- Mars is teasing us. Humanity has been dreaming of landing on the Red Planet for over a century. And with the advent of space flight and moon landings, it seems like it should be just right around the corner. And these missions wouldn't just be for scientific exploration, which would be super awesome, 'cause we would learn about the origins of life and the formation of the solar system. They would serve to set up a permanent human presence on Mars, a colony on another world. If only we could figure out how to do it. [dramatic music] Before we launch on our first mission to Mars, let's look at the pros and cons of living on the Red Planet. Let's start with the cons, and frankly, there are a lot of cons. Mars has no air. It has less than 1% of the air pressure of the Earth, and what air there is, it's almost entirely carbon dioxide. Mars has no liquid water. There is water there, but it's locked up as ice, either underneath the surface or in the polar ice caps. We need liquid water to survive, and this makes it just so much more challenging. Next, Mars is constantly suffering bombardment of solar radiation and cosmic rays. These are high-energy particles that can break apart cells and even snip DNA itself. Without a thick atmosphere and without a magnetic field, Mars is just exposed to this deadly radiation and can increase cancer rates for any Martian colonists. Mars is far from the Earth, hundreds of millions of miles away. It would be the most distant mission we've ever sent, and it's also socially distant. Martian colonists would be the furthest human beings from Earth in, well, the entire solar system. Mars has less gravity than the Earth does. We don't know fully how to live and work and maintain our health and fitness in low-gravity environments. Our hearts shrink, our muscles degrade, our bones wither away. We don't even know if fetuses in the womb can grow straight spines without Earth's gravity. To go along with that, Mars has about half of the sunlight that Earth does. And so anything that requires solar energy, like solar power or photosynthesis, is going to be so much less efficient. Mars occasionally experiences global dust storms. The dust on Mars has been blowing for billions of years, and it's not like dust or sand you might find in a desert. It's more like a fine talcum powder that gets everywhere and occasionally coats the entire planet, blocking out the sun for months on end. Mars is also cold, really, really cold. The average temperature on Mars is negative 81 degrees Fahrenheit, and it gets as low as negative 220 degrees Fahrenheit. It's just a cold place. It's colder than the coldest places on Earth. And if that weren't enough, the soil on Mars is full of toxic chemicals that have to be filtered out before you can use it as soil to grow crops or to breathe in or to just exist in. These are all the cons. What are some of the pros of going to Mars? Why would we wanna do that? Well, who doesn't like an adventure? No, I'm serious, I'm serious. Adventure and exploration has been a part of humanity. It's in our DNA. It's something that defines our species. And going to Mars is simply the next step in a journey that we've been on for tens if not hundreds of thousands of years. And hey, Mars can offer another home. If something catastrophic were to happen to the Earth, we'd have a plan B, a planet B, if you will. And hey, going along with that, Mars has lots of empty space free for the taking. No one has a claim on Mars. No one is already living there. So it gives us a chance to colonize, to explore, to build new cities and new civilizations without eliminating existing ones. And there's tons of science to be done on Mars. Not just the history of the Red Planet, but the origins of life. Mars was once a potential home for life with liquid water and a thick atmosphere, but something stopped. Understanding what happened on Mars can help us understand the origins of life on the Earth. And lastly, my favorite reason to go to Mars, lots and lots of red. If you're a fan of the color red, well then, this planet is for you. That was very satisfying. Anyway, if Mars is so terrible, why should we even bother going there? Why don't we go to the moon? The moon, it's literally next door. It's only days away instead of months away. There are some advantages to Mars over the moon. For one, it's bigger, so it does have more gravity, and it does have water. It's frozen, but it still exists and is accessible. Among all the worlds in the solar system, Mars is the closest thing we have to Earth. So to design our mission to Mars, let's go to the chalkboard. Let's take a look at what a single mission to Mars would look like. This is our solar system. Well kind of, it's not exactly to scale. But here in the center we have our happy little sun, and here we have the orbit of the Earth and the orbit of Mars. If we want to get from Earth to Mars, we have to do some very complicated orbital dynamics. We need to rely on Newton. Isaac, Isaac? Okay, maybe he'll show up later. Actually figuring out and plotting these missions is incredibly difficult, and that's because the Earth in its orbit, it's constantly moving, and so is Mars at a different distance and a different speed. So the most efficient way to get to Mars is to wait for conjunctions, when our planets align. To sketch out a mission here, let's say we're on the Earth and we wanna send a mission to Mars. But when we're in conjunction, by the time the mission actually gets to Mars, it's not gonna be here, it's gonna be way up here. So Mars is gonna be here in its orbit. So our trajectory from Earth to Mars will look like this. And with chemical rockets, that'll take about 180 days in a weightless environment just to get to Mars. Now, you get on Mars, you land, you poke around, you scare all the Martians, you do your normal Martian business there, and you wanna get back to Earth. Well, guess what? You're not in conjunction anymore. You have to wait. You have to wait for the planets to align again. So you have to wait on Mars as it continues its year before everything lines up again. And only then can you return to the Earth, and guess what? It's another long trip. When you launch from Mars here, the Earth is not gonna be in conjunction anymore. You have to travel another 180 days to intersect and safely return to Earth. This is one of the most energy-efficient missions to Mars, and the entire mission duration is two years. That's longer than any mission we have ever had in space before. And that's just a single mission. To build a colony of permanent human presence, we need tens, hundreds, thousands of missions to the Red Planet. We're gonna have to bring a lot of stuff. I mean, oh boy, think about all the things that you surround yourself with in your daily life. Like air, we're gonna have to bring our own air to Mars or figure out how to make it there. We're gonna need communications gear so we can talk to each other and call back to home. We're gonna need a mode of transportation, not just to get to Mars, but to move around on Mars, to explore. We're gonna need storage, we need like grain silos. Is there grain on Mars? No, there's not grain on Mars, but we're gonna need silos for something eventually. We need food, we're gonna have to either bring food from Earth or figure out how to grow it on Martian soil. We're gonna have to figure out how to extract resources from Mars. We need to turn that Martian regolith into walls and ceilings and toilets and stuff, all sorts of stuff. We need utilities, we need plumbing and electrical conduits. We need ethernet cables and cell phone transmitters. We need fuel to power everything. We need water, and yeah, there's plenty of water, but it's frozen, so we need to heat it up first. We need habitats, we need a place to live. We need a room and a dining room and maybe even a foyer. But we need all this stuff. We've begun to solve some of these challenges. We've started thinking about how to knock some of these items off the list so that we can build up a permanent human presence. And one very interesting idea relies on something called the Sabatier process, named after a French chemist. Did I say the Newton process? No, I didn't. Isaac, you're late, you were supposed to be on the other side, thank you. What we're gonna talk later, okay? Anyway, the Sabatier process, let me show you. It's a very simple chemical reaction where if you take carbon dioxide, which Mars has plenty of carbon dioxide, that's for sure, and you add some hydrogen, which we can take along with us, it's a relatively easy to transport fuel, put it under a lot of pressure at some high temperatures, you get methane, which is a fuel, and as a bonus, some water. So one chemical reaction can transform something that's already present on Mars into a source of fuel and water. That's not so bad. This doesn't solve all the problems, but it does start to chip away at them. But to dig into the technology that we are developing today to build a human colony on Mars, we're gonna need to talk to an expert.

- My name is Eric Berger. I am the Senior Space Editor at Ars Technica and author of a recent book called, "Liftoff" about the origins of SpaceX.

- So what are the next steps that we need in technology, in engineering and understanding to enable a Mars mission? Could we do it tomorrow if we wanted to?

- You could do it tomorrow if you didn't mind that the astronauts died. But if you wanted them to live, we could not do it tomorrow. When you think about it, really the first step toward going to Mars is the transportation system. You need a way to get four, six, eight or more people off of the planet Earth to survive a six-month journey to Mars and then to get them safely down to the surface of Mars. And then if you wanna bring 'em back, you've gotta figure out how to launch a rocket from Mars, rendezvous with maybe a spacecraft in Mars orbit and then come back to Earth and then land on Earth. We've never sent a really large spacecraft to Mars. Obviously, the biggest one is about metric ton, and we would need to land something in the order of 20 to 30 tons on the surface of Mars. So you really need to solve the transportation system problem first. And we don't have that, NASA doesn't have that. No one really has that.

- What about landing on Mars? We've developed all sorts of interesting contraptions. Like there was the giant bouncing ball. There are these sky cranes. How do we land a, like you said, a multi-ton vehicle on the surface of Mars? What kind of technology do we need to develop?

- The key technology is propulsive landing. We've never really done that on Earth. When the space shuttle came back to Earth, it was a glider. When our capsules come back to Earth, they're under parachutes. We launch under propulsion, but we don't really land under propulsion. Mars has a much thinner atmosphere, obviously. And so to slow down such a large, massive spacecraft coming to Mars, you need some kind of propulsive landing technology, and that's probably some kind of thruster. But it's very much sort of theoretical and not actually real.

- In your estimation, and this is just your personal Eric Berger take, how long until the first human steps foot on Mars?

- I'm 48 years old, Paul, and I'd love nothing more than to see humans walk on Mars in my lifetime. It's just a technological leap with the existing rocket technology we have. It's a half-trillion dollar mission at least. And it requires decades sort of work to build up to it. Realistically, I think even SpaceX, we just talked about sending humans to Mars in the 2020s. I don't see that as viable, but within 10 to 15 years, maybe.

- All right, all right. Let's fast forward a couple decades into the future. You're playing with your grandkids, you're watching the TV, you're watching this Mars mission play out. What does it look like step by step? How many launches does it take to get the required equipment into orbit and on Mars? Just what does that whole scenario look like?

- We went to the moon with the Saturn V rocket, and that rocket was just big and burly enough to carry everything we needed to set several tons down on the surface of the moon and get two astronauts there and back. A single rocket ain't gonna do it for Mars. So even if you have sort of the most powerful rocket that NASA's building, which would be the Block 2 variant of the SLS rocket, you'd probably need six to eight of those launches to not just establish your ship that's gonna go to Mars, but to fuel it. That's kind of like why when Elon Musk or Jeff Bezos or Relativity or these other companies, their plans sort of incorporate reuse from the beginning, because you're gonna have lots of launches to do this. And if you're spending so much money launching an expendable rocket, you just can't afford to go anywhere.

- Let's fast forward even a few more decades, 'cause we do wanna push the edge here, and look at Mars colonization. It's certainly plausible that the first missions to Mars will be you'll go and you'll come back. What would it take to set up a semi-permanent status where there's rotating crews in and out, like the International Space Station, like our deep Antarctic research stations, what kind of infrastructure would it take to get there?

- I actually had an interesting conversation with Elon Musk about this. The question was, what would it take to build a self-sustaining settlement on the surface of Mars? It would take one million metric tons of stuff, propellant, the 3D printers, the stock for the 3D printers, food, agriculture, domes, wherever you're gonna live, all of it, to get to the point where you could have all that on Mars and those people could then survive without intervention from Earth. So one million metric tons, if you think about that, it takes a very large rocket and a whole sort of sophisticated spacecraft. The Curiosity mission was what, a couple billion dollar mission to get to Mars? And that Rover was one ton. That's the challenge we're talking about, sending one million Perseverances or Curiosities worth of mass to Mars. It's an enormous challenge.

- And how many people would that support?

- I would think that would be dozens or hundreds. I mean, it would be like a growing, thriving colony. But there are basic questions, right? We don't know if humans can procreate in microgravity. We don't know if they can procreate in the one-third gravity on Mars. How would humans evolve if they were living all or most or all their lives on Mars? These are great unanswered questions. I'd love to answer them one day.

- Is there a future for humanity on Mars?

- I'm of the group of people who think that the destiny of humans is to get out there and live among the stars. It's very clear that there are no planets in the soar system or moons remotely close to Earth in terms of the suitability for humans. It is a Garden of Eden, literally. And presumably, there are planet like Earth or somewhat like Earth around other stars. And we'll get there one day. But to do that, we've gotta take the first step. And I think if you look around the sources of Mars, for all of its flaws, and there are many, as you well know, offers the best bet. Probably most importantly, it's fairly close. Six months is a long time to get there, but that's doable. It's not three years to a moon around Jupiter or something like that, it's closer. It's far from perfect, but you gotta start somewhere, and that's probably the best place to start.

- This was a delight of a conversation. I really appreciate your time.

- Thank you, Paul.

- That's all short-term visits. For long-term habitation, we have to face a massive problem. How do we turn this into this? This is a process called terraforming, and it involves beefing up the Martian atmosphere. But we need a lot of atmosphere. We need at least 10 times the current Martian atmosphere for water not to boil at body temperature. And we need at least 20 times the pressure to make it pleasant to walk around on the surface without a suit. So we need to bulk up that atmosphere, what do we got? The best things we have on Mars are the water and carbon dioxide locked up in the soil and at the poles. But unfortunately, there isn't enough, even if we liberated all of it and put it all all into the atmosphere. It would only raise the air pressure by like one or two or maybe three times its current level, which isn't enough. So we have to import an atmosphere from somewhere else. We have to crash land comets from the outer solar system onto the surface of Mars. That kind of process is going to take generations, and we have to fight an even bigger battle, because Mars doesn't have a magnetic field. The Earth's magnetic field protects the atmosphere from the bombardment of solar radiation, so we have to introduce an artificial magnetic field around Mars in order to keep that atmosphere locked in. For generations, Martian colonists are going to have to live underground like some sort of Martian mole people. Oh, and you got the note from my manager, right, that I'm not wearing the mole costume? Okay, got it. That's long term. Right now we're focused on stepping one foot on Mars and then 10 and then a hundred, slowly building up to have a permanent human presence. There's no physics reason preventing us from inhabiting Mars, it's a matter of technology and engineering and patience, and most importantly, money. But there's no reason why we can't eventually be on Mars. Humanity will have a presence on Mars. Well, I'm not going.