The Future of Space Travel

Think of this as the Sandor at the Zoo equivalent of a year-end wrap-up post.

Some scientists are petitioning Congress to resume manned lunar travel.  This is dumb.

It’s dumb for a lot of reasons, but the main ones are:

  1. Manned rather than unmanned space exploration is ludicrously less efficient.
  2. There’s nothing to do on the Moon.

Let’s come back to humans versus robots.

The Moon is maybe the least interesting stellar object around.  It’s totally dead.  It has no particularly useful resources (no, He3 mining is not serious, guys).  There’s just no reason to go to it.  Anything you could do on the Moon, you could do in Earth orbit instead, and you could do it better, and without the technological hassle of landing in a gravity well (albeit a weak one).

The same is not true of space.  Wikipedia notes:

In 1997 it was speculated that a relatively small metallic asteroid with a diameter of 1.6 km (0.99 mi) contains more than $20 trillion USD worth of industrial and precious metals.[6][35] A comparatively small M-type asteroid with a mean diameter of 1 kilometer (0.62 mi) could contain more than two billion metric tons of ironnickel ore,[36] or two to three times the annual production of 2004.[37] The asteroid 16 Psyche is believed to contain 1.7×1019 kg of nickel–iron, which could supply the world production requirement for several million years. A small portion of the extracted material would also be precious metals.

But of course the cost of extracting such ores and repatriating them to Earth makes asteroids currently valueless.

There is also energy in space.  Solar power in space is not subject to inconvenient night or weather, nor does it black out hundreds of square miles of habitat.  It could in principle be beamed back to Earth with masers, which — though it kills the efficiency of the operation — is at least more realistic than sending ore back down to Earth.

Right now, the economic value of space is limited to the economic value of satellites and their ability to take pictures and relay data streams.  If space is going to ever be more than a vanity project of countries looking to establish a reputation for national greatness, that will have to change.  Even if we discover microbes on Mars or Europa or something, even if we send a manned mission there, that will no more set up an enduring human presence on those destinations than the Moon missions did in the 20th Century.  Man will inhabit space only to the extent that there is some value there.

So if what you want is to expand to fill the solar system, it’s all about figuring out some economic reason for the move.  You don’t want manned lunar (or Martian) missions for that.  You want two things:

  1. Dramatically lower the cost of getting to and from space.
  2. Figure out something that you can exploit for relatively high returns.

Thing #1 is happening right now for rocketry — SpaceX for example is doing dramatically cheaper launches than the previous state of the art — but probably rocketry will never be all that efficient.  To really open up space, you need some kind of not-entirely-rocketry based approach to launching from our gravity well.  A beanstalk is probably fantasy.  Skyhooks or launch loops are still unlikely, but not as completely ludicrous.  Just a launch railgun could help.

Thing #2 is probably ore or power, and how profitable it needs to be depends a lot on how much of a cost savings you can get out of thing #1.  But these are both Big Items.  Orders of magnitude need to be achieved in launch cost savings, and major technological research would need to be engaged in to make even realistically lower orbital costs worth it in power or ore generation.

But if that happens — if there are resources that reasonable people might seek in space — then we’ll come back to manned versus unmanned missions.  And I think it’s likely that ultimately the result will be manned space stations (at least).  Right now, unmanned robots are great for exploring Mars and such — because the relative clumsiness of such robots is kind of irrelevant compared to the huge benefits of getting them where they need to go.  When there’s no real benefit besides some mild scientific gains plus national greatness returns, what you’re trying to do is lower cost as much as possible.  And robots will always beat humans, cost for cost.

If, on the other hand, you’re potentially getting some real economic returns from space, then the question becomes not lowering costs, but balancing cost/benefits.  And the truth is that right now, robots are ultra-clumsy and not suited for handling complex jobs.  And that’s without multi-second or longer light-speed lags between their controllers and the robots.  If, on the other hand, there’s a reasonable chance for a billion dollar investment in an asteroid mining facility to have a hundred-billion dollar return, but only if you can actually operate the damn thing, you’ll put a small group of human overseers up there to trouble-shoot it.

This assumes that artificial intelligence doesn’t advance enough to render human oversight kind of pointless.  If such an advance does happen, well, I think the consequences on Earth will be hard enough to predict, much less farther out.

So if you desire to see humanity spread across the Solar System, then try to get NASA interested in economic launch technologies and asteroid mining/orbital solar power.  Not useless trips to the Moon.

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