When Neil Armstrong stepped out onto the Sea of Tranquillity in that historic summer of 1969, the science fiction writers had already been there for two thousand years. But history is always more imaginative than any prophet: no one ever dreamt that the first chapter of lunar exploration would end after only a dozen men had walked upon the Moon.
Yet it was not the first time that ambition had outrun technology. In the Antarctic summer of 1911-12, ten men reached the South Pole, and five returned. They used only the most primitive of tools and energy sources — snowshoes, dog sleds, their own muscles. Once the pole had been attained, it was abandoned for nearly half a century. And then, in the International Geophysical Year (1957-58), humans came back with all the resources of modern technology — and they stayed. For more than 40 years now, summer and winter, men and women have been living and working at the South Pole.
So it will be with the Moon. When we go back, it will be in vehicles that make the Saturn V look like a clumsy, inefficient dinosaur of the early Space Age. And this time, we will stay — and slowly extend onward to the planets, beginning with Mars.
But instead of using rockets to get us off the Earth, says Clarke, let's try a different plan this time, one that dates back to 1960.
I would urge NASA to keep investing at least a small proportion of its substantial budget in supporting the research and development of alternatives to rockets. There is at least one idea that may ultimately make space transport cheap and affordable to ordinary people: the space elevator.
NASA is investing a small portion of its research budget in "crazy" ideas like this. Through their Institute for Advanced Concepts (NIAC), they have supported the remarkable work of Brad Edwards, for example, as well as inventive nanotechnology design ideas jointly developed by CRN's Chris Phoenix, and Tihamer Toth-Fejel of General Dynamics.
The space elevator was the central theme in my 1978 science-fiction novel The Fountains of Paradise (soon to be a Hollywood movie). When I wrote it, I considered it little more than a fascinating thought experiment. At that time, the only material from which it could be built — diamond — was not readily available in sufficient megaton quantities.
Current space elevator proposals generally envision carbon nanotubes (C60) as the primary material for the cable(s). It will be several years, however, until the stuff can be produced in sufficient quantity to begin actual construction on the elevator. By that time, it's possible that Clarke's original material -- diamond -- may be easily and cheaply supplied in bulk by nanofactories.
As its most enthusiastic promoter, I am often asked when I think the first space elevator might be built. My answer has always been: about 50 years after everyone has stopped laughing. Maybe I should now revise it to 25 years.
Let's see, that would be around 2030 (since we don't hear much laughter anymore). Could it happen even earlier? Some people, like the Liftport Group, think so -- they project the first space elevator lift to occur on April 12, 2018.
I've already purchased a ticket.
UPDATE: On October 4, 2006, the Liftport Group announced that they have developed a preliminary roadmap [PDF] for building the space elevator, and they thay have pushed back the projected completion date from 2018 to 2031.