Planets Are Dumb

I really don’t understand why people want so badly to colonize Mars.

Okay, that’s a lie, I totally do – because it’s cool. But that’s actually a kinda terrible idea. In space… everything is super expensive. At least at the start, but considering that it costs on the order of millions of dollars to launch a satellite – not build, but launch – I’m going to say that’s a fairly accurate summary, for now.

Colonizing planets, though, that’s more expensive than usual. And for one simple reason:1 gravity wells.

The trick to putting something in space is beating a gravity well. Once you’ve got something in space, you mostly just need to refuel it every once in a while, and other than that, assuming you’ve built it well, it can be a self-sustaining system.2 So, fuel, that’s something that has to come from a planet, right?

Well… no. Modern space propulsion systems (ion drive, plasma rocket) run off of stuff that you can easily get in space. Rockets don’t run on fossil fuels, except at a couple of steps of remove.3 They run on stuff that’s easy to manufacture from raw materials, as long as you’ve got energy. You’re in space, so you’ve got either solar cells or a nuclear power plant, so we can go ahead and fiat energy requirements. Now, raw materials: asteroid mining, anyone?

That’s basically the trick, and why planets are dumb. Yeah, they’re a big source of materials, but mining for materials takes more effort as you get deeper. Plus, you’ve escaped one gravity well just to get caught in another, and a gravity well is the single hardest thing about space travel.4 Once you’re in space, just mine asteroids for anything else you need. Including living space – raw materials can be converted into anything you want, at that technology level, with just energy input, and we’ve fortunately got a lovely mass of burning hydrogen throwing plenty of energy at us, so that shouldn’t be too hard for another few million years or so.

So: stop saying we should colonize Mars. That’s a stupid idea, and the sort of vanity project we can leave until we’ve at least fired a colonization project towards another star system. No, first priority should be some permanent habitats out in space. The ISS is nice and all, but I’d love to see, say, a Stanford Torus out there. There’s a reason Interstellar didn’t have people colonizing Mars.


  1. Cue BuzzFeed offering me a writing position 
  2. This is assuming you got to space responsibly and didn’t just bum-rush for the Science Victory while ignoring stuff like, I dunno, ceramics or whatever. Oh, Civilization jokes, I’ll never get tired of you. 
  3. Step zero: rocket fuel. Step one: rocket fuel being manufactured, using electricity. Step two: Electricity being made by burning fossil fuels. 
  4. Well, that or the fact that you’re roughly a gojillion miles from anything else. (And yes, I did pick ‘gojillion’ because I’m pretty sure it isn’t a real number. That was the point.)