Monday, January 28, 2008

Missing the Moon

There have been a couple of fascinating articles recently on the Vision for Space Exploration that President Bush has inaugurated, which details plans to return to the Moon and set up a permanent human presence there, and then going to other places in the solar system. The first article is from Aviation Week and the second from Popular Mechanics. The main point of contention is whether we should bother returning to the Moon before going on to Mars and near-Earth asteroids.

There are some good arguments for bypassing the Moon. One is that, once we've escaped from the Earth's surface gravity, it really isn't that much more difficult to go to Mars than the Moon. As Robert Heinlein (I think) said, "once you've achieved low-Earth orbit, you're halfway to anywhere in the solar system". Moreover, there are considerable benefits to going to Mars first. This is the motivation behind the Mars Direct project that has been championed by the Mars Society.

Another reason is that other locations would have more scientific value than merely returning to the Moon. One possibility is to set up a space station at the L1 Lagrange Point, where the gravity from the Sun and the Earth cancel each other out. This would be very fruitful scientifically, and it would represent a greater achievement than returning to the Moon, since it's a greater distance. Another possibility is near-Earth asteroids, that haven't been as "polluted" by the Earth as the Moon has. Moreover, many such asteroids have orbits that take them from Earth's orbit to Mars's, Venus's, even Jupiter's. It might be a good way to hitch a ride.

A third reason is more basic: we've already been to the Moon. Obviously, we haven't spent that much time there, but if we have the resources, maybe it would be better to explore a more foreign terrain.

The articles don't mention any downside to not going back to the Moon before Mars. I don't really have a problem with going to Mars first, but I think it will eventually be important to set up stations on the Moon. My grounds for this are psychological: Mars is a dot in the sky, near-Earth asteroids can only be seen with telescopes, and the L1 Lagrange point isn't a body at all, just a moving location in space. The Moon is, comparatively, a very large object in the sky that we see almost daily. To have people at these other places will be very valuable, but I suspect it won't capture people's imaginations the same way as going to the Moon would. For centuries, more literature has been written about the Moon than about Mars and the other planets.

Part of the reason for this is that civilian tourism to the Moon would be much easier, simply because it's close and wouldn't take as long to go there and return. If people think of the Moon as a place to which they can go themselves, they'll be much more excited than they would be by a space program that is only focused on places so distant that tourism would be impossible (at least with current technology).

Plus, if one country goes for Mars, while another goes to the Moon, it will give the superficial impression that the second country's space program is superior to the first country's, since its achievements will be more conspicuous. I don't want to be too nationalistic here -- in fact, I might prefer it if these projects were done by civilians and businesses rather than governments -- but as long as any kind of space race is going on, I'd like my country to be ahead. Of course, I'm thinking of China's space program, which hopes to send people to the Moon by about 2020. Having said all this, I'd still probably be ecstatic if they did it.

As I say, I don't have a problem with going to Mars first, as long as we get back to the Moon eventually. The Moon Society does not necessarily advocate returning to the Moon before going anywhere else, but they do advocate for a human presence on the Moon. I tend to agree.

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