Now that Neil Armstrong is no longer with us, one third of all the human beings who ever walked on the Moon are dead.
Nobody, not even J. G. Ballard called this one -- that after our biggest success in what was then called the Space Race, with a world that has since grown continually more wealthy and technologically advanced, we would simply stop sending human beings to other worlds.
This is the point at which, as a science fiction writer, I'm supposed to launch into a jeremiad about the failure of nerve of our culture and science fiction's enabling role in not providing sufficiently moving myths to overcome that failure of nerve.
But it is always better to understand than to complain. So let's consider why we haven't sent another man (or the first woman) beyond low Earth orbit in the last forty years.
The big culprit here is Earth's gravity well. It takes an enormous amount of energy to break free of it and that energy is tremendously expensive. The first modern science fiction writers imagined that space travel, once achieved, would become progressively more efficient and less expensive, the same way that land travel, sea travel, and air travel had. It was a good model and up through Apollo 17, everything looked to be right on track.
But (damn physics!) manned space exploration remains extraordinarily expensive and looks like it will be so for the foreseeable future.
The lesser culprit is the lack of a goal compelling enough to make a nation sink that kind of money into manned space exploration. China has plans for a manned Moon landing . . . but they're doing it for the same reasons the United States did in the late Sixties and early Seventies. To prove that they're a major world power capable of extraordinarily difficult and expensive feats.
The U.S. has already proved that with Apollo 11. That's an accomplishment which, like Yuri Gagarin's first flight into space, cannot be taken away from a nation. In order to keep going, after the prestige has been gained, there must be other reasons.
In the old science fiction model, space flight would become increasingly cheap, more and more people would be able to afford it, and they'd take off for parts unknown for a variety of reasons, both self-serving and idealistic. To mine the asteroids, the build Lunar colonies, the terraform Mars, to escape an overcrowded Earth. None of which looks likely to happen anytime soon.
So at the present time the arguments for manned space exploration are:
1. Scientific curiosity.
2. The prestige of doing so.
3. "Because it's there."
Which apparently aren't enough.
Manned orbital missions, you'll note, are doing just fine. That's because there are a lot of military and economic reasons for having an orbital presence. We'll have manned missions to other planets as soon as we can come up with a strong reason for them. One that's strong enough to convince, let's say, Mitt Romney and Barack Obama that serious money should be committed to it.
I don't have that reason. But some years ago John Barnes explained how we could find one. Send out thousands of small, cheap probes, he said, to every part of the Solar System. Let them gather information. Build a data base of that information. And when that data base is large enough, it will tell us why we should send human beings out into space.
To which I can only say, Amen.