We took a step nearer to the realm of classic science fiction this week with the launch of this year's second asteroid-mining venture. One might be seen as eccentricity; two within a month start to look like a gold rush.
Deep Space Industries plans to launch three laptop-sized craft on asteroid flyby missions while its rival, the even more grandiosely-titled Planetary Resources, intends to send a fleet of small craft into Earth orbit, a posse of tiny prospectors looking for that elusive glint of something valuable in passing rocks.
It certainly makes a change from seeing asteroids merely as incoming missiles and a threat to humanity, though those of an apocaholic disposition might enjoy contemplating the potential risks of trajectory perturbation caused by mining activities.
While the economist sensibly points out that, should vast reserves of platinum be a) discovered and b) brought back, the resulting depression of the markets would affect the long-term profits of the operation, DSI's David Gump ultimately has his eye on higher things.
Mining metals in space and constructing spacecraft components in orbit would eliminate the need for materials to be brought out of Earth's gravity well at great expense. Even more conveniently, ice from asteroids and comets could one day fuel the next generation of space exploration.
Add in inventions such as the inflatable living module that can be shot into space compressed into a 7-foot tube and suddenly the visions of Arthur C Clarke, James Blish et al. don't seem so far away any more, though with advances in robotics, I doubt we will ever see independent space prospectors like the husband-and-wife team in Bertram Chandler's short story, 'The Half Pair' (which, incidentally, contains one of my favourite sci-fi quotes: 'Spaghetti and free-fall don't mix').
And with advances in carbon nanotechnology keeping pace, future generations may yet see the much-debated space elevator constructed on the moon or Mars. Perhaps DSI's Firefly craft and their larger Dragonfly successors will herald the beginning of a new age in extra-terrestrial activity.
After all, at the start of the Californian gold rush, who would ever have believed that some of that gold would one day be an essential component of the lunar landing module?