So how do we figure out how to take you to Mars and create a self-sustaining city? A city that it is not merely an outpost, but could become a planet in its own right. I think in the very beginning it may be similar to an Antarctic station, that's nice but on Mars we should be aiming for a real civilization. To establish life on Mars ultimately means taking at least tens of thousands of people, perhaps ultimately millions of people and millions of tons of cargo, because we’ve gotta recreate the industrial base of Earth. There needs to be some sort of architecture for establishing a city, which means huge numbers of people, and ultimately millions of tons of cargo. How do we do that?
You really need a fully reusable Mars Transportation System, which is yet a more difficult step than creating a fully reusable Earth system. I was really worried that that would not be possible, but I became convinced that it actually is possible. Which made me very happy actually. In fact, I think Talulah was there when I was pacing around the bedroom late at night trying to see if this would work. Now, I could be deluded, but unless I'm deluded I think we've got something in mind that would be a solution that would work.
It really comes down to an economic question. Which is - there's some economic activation energy, a cost-per-unit-mass to the surface of Mars at which point we'd have a self-sustaining civilization there, but beyond which we would not. It really comes down to a cost: What cost does a trip to Mars have to be in order for it to be a self-sustaining reaction? There is definitely some amount of money that has to be spent establishing a base on Mars, basically getting the fundamentals in place. Call it the activation costs of a Mars base. That was true also of the English colonies. It really took a significant expense to get things started. You really didn't want to be part of Jamestown. It took quite a bit of effort to get the basics established before the subsequent economics made sense.
The key to establish a self-sustaining Mars civilization is getting the cost per unit/mass low enough that there is an intersection of sets, the set of people that is interested in moving to Mars, and a set of people that can afford to move to Mars, inclusive of government aid. I mean right now we can't even get one person to Mars. I mean, right now it's like - I don't know, the last NASA estimate was $500 billion, and that was during Bush the first. So, I would imagine that today's estimate is a trillion. We're not going to go spend a trillion dollars on sending four people to Mars. Right now the cost of going to Mars is beyond what can be afforded so that's why no-one is going to Mars.
Using traditional methods, you know if you've taken a sort of Apollo-style approach, an optimistic class number would be about $10 billion a person. For example, in the Apollo program the cost estimates are somewhere between $100 to $200 billion in current-year dollars, and we sent 12 people to the surface of the Moon. Which was an incredible thing and probably one of the greatest achievements of humanity, but that's a steep price to pay for a ticket. You can't create a self-sustaining civilization if the ticket price is $10 billion a person.
Ultimately, in order to establish a colony I think you've got to get the cost down to maybe half a million or less, per person. The key I was trying to figure out was, with volume, is it possible to get the cost of moving to Mars down under half a million dollars, which I think is - no-one can argue about the exact threshold, but I think that is about the threshold which enough people would save up money and move to Mars. It's up to debate about how much that might be but I think at a personal level that would be enough of an intersection of sets of people who can afford to move to Mars, and people who want to move to Mars. If those two coincide then there will be a colony, otherwise there will not be a colony. To put that in concrete terms, it needs to be at least a half a million dollars or less to move to Mars, I think. Ideally much less, you know, but if it's much more than that then there probably won't be a colony. That's the basic idea.
I sorta started back from the half a million dollar point because in order for Mars to become a self-sustaining civilization the ticket price has to be low enough that if someone were to work hard and save up then most people in advanced countries after, say, their mid-40s or something like that, could put together enough money to make the trip. I thought, a half a million dollars, that's a middle class house in California, basically. Something on that order, that's about the right order of magnitude, and then, working backwards. If people could pay half a million dollars to move to Mars, sell all their stuff on Earth because you don't need it, then you could move to Mars, then I think that could work. That's basically the net worth of a roughly middle income earning person after about 25 years in the United State roughly half a million dollars. In fact, it's kinda hard to buy a house in southern California for half a million dollars in a lot of neighborhoods. So I think at roughly that level is where it works. That's where we've got to get to, and my calculations show that it should be possible. In fact, it is possible... according to me.. but there's a great deal of work that has to occur to make it a reality. If we can get the cost of moving to Mars to be roughly equivalent to a median house price in the US, which is around $200,000, then I think the probability of establishing a self-sustaining civilization is very high. I think it would almost certainly occur.
Not everyone would want to go, in fact, I think a relatively small number of people from Earth want to go, but enough would want to go and could afford the trip that it would happen. I mean, that's how America got created, basically. That's sort of the key threshold for it to become a self-sustaining.. 'colony' if you will. Kind of like the English colonies in the Americas, which started out with a lot of sort of basically rich people and the British government sponsoring people to go over, but eventually, you know, anyone could go over.
I think there's plenty of people who will sign up for a one-way trip to Mars. It'd certainly be enough, but I think the question is, is it a one-way mission and then you die, or is it a one-way mission and you get resupplied? that's a big difference. I think it ends up being a moot point because you want to bring the spaceship back. These spaceships are expensive okay, they're hard to build. You can't just leave them there. Whether or not people want to come back or not, is kind of - like, they can just jump on if they want, but we need the spaceship back. I mean, it'd be kind of weird if there's this huge collection of spaceships on Mars over time. It'd be like, maybe we should send them back - no, of course we should send them back. Particularly if we want to have a colony of some kind that's of significant size. So they can come back if they don't like it, of course. You get a free return ticket, they get a free return ticket if they don't like it. Sort of aspirational it'd be a round trip. So you are not sort of trapped there. I do think we will want to offer round trips because a lot more people would be willing to go if they think that if they don't like it they can come back.
When England was establishing colonies in America, they needed the ships to return. If the ships were just one-way they would run out of wood in England. So anyone who wants to return can just jump on. If people are going to go there to settle, then hey, you don't need a return ticket. When people came over here from England in the beginning I don't think they bought return tickets.
Anyway, if we can get to some sort of point where the cost of a ticket to Mars is less than, say, the average house price in California, then I think there's some number of people who would be willing to sell their house and all their stuff and go to Mars. At least enough to get things started. I think you'd have enough people who would buy a ticket and would move to Mars to be part of creating a new planet and be part of the founding team of a new civilization.
The world on the whole is getting richer, so I think even if only 1 in 10,000 people decided to go that’d be enough, or every 1 in 100,000. You'd obviously have to have quite an appetite for risk and adventure, but there's 7 billion people on Earth now. There will be probably 8 billion by the mid point of the century, so even if one in million people decided to do that, that's still 8,000 people, and I think maybe more than one in a million people would decide to do that. That I think is a reason to feel good about the possibility of life on Mars. I think really, what matters is finding a way to do it.
So there is that basic investment and we'll need to gather the money to do that, but then once there are regular flights, that's where I think there would be enough people that would buy that - they'd just sell their stuff on Earth and move to Mars - to have it be a reasonable business case. You need the transport link and what SpaceX is trying to establish is the transport link and create an environment for entrepreneurs on Mars to flourish. I think it gets to the point where almost anyone if they saved up and this was their goal they could ultimately save up enough money to buy a ticket and move to Mars. Mars would have a labor shortage for a long time, so jobs would not be in short supply.
In the beginning you'd go with a smaller number of people and you'd have a higher proportion of cargo and emergency equipment and that kind of thing. Once you really got rolling, you'd increase the number of people on the flight because you'd have supplies there. So you wouldn't need to worry about carrying with you all the supplies for the journey there, the stay on the surface, and coming back. Initially you start off with maybe a handful of people, less than 10, just trying to give orders of magnitude here, but then you'd go to 100 or more in steady state down the road.
It is a bit tricky, because you have to figure out how to improve the cost of trips to Mars by 5,000,000%. This is just not easy, I mean it sounds like virtually impossible, but I think there are ways through it. This translates to an improvement of approximately four-and-a-half orders of magnitude, each order of magnitude is a factor of 10. These are the key elements that are needed in order to achieve a four-and-a-half order of magnitude improvement. Most of the improvement would come from full reusability, somewhere between two and two-and-a-half orders of magnitude. Then the other two orders of magnitude would come from refilling in orbit, propellant production on Mars, and choosing the right propellant.
I'm gonna go into detail on all those. Full reusability is really the super-hard one. It's very difficult to achieve reusability for even an orbital system and that challenge becomes substantially greater for a system that has to go to another planet. You definitely need to have full reusability because even partial expendability would kill that price. The difference between reusability and expandability in any form of transport if they were single-use almost no one would use them. They'd be too expensive. But with frequent flights you can take something like an aircraft that costs $90 million, and if it were single-use, you'd have to pay half a million dollars per flight, but you can actually buy a ticket on Southwest right now from LA to Vegas for $43 — including taxes. I mean, that's a massive improvement right there, it's showing a four-order-of-magnitude improvement. Now this is harder. The reusability doesn't apply quite as much to Mars, because the number of times that you could reuse the spaceship part of the system is less often because the Earth-Mars rendezvous only occurs every 26 months. With the spaceship you say, "well, how long is it gonna last?" Well, maybe 30 years. So that might be 12, maybe 15 flights of the spaceship, at most. So you really want to maximize the cargo of the spaceship and reuse the booster and the tanker a lot.
You get to use the spaceship part roughly every 2 years. Mars is only on the same sort of rough quadrant of Earth, roughly 6 months every two years. By same I mean sort of offset, like a transfer quadrant. If you can get the ship to and from Mars inside that 6 month window you get to use it twice as often. So there’s actually a lot of merit to get to Mars under 3 months. Depending upon which Earth-Mars rendezvous you're aiming for the trip time, at six kilometers per second, departure velocity can be as low as 80 days. Then, over time, I think we'd obviously improve that and ultimately I suspect that you'd see Mars transit times of as little as 30 days in the more distant future. It's fairly manageable, considering the trips that people used to do in the old days. They'd routinely take sailing voyages that would be 6 months or more.
Essentially what happens is, the rocket booster and the spaceship take off and load the spaceship into orbit. The rocket booster then comes back — it comes back quite quickly, within about 20 minutes — and so it can actually launch the tanker version of the spacecraft, which is essentially the same as a spaceship, but filling up the unpressurized and pressurized cargo areas with propellant tanks. They look almost identical, this also helps lower the development costs, which absolutely will not be small. Then the propellant tanker goes up multiple times, anywhere from three to five times — to fill the tanks of the spaceship in orbit. Then once the spaceship tanks are full, the cargo has been transferred, and we reach the Mars rendezvous timing, which as I mentioned is roughly every 26 months, that's when the ship would depart.
It actually makes sense to load the spaceships into orbit, because you've got 2 years to do so, and then make frequent use of the booster and the tanker to get really heavy reuse out of those. You get to use the booster and the tanker as frequently as you'd like, that's why it really makes a lot of sense to load the spaceship into orbit with essentially tanks dry, have it have really quite big tanks that you then use the booster and tanker to refill while it's in orbit, and maximize the payload of the spaceships so that when it goes to Mars you really have a very large payload capability.
Refilling in orbit is one of the essential elements of this. Without refilling in orbit, you would have a half-order of magnitude impact, roughly, on the cost. So not refilling in orbit would mean a 500%, roughly, increase in the cost per ticket.
So you send the spaceship up to orbit, you tank it or refill it until it has full tanks, the ship travels to Mars, lands on Mars, gets replenished, and then returns to Earth.
Now over time there would be many spaceships. You would ultimately have I think upwards of 1,000 or more spaceships waiting in orbit. So the Mars colonial fleet would depart en masse, kind of ‘Battlestar Galactica’ — if you've seen that thing, it's a good show — so a bit like that.
Having the atmosphere, you can use atmospheric breaking as well. And Mars has lower gravity than Earth, you do not need a booster. So you can go all the way from the surface of Mars to the surface of Earth just using the ship. Albeit, you need to go to a max payload number of about twenty to fifty tons for the return journey to work, but it's a single stage all the way back to Earth, similar to the Moon. But the tricky thing with Mars is we do need to build a propellant depot to refill the tanks and return to Earth. For Mars you will need local propellant production. It'd be pretty absurd to try to build a city on Mars if your spaceship just kept staying on Mars not going back to Earth. You'd have this like massive graveyard of ships., you’d have to like do something with them. It really wouldn't make sense to leave your spaceships on Mars, so producing propellant on Mars is very obviously important. You really want to build a propellant plant on Mars and send the ships back, and Mars happens to work out well for that. The key point being that the ingredients are there on Mars to create a propellant plant with relative ease, because the atmosphere is primarily CO2, and plenty of water ice, there's water ice almost everywhere. You've got the CO2 plus H2O to make methane, CH4, and oxygen O2, using the Sabatier reaction. With H2O and CO2 you can do CH4 methane and oxygen, O2, and bingo, you can replenish propellant. Now, you can do this either with hydrogen, or with methane.
Picking the right propellant is also important. Think of this as maybe there's three main choices, and they have their merits. Kerosene or rocket-propellant grade kerosene, which is also what jets use. Rockets use a very expensive form a highly refined form of jet fuel, essentially. It helps keep the vehicle size small, but because it's a very specialized form of jet fuel it's quite expensive. The reusability potential is lower. Very difficult to make this on Mars because there's no oil. So really quite difficult to make propellants on Mars, and then propellant transfer is pretty good but not great.
Hydrogen, although it has a high specific impulse is very expensive. Incredibly difficult to keep from boiling off because liquid hydrogen is very close to absolute zero as a liquid, so the insulation required is tremendous, and the energy cost on Mars of producing and storing hydrogen is very high.
For a while, we were sort of going down the hydrogen path, and I was looking at the numbers and you get to roughly equivalent delta-v with methane or hydrogen.
We looked at the overall system optimization, and it was clear to us that methane actually was the clear winner because of the better mass fraction of the methane system. Then you combine that with the fact that methane is much easier to deal with, it's not a hyper-cryogen, and it doesn't have the wiggly hydrogen molecule that likes to get into all sorts of unpleasant places and induce metal embrittlement, and create invisible high temperature fires and that kind of thing. We think methane is actually better, on, really, almost across the board. We started off initially thinking that Hydrogen would make sense, but we ultimately came to the conclusion that the best way to optimize the cost-per-unit mass to Mars and back is to use an all-methane system. The cheapest fuel is methane, technically a deep-cryo methalox. Actually, with a properly designed methane engine, a staged combustion engine with decent combustion efficiency in the 99% range and reasonable area ratio, 380 /sp is quite achievable. The Russians, in ground tests, have achieved 380 /sp. So this is clearly an achievable number. That's the direction we're thinking of going, for that.
Those are the four elements that need to be achieved. Whatever architecture, whatever system is designed, whether by SpaceX or anyone, we think these are the four features that need to be addressed in order for the system to really achieve a low cost per ton to the surface of Mars.
In the long term you can use solar power to extract CO2 from the atmosphere combine it with water and produce fuel and oxygen for the rocket. So the same thing that we're doing Mars, we could do on Earth in the long-term.
I guess the Moon is also a potential place for propellant depots, more water being found on the Moon. Yeah, it's in like, permanently shadowed craters. It's pretty chilly in there but you could mine the Moon potentially for water, and you could have propellant depots on the Moon. I'd liken it to when the early colonies in the Americas were being established and the early voyages of discovery. You kinda want to go there and then if it turns out that having way stations makes that trip more efficient over time, then those people will build those stations. As soon as you've got that destination, you've got the forcing function, then you'll see people do whatever seems sensible to make that better.
When there's a lot of traffic between Earth and Mars I would expect there'd be some large space cruiser that's circulating between Earth and Mars. And you just take a small shuttle craft up to the space cruiser if you will, and the space cruiser gets refueled from Earth or from Mars. But that's a long term optimization and it would be driven by a lot of traffic occurring between the two planets. To do that, you need really big rockets launching a lot, obviously in order to fit 100 people or there about in the pressurized section, plus carry the luggage and all of the unpressurized cargo, to build propellant plants and build everything we need to carry a lot of cargo. You want something that is pretty big, you know, because if you're going to have to spend a lot of months in it, it can't be the size of a minivan. The crew compartment or the occupant department is set up so that you can do zero-g games, you can float around, there'll be like movies, lecture halls, you know, cabins, a restaurant — it will be, like, really fun to go. You're gonna have a great time.
A round trip to Mars, with 6 months there, 18 months on the surface and 6 months back, two and a half years, you want a little room. I would shudder to think of doing that in Dragon. You'll come back batty, if you come back. I mean, in order to make it appealing, and increase that portion of the Venn diagram of people that actually want to go, it's gotta be really fun and exciting and it can't feel cramped or boring.
I think at least 100 people per trip is the right order of magnitude. If we say, like, the threshold for a self-sustaining city on Mars or civilization would be a million people, and you can only go every 2 years, and if you have 100 people per ship, that's 10,000 trips. 10,000 flights is a lot of flights, so you really want to ultimately think on the order of 1,000 ships. It will take awhile to build up to 1,000 ships. I think if you say when would we reach that million-person threshold from the point at which the first ship goes to Mars, it's probably somewhere between 20 to 50 total Mars rendezvous. It's probably somewhere between maybe 40 to 100 years to achieve a fully self-sustaining civilization on Mars.
I think we actually may end up expanding the crew section and ultimately taking more like 200 or more people per flight in order to reduce the cost per person. You really need something quite large in order to do that. The vehicle that we’re proposing would do about 550 tons, and about 300 tons in reusable mode. That compares to Saturn Vs max capability of 135 tons. The thrust is quite enormous. We're talking about a liftoff thrust of 13,000 tons. The main job of the booster is to accelerate the spaceship to around 8,500 kilometers an hour. For those that aren't as familiar with orbital dynamics, really it's all about velocity and not about height, that's the job of the boosters. The booster's like the javelin thrower, so it's gotta toss that javelin, which is the spaceship.
In the case of other planets though which have a gravity well that is not as deep, so Mars, the moons of Jupiter, maybe even Venus, Venus will be a little trickier, but for most of the Solar System you only need the spaceship. You don't need the booster if you have a lower gravity well, so no booster is needed on the Moon or Mars or any other moons of Jupiter or Pluto, you just need the spaceship. The booster is just there for heavy gravity wells.
It will be quite tectonic when it takes off. It does fit on a pad 39A, which NASA has been kind enough to allow us to use, where they somewhat oversized the pad in doing Saturn V. as a result we can actually do a much larger vehicle on that same launchpad. In the future we expect to add additional launch locations, probably adding one on the South coast of Texas.
We're also getting quite comfortable with the accuracy of the landing. If you've been watching the Falcon 9 landings, you'll see that they're getting increasingly closer to the bull’s-eye.
On arrival the heat shield technology is extremely important. We've been refining the heat-shield technology using our Dragon spacecraft, and we're now on version three of PICA, which is "phenolic impregnated carbon ablator" and it's getting more robust with each new version, with less ablation, more resistance, less need for refurbishment. The heat shield's basically a giant brake pad. It's like, how good can you make that brake pad against extreme reentry conditions, and minimize the cost of refurbishment, make it so that you could have many flights with no refurbishment at all.
I think the whole sort of interplanetary human flight thing being a danger to human beings is somewhat overblown because, clearly, we sent people to the Moon, and that's deep space. I think it won't be too bad. We know that people can survive in deep space because the astronauts that went to the Moon lived long lives and were none the worse, we've not seen any premature deaths, really, of people that have gone to the Moon. Really it's just a question of how long can you be in deep space, and there's a certain damage rate per day which is then offset by your body's ability to repair that damage. We also know that people can live in zero-g for long periods of time - I think the record is almost two years or something like that. I think the verdict is in with respect to long term existence in space. There were plenty of cases where it was 6 months to a year, which is the journey time to Mars. You'll need to exercise along the way to make sure you don't have muscle or bone atrophy, but I think it will be okay. People have actually shown that they can live for over year in zero gravity. Your bones do get a little thinner but they come back. I think spending 3 to 6 months zero gravity is not a problem.
Doing a six month journey you're going to have some slight increased risk of cancer but, from what I've seen, sort of a back of the envelope analysis, that increase in cancer is less than if you smoked on the way there. Although smoking is quite bad, I have to say.
There is one thing that people should be concerned about, which is solar flares, and shielding against solar radiation, solar storms. This is often thought about in the wrong way, where people say, oh, you need to have like 20 feet of water or whatever it is to shield against a serious solar storm, and they say, oh, you need to have a sphere of water around you, and that sphere of 20 foot water would be ridiculously expensive, or ridiculously heavy. Sometimes that problem is stated as if you need several meters of water to shield yourself and then somebody does the calculation for the volume of a sphere and that ends up being some enormous quantity of water. But you don't need that, you can just have a column of water pointed at the Sun, and make sure that you're mostly in front of that column and you should be okay. That'd make much more sense, and then you've gotta have water anyway, so it doesn't end up being a big deal. I don't think it's a huge show stopper and we'll figure out ways to make it better and better over time. I don't think the journey there is - there's no show stoppers there but over time we will find ways to improve it, and reduce the risk of cancer, and that sort of thing, and reduce the journey length as well. But really fundamentally we need to get there. If we can't get there it's all like academic, so we need to get there. Once you're on Mars you obviously cut your radiation in half just because you got the planet shielding you and there is at least some atmosphere. I think what you can construct overtime is a magnetic field to deflect high energy particles.
If you have a low energy trajectory, like a minimum energy trajectory, Mars is about 6 months. I think that can be compressed down to about 3 months, and it gets exponentially harder as you go lower than that - 3 to 4. It's important to actually be at that level because then you can send your spaceship to Mars and bring it back on the same orbital synchronization. You've got to be able to go there and back in one go. That's important for making the cost of traveling to Mars an affordable amount.
I'm hopeful that the first human mission to Mars is actually some collaboration of private industry and government, but I think we also need to be prepared for the possibility that it has to be just commercial. That may take longer because it'll require marshaling more resources. I want to prepare for a scenario where either path is possible. Basically, it needs to happen one way or another, that's the important thing. I'm not dogmatic as to how it occurs, just let it occur.
I'm hopeful there will be multiple colonies on Mars. There's certainly - from a SpaceX standpoint we don't mean to do anything on an exclusionary basis, we're just trying to get there. We'd love to have that debate. Is it too American? okay, maybe, but we've got the base on Mars, who cares. I think if there was an American base on Mars it would certainly prompt other countries to want to establish their own base on Mars too. I do think it would be better to have competition than cooperation. Yes, I think we'd be better off with competition rather than insisting - like, in the Space Station. We got the international Space Station, but when governments are all forced to go in lockstep it tends to not make things go faster. We want some sort of positive competitive element, I think. We don't want people going to war or anything, just some positive competitive element like the Olympics. If people compete hard and it's good sportsmanship and everything, then the net result is better than if ... like if there was no competition. Olympics with no competition wouldn't make any sense. So I think some positive competitive thing would be better, and we should definitely not insist that all countries go at the same pace, or some collection of countries go at the same pace, that would slow things down dramatically and maybe not even happen.
The thing that really matters is being able to establish a self-sustaining civilization on Mars. Beats the hell about of being a single planet species. For that I don't see anything being done except SpaceX, honestly. That's not to say SpaceX will be successful, but I don't see anyone even trying. I think long term China is a serious competitor. If you look at Russian rocketry, since the fall of the Soviet Union, there's really been no significant developments. The technology has barely progressed. No new rockets have launched since the fall of the Soviet Union, so obviously what that means is that as soon as that technology level is exceeded then they're rendered redundant and they have no ability to compete, and I think that is what's likely to occur with the Russian launch industry. I'm quite confident we can take on China. Maybe I'm overconfident, but I'd rather bet on us than China. Could be famous last words.
The basic game plan is we're going to send a mission to Mars with every Mars opportunity from 2018 onwards, approximately once every 26 months. We'd start off by sending a mission to Mars where it would be, obviously, just landing on rocky ground or dusty ground. The first launch will be robotic anyway. In terms of having some meaningful number of people going to Mars, I think this is potentially something that can be accomplished in about 10 years, maybe sooner, maybe nine years. I need to make sure that SpaceX doesn't die between now and then, and that I don't die, or if I do die that someone takes over who will continue that.
We are establishing cargo flights to Mars that people can count on for cargo. Our goal is to try to make the 2022 Mars rendezvous. That's not a typo, although it is aspirational. I think if things go like plan we should be able to launch people in 2024 and arrival in 2025.
We've already started building the system. The tooling for the main tanks has been ordered, the facility is being built, we will start construction of the first ship around the second quarter of 2018. I feel fairly confident that we can complete the ship and be ready for a launch in about five years. Five years seems like a long time to me. So then in 2024 we want to try to fly four ships, two cargo and two crew. The goal of these initial missions is to find the best source of water, that's for the first mission, and then the second mission, the goal is to build the propellant plant. We should, particular with six ships there have plenty of landed mass to construct the propellant depot, which will consist of a large array of solar panels, a very large array, and then everything necessary to mine and refine water, and then draw the CO2 out of the atmosphere, and then create and store deep-cryo CH4 and O2. Then build up the base, starting with one ship, then multiple ships, then start building out the city, then making the city bigger, and even bigger. Over time terraforming and making it really a nice place to be. The trickiest thing, really, is the energy source, which we think we can do with a large field of solar panels.
Then to give you a sense of the cost, really the key is making this affordable to almost anyone who wants to go. We think, based on this architecture, assuming optimization over time, the very first flights would be fairly expensive, but the architecture allows for a cost-per-ticket of less than $200,000, maybe as little as $100,000 over time, depending upon how much mass a person takes. We're right now estimating about $140,000 per ton to the surface of Mars. If a person plus their luggage is less than that, taking into account food consumption and life-support, then we think that the cost of moving to Mars ultimately could drop below $100,000.
What about beyond Mars? As we thought about this system, and the reason we call it a system because generally I don't like calling things systems because everything's a system including your dog, is that it's actually more than a vehicle. There's this rocket booster, the spaceship, the tanker, and the propellant plant, the in situ propellant production. If you have all of those four elements, you can actually go anywhere in the Solar System by planet-hopping or by moon-hopping. By establishing a propellant depot in the Asteroid Belt or on one of the moons of Jupiter you can make flights from Mars to Jupiter no problem. In fact, even without a propellant depot at Mars you could do a flyby of Jupiter. Establishing a propellant depot on let's say, you know, Enceladus or Europa, or any — there's a few options — and then doing another one on Titan, Saturn's moon, and then perhaps another one further out on Pluto, or elsewhere in the Solar System. This system really gives you freedom to go anywhere you want in the greater Solar System. You could actually travel out to the Kuiper Belt, and the Oort Cloud, provided we have filling stations along the way. This means full access to the entire greater Solar System. It'd be really great to do a mission to Europa, particularly.
Yep, that's how things are sort of progressing, we'll keep going until we ultimately have the capability to go to Mars, and not just get to Mars, but do so in a manner with substantially better economics then are predicted today. I do think going to Mars is definitely going to be hard and dangerous and difficult in probably every way you can imagine, so certainly if you care about being safe and comfortable, going to Mars would be a terrible choice.