Colonizing Mars: A Critique of the SpaceX Interplanetary Transport System
thenewatlantis.com
thenewatlantis.com
>Following the example of colonial America, let’s pick as the affordability criterion the property liquidation of a middle-class household, or seven years’ pay for a working man (say about $300,000 in today’s equivalent terms), a criterion with which Musk roughly concurs. Most middle-class householders would prefer to get to Mars in six months at the cost equivalent to one house instead of getting to Mars in four months at a cost equivalent to three houses.
Colonization of America was extractive. You send colonists and they survive on their own and even pay taxes and you get products back. That's not what would happen on Mars. There is nothing so valuable that it would be worth carrying back to Earth. At the same time it would take huge amount of money to support high-tech colony in Mars until it can support itself.
I imagine that the cost of moving people would be insignificant compared to the "colonization kit" that would enable the colony to become self sufficient. Developing that kit would probably cost more than all technology needed to move people to Mars. Just imagine the amount of technology transfer needed to build and maintain maintain systems for breathable air (air tanks, seals, valves, inspection equipment, instrumentation, automation electronics) without help from the Earth. Until Mars settlers can build things in-house, they need constant economic support from the earth.
ps. We don't even know how to sustain biosphere in closed environment yet.
>Until Mars settlers can build things in-house, they need constant economic support from the earth
This is where digital manufacturing (CNC, laser cutting, 3D printing) actually makes sense. You go with the base materials and blueprints, and you can survive without transferring goods. You manufacture on-demand, and the blueprints can change based on feedback/results. Mars SHOULD have a prototype culture, the same as with explorers. With engineering/research help from earth, a fab lab on mars would be incredibly valuable. Science the shit out of it!
(And probably the transportation cost will be still high enough to make it mot profitable.)
Nobody is talking about using Mars as a manufacturing base to transport to Earth, it's all about creating a self-sustaining colony. There has to be stronger incentives for people/companies to move there. Even on earth there are many economic zones incentivized by lack of regulation etc.
The economy is just not going to work.
The parent comment isnt saying there will be an economy of building things on Mars and sending them to Earth, they're saying Mars can sustain itself without sharing an economy with Earth. Which I believe is true.
And for what it's worth, I'm actively working to build better robots with commodity 3D printers[1] and I hope to build self sustaining communities on Earth with 3D printed micro factories that produce all the goods humans need for survival.
I believe it is possible to make economically closed self sustaining communities. Both on Mars and on Earth. We've done it on Earth for a long time.
Self-sustaining community that can economically fund itself is out of reach even here on Earth. And, frankly, 3D printing isn't magic: it won't help that much. Can you 3D-print a glass window that can withstand 1 atm and has anti-UV coating?
I'm talking 10-20 years out for having a self sustaining community that manufactures its own hard goods. But I believe it is possible and I'm working on making it real.
I'm not relying on magic.
My (very uninformed) guess is that you could probably build a self-sustaining community using 3D printing, on the Alps or the Appalachian. (After all, our ancestors managed with stone tools.) Doing that on the South Pole will be challenging. Mars, forget it.
If you are persistent enough you could probably 3D print everything, I guess. Maybe you could 3D-print concrete and ceramic blocks to build a furnace that will be used to produce steel which will be shaped into a pipe (by another 3D printed machine) to transport hot gas to melt silicon oxide and produce glass.
However, after a few iterations, I guess people will ask "Why don't we just pour concrete over here in conventional way? That's much easier and cheaper."
I do think, however, that robotics and additive manufacturing will be critical to building significant parts of the machinery and buildings on Mars.
Certainly, sometimes you will use traditional manufacturing methods to construct things. But additive manufacturing has different capabilities and it will be used for different things. And unlike some people who claim additive manufacturing can't be used for anything, I believe that a mixture of traditional manufacturing methods and additive methods will be critical to building a colony on Mars.
Imagine for instance that you want to build some buildings. Lets say both pouring concrete and additive manufacturing methods would work. You need to build 40 habitats. Would you rather work all day in a space suit in the hazardous near vacuum of Mars to build the forms needed to pour concrete for the structures? Or sit in your pajamas in a habitat on a computer designing and controlling the robots that will do it for you? And in that case, maybe you will want to have the robots make forms and pour the concrete for you, but perhaps you will use additive manufacturing methods.
I can imagine the latter is easier for robots, and using robots is easier for humans than doing the labor themselves.
Of course, to build a robot that will manufacture a home out of concrete, you need to build the mechanical parts of that robot. How will you do that? Probably not with CNC machines and blocks of aluminum (making such parts was my job for 7 years BTW). Instead I imagine that you will keep a library of feedstocks for 3D printing and you will print out the robot parts in your lab.
Interesting fact: there are now some extremely high performance plastics available for common home-style 3D printers, including carbon fiber filled PEEK. At $850 per kg that's a material I don't think you'd use unless you had to, but if I were building a colony on Mars at $500k a head I think I'd bring 100kg of that stuff.
100kg of carbon fiber filled PEEK plastic will make a lot of concrete extruding habitat constructing robot frames.
You'll have to bring the motors and electronics separately. At least until you build that foundry....
See what I mean when I say 3D printing can help make a self sustaining economy possible?
The goal of Mars colonization is to create a second (eventually) independent base, so humanity has a chance in case of a catastrophic event.
I'd say even if it costs a trillion dollars, it's worth it. US GDP is what, 18 trillion per year?
If humanity is wiped out on Earth, people in Mars are fucked anyway: they will be one depressurization accident from extinction.
How could they even begin to try to rebuild civilization when they can't even go outside without an apparatus that took thousands of years of science to produce? What is the speed divisor for advancement of a society marooned on a world it didn't evolve to live on?
I'm all for Mars colonization, but as a backup plan for Homo sapiens, it kind of sucks.
It is when a private company is doing it.
That said, I am also doubtful. I don't foresee a trade-hub attracting 1 million people - if there are really a million people who want to go. Who the hell wants to risk their life and net worth just for the privilege of living on a rock less hospitable than Antarctica?
Launches, yes, but landings? Athmosphere is your enemy during launches, but your friend in landing.
Mars has an atmospheric pressure less than one percent of that of earth. That makes losing speed other than with rockets a problem, and that requires bringing lots of fuel.
In addition, the athmosphere that's there can be windy and turbulent. That can directly affect a spacecraft, but also causes dust storms that can make it hard to measure distance to ground.
In other words, I believe that Mars' appeal is a mirage. Musk and company are seeing it as another Earth where people can live like here, with a little terraforming.
I think it would be much more difficult. Of course I could be wrong, or I could be right but, even then, Musk could be modern Columbus.
- Water and free carbon dioxide are hugely more abundant on Mars than on the Moon. These are essential supplies for increasing biomass and making fuel.
- There's a nice, somewhat-protective atmosphere.
- There's a 24.66 hour day.
- Temperatures are relatively moderate.
[1] - http://www.nbcnews.com/id/6908408/ns/technology_and_science-...
If you can get net energy by fusing He3, you can also do it by fusing deuterium, which is easier. And the end product of deuterium fusion is He3! (Half the time directly, the other half producing tritium which decays to He3.) So instead of sifting through millions of tons of dirt on the moon, you can just make He3 on Earth and gain energy in the process.
Deuterium fusion produces neutrons but they're lower energy than D-T neutrons. Fusion startup Helion (funded in part by YCombinator) is working on a hybrid D-D/D-He3 fusion reactor, and says only 6% of the output energy would be as neutron radiation.
That's pretty much the whole of the economics. People and governments will jump at the chance to send humans to Mars, if there's a way to do it at a reasonable price.
The cost of the things that are necessary on Mars that will have to be shipped from Earth will be rolled into the ticket price. Hence the first few rounds of tickets will probably be quite expensive.
How exactly do you know that? The only experiment about creating closed human colonies was deemed complete failures and not to be replicated due to ethical concerns.
And a base on Mars will not be a closed system. It will continuously draw in raw materials from the surrounding environment. Mars is enticing for this because carbon dioxide and water are abundant, giving you the three most important elements for fuel and food production.
We've never done this on any significant scale with success.
Think of it more like a nuclear submarine with a greenhouse full of potatoes attached -- we can most likely do that.
Nobody's going to try to launch an entire mangrove forest on the first go. Biosphere2 is a failure of experimental design, not a failed experiment.
Maybe, but if we want to make Mars economically self sustaining the correct analogy is nuclear submarine that never surfaces and can totally self repair, including building new nuclear reactors and eventually replace all parts in itself.
There was Biosphere 2 experiment few decades ago, but they could not keep the biosphere stable.
There's just a huge psychological difference between knowing that you're in space, millions of miles from Earth or any kind of help and knowing you're in a simulation on Earth.
I suppose it's possible to fool people that they're in the former while actually being in the latter. But the ethical issues surrounding such an experiment would make it out of bounds for NASA. It might make for a fun scifi story, though.
To make the colony self supporting, you need to transfer factories, chemical plants, machine industry, mining industry, etc.
The really cool thing about this is that methane can be used as a feedstock to produce many plastics and the oxygen can be used for humans to breathe.
The MCT is a prototype for a seed factory style Von Neumann probe.
Everyone's keeping quiet about the inevitable role of RTGs or fission reactors in early human Mars exploration.
Solar will come either via an abundance of payloads delivered to Mars as things ramp up, or via panels produced on Mars itself.
Other viable methods for power generation that are amenable to in-situ production include geothermal heat loops and solar concentrators.
Like they said, most of the cost is transportation. Which gets cheaper.
If the real extraction happens on asteroids, then Mars or even the moon are a better base of operations just due to the smaller gravity well. And Mars isn't without its own mineral wealth. Several that would be important for growing food.
If you look at the delta-v map of solar system, everything massive like planets, is not going to be hub or center of extraction of minerals for other places. Mars would sit at the bottom of gravity well and be economical sink.
Deep space mining (robotic or semi automatic) of asteroids can be economically viable, but just few relatively small asteroids would provide Earth or Mars for centuries.
But raw materials are not enough, you would need industry to build all stuff you need and maintain it. If you can't manufacture 3D printer or CNC milling machine by yourself, you need to buy it from Earth. Just being able to make cast iron is not enough, you need high-tech equipment and manufacturing for them to survive.
Making Mars self sustaining circular economy would be massive systems engineering challenge.
Isn't that what that documentary Biodome was all about?
Adjusted for inflation, US gov't spent the equivalent of $65 billion/yr in the 1960's to get a man to the moon:
Obviously, that'd be backup to backup plan for funding.
I'd guess that if the objectives and constraints used in the design process were revealed, it would all make complete sense. Elon has a track record of making technical and business decisions that turn out to be 100% correct in retrospect. The epic size of the vehicles are a feature, not a bug, for instance.
Musk has been surprisingly silent (or has seriously downplayed) on the radiation question, which is a pretty big deal for travel beyond earth's magnetosphere.
But here's the thing, IMO: Musk is offering ITS as a transport facility, nothing more, nothing less. If you have payload (a living human) that is fragile (sensitive to radiation) you bring your own extra styrofoam (you include weight of shielding water or lead or what have you as part of the payload).
But if he says that out loud, it'll hurt the momentum of the movement.
So there you have it.
I don't know that they'll have this on the first trips there, but I'd guess that magnetic shields might eventually be a standard component:
http://space.stackexchange.com/questions/3772/how-much-power...
But since for most of those people, SF and anticipation is limited to Star-Wars + a couple of other movies/series and super-hero block-busters, they are not aware, and all these stuff appear as genuinely unprecedented technical and sociological thought breakthrough.
The challenge with flares is that the radiation can come in from multiple directions, so a cylindrical water container that people can pack into is probably a better defense than just the bulk of the engines.
If it's a major problem, they might just orient the ship in a direction that gives the best radiation protection to the passengers and just leave it like that for most of the trip.
Early trips would of course not have a large crew, since they'd be mostly focused on setting up a base, and be more about cargo and equipment. Saying "several tens of millions" is because that's generally what it costs right now to get someone to low Earth orbit. If we can get early trips to Mars down to what it would cost for a current orbital mission, that would be very impressive.
Start with ~$30 million (based on "several tens of millions") to get a person to orbit using current tech. Current tech doesn't use reusable rockets, and the cost of building a rocket greatly exceeds the cost of the fuel for the launch, so we'll assume fuel costs are 0. If you make a rocket that you can reuse for 10 launches, your price tag is down to $3 million to get a person to orbit. The next step is to make a bigger rocket: currently the Soyuz rocket is the only rocket taking people to the ISS (assuming this is roughly what you mean by getting someone to low Earth orbit), and it can only take 3 people at a time[0]. If you make your reusable rocket big enough to take 100 people at a time, your price tag goes down ~33x to $100k to get a person to orbit. Of course, a bigger rocket will probably cost more to make than current "small" rockets -- but a big reusable rocket would have to cost 330x more to build than a modern small rocket for future seats to cost ~$30 million per ticket.
So even the first trip to Mars should be well under $1 million per person as long as they make the rockets big and reusable.
[0] http://www.nasa.gov/audience/forstudents/k-4/stories/nasa-kn...
Even if the cost for the first few trips was $50 million per person, there'd be no shortage at all of people who would be paid for by governments or organizations with that kind of money. Might as well use it, and apply these funds to expanding the program.
Full reusability is really the essential part of this system - you can't afford to throw away any stage of a rocket this big. Fortunately, the larger the vehicle, the easier reusability tends to be (up to a point of course).
The implication is that you'll probably want to design an entirely new rocket if you want to make one that's significantly bigger than what you've made in the past, because rocket designs aren't going to be fully reusable at significantly different scales.
That's where the economic perspective comes in: rockets are expensive, and the bigger they are, the more expensive they'll be, from a raw materials perspective at a bare minimum. The hundred person rocket that Musk has proposed would already be significantly larger than any actually constructed rocket to date, so it has to be a new design, which means they're going to have to build and test prototypes. And some of the prototypes will probably blow up during testing -- hopefully not many, or they'll run out of money and won't be able to keep going.
Now if you want to build a rocket that can hold a million people, you'd probably be talking about the largest man-made structure ever. The only structure on this scale that I'm aware of (which was never built) is the X-Seed 4000, which would have housed 500,000 to 1,000,000.[1] Its proposed height was 4000 meters, which is about 33 times taller than the proposed SpaceX interplanetary rocket. If you scaled up the SpaceX rocket design to that height, the mass would increase 36000x, and the breaking strength would only increase 1000x. I think we would probably need some major advances in materials science to be able to make a rocket that big that didn't just disintegrate on launch.
Secondly, what about the economics of a million person rocket? The X-Seed 4000 would have cost roughly a trillion dollars (in 2016 USD) to construct, and it just has to sit on the ground. I'm going to assume that at the barest, most insane minimum, it would cost at least 10x as much to build a rocket that size. So that's 1/7 to 1/10 of global GDP (in 2014)[2] -- for one rocket -- that will probably disintegrate.
But! Let's assume that we make major materials science advances and can actually make it work, and we make it reusable up to 10 launches, and somehow we get the whole planet to agree to build this thing. The price tag actually isn't so great... $10 trillion / 10 million people = a million dollar price tag per ticket. So maybe my estimate is too high and we could build a rocket that big for a trillion, no more than building a building that big. Even then you're still looking at $100k per ticket.
So, in short... My guess is that there might be some technological and economic sweet spots that are a bit bigger than than the SpaceX design, but I think it's a good starting place in terms of feasibility. And yes, in practice there are some limits to how big you'll make your rocket.
PS. I don't think "breaking strength" is likely the most relevant factor for rockets (I an not a rocket scientist), but it's the principle of the scaling thing that matters. Plus a rocket has to have supporting structures to help it keep its shape, so breaking strength might be relevant after all.
[0]https://www.av8n.com/physics/scaling.htm#sec-strength (I linked to the section on how breaking strength varies with scale because it seemed the most relevant to rocketry, but the whole page is useful for explaining many of the ways in which things vary nonlinearly with scale).
People already stay on the ISS two to four times as long as Musk's proposed travel time to Mars, and they'll be landing somewhere with a third of Earth's gravity. They might all need to hang out for a day or two to get their Mars legs, but I don't see an issue here either.
Micrometeorite impacts haven't done the ISS any appreciable damage in its nearly 20 year service history. Again, doesn't seem like a problem.
People can definitely survive living almost entirely indoors. I expect VR will be big on Mars. But I think the lack of natural light will really limit the comfort level.
If someone can invent an invisible electromagnetic radiation shield that would change the game.
If we can find some nice lava tubes that can be sealed and pressurized, it might make for some rather spacious dwellings. But yes, I expect the first Martians to effectively be mole people.
I imagine living on Mars would be a lot like living in a place like Whittier Alaska [1] (a town where everyone lives in the same building). Not for everyone, but some people might like it.
[1] http://www.npr.org/2015/01/18/378162264/welcome-to-whittier-...
http://www.sr2s.eu/project-news/19-eu-space-project-will-all...
A penny-sized hole would give time to patch, and suits would likely be designed to compartmentalize in a leak. In a true worst-case scenario, chimp studies in the 1970s showed they could survive several minutes of total vacuum.
https://www.scientificamerican.com/article/survival-in-space...
These year long stays were on the space station, which has similar or less shielding. The Earth's magnetic field helps, but really, by the time you get to your Mars habitat with unlimited shielding mass available, your total dose is not that high.
http://www.theverge.com/2016/3/1/11138102/scott-kelly-year-i...
I guess they aren't well characterized yet.
Early travelers will face very significant risks. Radiation and zero g are indeed risks, but a minor compared to the other risks.
If you have a 5% of dying in transit or at Mars due to equipment failure, as well as a 2% increased chance of getting cancer at some time in the future, the first obviously is the one to worry about.
Have there ever been any serious plans or proposals to do that?
You really want a pretty large diameter so that you don't have a huge gravity gradient causing your astronauts discomfort. Tethers might be more practical than the classical doughnut designs for the near future.
I'm thinking (no spoilers) specifically of how Ceres, having been spun up to provide artificial gravity, becomes a destination for expecting mothers trying to avoid complications associated with low-G.
http://www.bloomberg.com/news/articles/2016-10-17/why-elon-m...
It's unlikely to be a worthwhile export though. One in 2500 hydrogen atoms in Earth's oceans is deuterium. There's enough in your morning shower to provide all your energy needs for a year, and enough overall to run civilization until the sun goes out.
Isolating the deuterium takes some effort, but it's not terrible, and certainly easier than transporting it from Mars, even if isolating it on Mars were free.
Mining might be lucrative if Mars has gold or platinum or some valuable mineral that's easy to extract and worth more than its shipping cost back to Earth.
I'm skeptical that patents are going to be a major export. Inhabitants of Mars presumably will have better uses of their time than filing patents, and they would be competing against Earth-bound innovators against whom they don't have any particular advantage other than necessity. (Ideally, Mars wouldn't itself even be subject to patent law.)
Space Tourism will be a thing unless there's some explicit policy to prevent wealthy thrill-seekers from going to Mars if they don't plan on doing any actual work while they're there.
Science and exploration might be valuable professions. Like, if people on Earth put bids on locations, saying "I'll give you a thousand dollars if you drive your rover out to this location and take a few pictures and pick up some rock samples". Mining companies might be especially interested, but so would Earth-bound scientists who just want to know more about Mars.
Real-estate speculation might be another cottage industry. Developers are going to want to establish homesteads in valuable locations, and then they can sell adjacent lots to newcomers. (This assumes some kind of sane framework for land ownership. Hopefully such a thing will strike a sensible balance between being able to claim "dibs" on entire landscapes vs not having property rights at all.) As long as the population of Mars is growing, this could be a lucrative profession.
Musk has said there will be no screening of the Mars colonists, and that anyone could go. That means someone who's mentally unstable and/or wants to make a name for himself (ala Herostratus[1] or any number of modern publicity-seeking terrorists and murderers) could go and attempt to harm the spacecraft or colony, both of which would be incredibly vulnerable to such intentional attempts at destruction and are guaranteed to get massive publicity were they to be destroyed or even merely attacked.
This could become even more likely if living on Mars long-term actually becomes viable, and people wind up spending decades on there. Some people will likely go stir-crazy and attempt to harm themselves and/or others.
People who are allowed to go live in Antarctica or out in to space are currently screened very carefully to be compatible with each other and able to psychologically withstand the rigors of life there, and the relative isolation. But there will be no such screening for the Mars colonists, according to Musk, and the isolation and danger on Mars will be even worse than it is in Antarctica.
The isolation and danger will be hugely stressful and difficult to deal with over the decades people will live on Mars. I've read that even in Antarctica, people are rotated out within a year or so because of the psychological difficulties of living there, and no one's been in space for much more than a year.
Every ship produced is a new member of the fleet that continually moves between both planets. Opening up an interplanetary transportation corridor. If you're someone with the spirit of a colonist, an explorer, an adventure seeker (there are many in the world with that attitude) then Mars is going to be the place you want to prove yourself on. It is romantic, risky, badass, and there are no shortage of people who are going to take the challenge.
An ever increasing number of ships leave every 2 years, and you always have the option to come back. I can easily see people doing fundraisers to go, universities offering scholarships, governments setting up stations to claim some land, companies sponsoring infrastructure projects to say they have a presence on Mars, etc..
Correction: some of the smartest engineers in the US, maybe. But US laws don't allow SpaceX to hire anyone from outside the US.
This of course isn't to imply that SpaceX has a monopoly on talented engineers, I'm sure they exist all over the world.