Lots of people are excited about Elon Musk’s plan to colonize Mars. It ain’t gonna happen. Here’s why.
Economics
Look around you. Consider all the stuff you have: where did it come from? Well, some of the clothes you’re wearing might have been made in China; about 30% of all the world’s clothing is made in China. You might be wearing something made in Bangladesh; they supply about 20% of all the world’s clothing.
What about the computer you’re using right now? Its components come from all over the world: China, Malaysia, Taiwan, South Korea, and a host of other places.
It gets really crazy when we talk about the sources of various special materials. Rare earths, for example, come mostly from China, but some of these vital industrial elements come from Myanmar, Australia, Thailand, India, and Russia. Mozambique exports large amounts of aluminum and titanium ore. Namibia is the biggest exporter of uranium. Russia, Brazil, and South Africa provide most of the world’s vanadium.
Odds are high that you have in your home products that came, in one form or another, from almost every country in the world.
Think about this in terms of the people with whom you interact with economically. For example, let’s talk about that half-gallon of milk you just purchased at the supermarket. That required you to interact with just one person: the checker whom you paid, right?
Well, that’s true, but that was only the first level of economic interaction. You wouldn’t have been able to purchase that milk if somebody hadn’t put it on the shelf in the supermarket. For that matter, you were also, indirectly, interacting with the truck driver who brought the milk to the supermarket and the manager who keeps the supermarket running smoothly. Further back in the supply chain are the people who work at the dairy where the milk was packaged and the farmer who tends the cattle who make the milk. But let’s not forget the fact that the trucker needs a truck and fuel; think about all the people required to manufacture and fuel that truck. Think about all the different materials required for its manufacture and where those materials came from. The supply chain for that truck involves millions of people.
But it doesn’t stop there. Those millions of people who directly contributed to the manufacture of the truck have their own requirements. They need food, water, housing, sewage processing, and all manner of support services. That brings in millions and millions of other people, and when you take the needs of THOSE people into account… well, you end up with the entire population of the planet. If you trace the supply chains for every product or service you obtain, and trace the supply chains for those workers, you’ll end up with the conclusion that, one way or another, you are economically interacting with almost every other person on the planet. That interaction might be many times removed from you, but it’s real.
Hence, it takes 8 billion people to support your lifestyle, as well as a stupendous amount of land and equipment. We’re not going to be able to ship all that to Mars. We’re not even going to be able to ship a small portion of that stuff. Even with hundreds of Starships, trillions of dollars, and decades of effort, we won’t be able to get anything more than a microscopic fraction of the stuff needed to sustain a civilized life.
The absolute minimum
So, what is the absolute minimum size of a colony on Mars capable of sustaining itself, assuming regular shipments of supplies from earth? The core problem is the long delay between identifying an unanticipated need and the arrival of the necessary resource. Suppose, for example, that a colonist breaks their leg so badly that intramedullary nailing (a metal rod running up the femur) is required. Such rods must be tailored to the individual and require special construction; they would not be included in the normal inventory of medical supplies and could not be manufactured on Mars without highly specialized equipment. The travel time from earth to Mars depends heavily on the alignment of the two planets. If they line up perfectly, it can be done in a few months. Under bad conditions, it could take two years. Of course, there will be a steady stream of cargo arriving during the good months, but this could not cope with the broken leg problem. In such a case, the doctors would have to use a temporary fix and ship the unfortunate colonist back home for proper medical treatment and rehabilitation treatment.
A more serious problem would be posed by a failure of a part of the energy system. The colony would require large amounts of energy for heat, light, and to power the various recycling processes required by the colony. In particular, it would need high redundancy — three independent sources of energy would be necessary. The best option here is a triad of small modular reactors. With such a system, the colony would be able to cope with the failure of two of the three reactors in a low-energy emergency mode. Still, such a system would comprise at least a thousand tons of cargo, requiring ten deliveries and the installation of all three systems before actual colonization could begin.
The requirements of redundancy impose huge costs on any such colony. They would need a backup version of every system required for the colony to function. That would include communications systems, lighting systems, heating systems, water management, sewage management, food production, CO2 scrubbing, oxygen manufacture, and basic medical functions. Moreover, they would need specialists capable of maintaining every critical system; that would add up to a lot of people, requiring even more food, water, oxygen, etc.
What would they do?
Here’s one of those dumb questions that are seldom asked: what would the colonists do? Let’s put aside the support staff; doctors, engineers, technicians, managers, etc. What’s the point of setting up a colony on Mars? This, it turns out, is the killer problem. There’s nothing that can be done on Mars that can’t be done a lot more cheaply on earth. Some people suggest that we could mine valuable minerals on Mars and ship them back to earth. But all mining requires some sort of processing, and processing ore requires gigantic installations gobbling up huge amounts of energy. The cost of transporting, building, and operating such installations would far exceed the value of any materials returned to earth — and that doesn’t even take into account the cost of shipping stuff back to earth.
So what could colonists do that would pay the costs of the colony? Design video games? Nope: it’s cheaper to do it on earth. Operate an astronomical observatory? Nope; it’s cheaper to loft one into orbit. There just isn’t any economically productive activity that can justify the cost of colonization. That, ultimately, is the killer arguent against colonization of Mars. It’s just too damn expensive.
If we need more lebensraum (German for “living space”), we could start colonizing Antarctica. It’s a much nicer and safer environment than Mars. It’s warmer, there’s enough oxygen to breathe, there are penguins to look at, and mining there might even be economically viable. There’s enough space there for a billion people. Or we could put colonies at the bottom of the ocean — that would be less technologically challenging, easier, and cheaper than Mars.
As for Mr. Musk’s notion that we need a second habitat in case the inhabitants of earth destroy the place… that’s nonsense. If earth stopped sending supplies to Mars, that colony would die out in a few years.
If Mr. Musk wants to blow his wealth for a colony on Mars, that’s his business. His $350 billion, however, won’t pay the costs of setting up even a small colony on Mars.