To round off Jose's debate with Charlie about whether or not we should be pursuing manned or unmanned expeditions in space I wanted to consider the incentives driving the push outward. During the first period of space exploration the incentive was that of national pride, of competition between the two sides during the cold war to get the first satellite in orbit, the first man in space, the first to walk on the moon. Science at this stage, the search for knowledge, was a marginal incentive at best. After the Apollo program became prohibitively expensive (and boring for the viewers at home) science began to provide the primary incentive; our desire for discovery and exploration, to find out what is up there, (and also to spy on what is down here) started to drive the space program, but it was always and will always be at the mercy of those who control the purse strings. The third set of incentives, which started with the first commercial telecommunications satellites and has continued with G.P.S.(Yes I know it was a military project at first, but it is one of the few that has repaid its initial investment) etc., was the commercial incentive; the desire to make money out of space, and it is this I would argue, which will drive the next phase in the space programme, the exploitation, rather than exploration, of space.
On the blog Joe Haldeman mentions that it is only when "cislunar space offers goods and services that can't be had more cheaply on Earth," that we will see the next phase in technological development, such as space elevators or their equivalents, thus allowing us to lift large masses cheaply and truly begin the manned exploration of the solar system. Well what type of goods and services can we expect space to offer us? On the services side the nascent space tourism industry provides an incentive for research into manned space flight. There are an awful lot of jaded billionaires and multi millionaires out there who will gladly pay for the chance to see the curvature of the earth and while this will undoubtedly be a minority pursuit for quite some time, the need to make money out of such ventures will help guard against the traditional bureaucratic excesses and wastages of which NASA is famously guilty. While scientists may shudder at the thought of the ISS being used as a glorified hotel for the hyper rich, if we are honest is it currently being used for anything more worthwhile?
The question of goods however is a tricky one. There has been much speculation over the years about whether or not zero G manufacturies might be able to produce goods that are simply impossible to make on earth, such as novel drugs or crystals whose molecular structure requires a freefall environment. While this is perfectly possible, the thought that these could be produced in large enough quantities to justify the time and expense of setting up such manufacturies and providing them with raw materials from earth is rather dubious at the moment. So what are we left with? The debate about where to go next has tended to focus on the nearest planets, the Moon and Mars, and while the moon's gravitational well doesn't pose too much of a problem to a returning expedition, Mars's does, not to mention the time it would take to get there and back.
Why not first explore and exploit Near Earth Asteroid's (NEA's)? These are resources that are easy to get to, easy to return from, and which potentially contain extremely valuable resources. In addition if a space elevator were ever to be built, the logical thing to do would be to grab an NEA, move it into earth orbit, and then spin out the elevator from it. While this process was ongoing the asteroid could be mined, used as a space station and base for instruments and telescopes, and could be studied, telling us a lot about the formation of the solar system. The key here is bootstrapping, finding ways to make each step along the path towards the ultimate goal of man's colonization of the solar system as profitable, or at least less unprofitable, as is possible. The desire for knowledge about our solar system or national pride will only take us so far, and as long as the desire for knowledge or national pride, is what drives the space program, it will always be a political football, kicked hither and yon by the powers that be. But as soon as someone finds a way to make money out of space, and especially out of manned space exploration, then we will see a massive acceleration in the rate of technological progress and the scientific discoveries that go along with it.
Perhaps therefore instead of asking whether we should invest in manned or unmanned space exploration at the moment perhaps a better question is, what is the best way of making money out of space? If we concentrate our investment in those areas, providing seed money and incentives such as the X-Prize, to those who think they can make a profit from the void, then perhaps we can accelerate the current glacial progress of technological progress when it comes to launchers and finally move beyond von Braun to something a little more efficient.
While the desire to make a fast buck may not be as noble a motive as the desire to expand the sphere of human knowledge, we should not forget that the history of exploration and colonization here on Earth is the history of mercantilism and exploitation, albeit often with savage consequences for those who have been exploited. At least in space we shouldn't have that problem. Manned and unmanned space exploration go together, hand in glove, and we shouldn't rule out one in favour of the other. The real question is what is the most efficient way of getting out there, and the answer to that is to take the project out of the hands of the bean counters, bureaucrats and politicians and into the hands of those driven by that most basic of human desires, greed. While businessmen and corporations may not be paragons of human virtue, at least they have a tendency to get things done, because if they fail they cannot hide behind walls of bureaucracy and political manoeuvring, instead they go bust, and the technology and patents they have developed are snapped up by their competitors to be used again, rather than disappearing into the governments' archives, never to be seen again. We will get out there someday, but as long as the space program is a slave to the whims of government, of national expediency, of the military, and indeed of science, it will be a long, long road with many switchbacks, reversals and pauses, and I for one could do with rather less white elephants sitting in the middle of the road.