience. In your opinion, when will we get to Mars with humans?

Ellen Stofan: You know, we could get to Mars with humans in five to 10 years easily. Again, remember that eight to nine years that it took us from Apollo when we knew nothing? It's a question of will and it's a question of resources. And so if the governments of the world decided this was important, we could be there in five to 10 years. If they decide it's not important, we'll get there in, my guess is, 20 to 40 years. That's a huge range, and I think it's really going to depend on the will to actually do this. And I think the other wild card in here is the private sector. I mean, you do have private companies like SpaceX saying we're going to go to Mars, whether the governments want to go or not. And so I think that's a wildcard factor. Does that get us there in more like that ten-year timeframe? So it's going to be interesting.

Nikolai Khlystov: A follow on to that in terms of international collaboration. We have obviously several international missions for the Moon. Artemis being one of them. We have several nations that have made it to Mars. How critical will international collaboration be for getting to Mars?

Ellen Stofan: International collaboration to me is key to absolutely everything and to me it's been a deep part of my career. There hasn't been a planetary mission I've worked on that has not been done internationally. I did my Ph.D. thesis on the Soviet data of Venus and worked very closely with scientists from the Soviet Union. So this is just to me, this is the way we operate and it's the best way. The smartest people are located all over the world. And you want Team Earth getting things done, not a team from one country, because you're going to get there faster and you're going to get there better if you go together.

I think the other issue is this is really expensive, right? And I would argue probably no one country has the ability to do this on their own. And so as we go together, we spread out the cost of it. But again, when a government puts its money into doing something really tough like going to Mars, you're investing in your economy, you're investing in technology, you move your economy forward. So, his isn't a i'm throwing this money away, which a lot of people I often get the question, you know, why aren't we spending money for Earth rather than for space? You spend money for space on Earth, and it's an investment in technology and moving us forward. And as I said, it's also helping us move forward on this idea of planetary sustainability.

Nikolai Khlystov: Let's come back to one of the earlier points of motivation, of generating this excitement, in the space sector, particularly, we're almost lacking talent. We're lacking folks coming out of different universities with the right skills. How important is it to motivate the younger generation on the different maths and sciences and other subjects that are required to go into this field and develop these rockets and develop these landing mechanisms and telescopes. How do we do a better job, perhaps, at communicating this?

Ellen Stofan: Well, you know, this is an incredible focus of ours at the Smithsonian, because to me, it's about great storytelling. You've got to inspire people. Not to be mean to teachers — my mom was a teacher, my grandfather was a teacher — but if you say, all right, we're memorising the formula of the quadratic formula, you're like, why? Am I ever going to use this? What good does it do? And at the Smithsonian, I think we do a really good job of trying to say, look at the amazing things that we do in science, whether it's exploring the planets, understanding how the Sun works. You can be a part of understanding these fundamental whys. Are we alone? How does our planet work? How does the universe work? And it's about storytelling to engage kids.

The other thing we've really been focused on, and I urge people where we've reopened half of the renovated Air and Space Museum on the National Mall, and I think you're going to see a really different Air and Space Museum than maybe the one that you went to 20 years ago. Because what you're going to see are stories about people who look like all of us, whether it's the African-Americans who helped with the Apollo programme, people like the hidden figures. We have Jackie Cochran's plane, not just Chuck Yeager plane, that she was the first woman to break the speed of sound.

If we tell stories about people who look like all of us, we're inspiring kids to say, I can do that. I can go figure this out. You know, I think one of the best-kept secrets we have in STEM, we get to have all the fun. We get to ask, how does the world work? And we go figure it out.

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