The internet has made some men so rich and ambitious that Earth no longer seems large enough to contain their fortunes – or their egos. That is the simplest explanation for the revival of interest in space exploration. But exploring space has always been a noble and inspiring pursuit undertaken for motives that are neither. The first space race, which culminated in the moon landings, was also a struggle for military advantage. This was not just a matter of ballistic missile technology, important though that undoubtedly was. There are at least 350 military satellites orbiting the world today. The ubiquitous GPS system was developed for military purposes. If the moon has been largely abandoned, this is because it has no economic or military use, although the romantic allure that pulled the first astronauts there has not diminished, and may in fact be strengthened by the magnificent uselessness of standing on the moon.

The second space race, undertaken by such men as Jeff Bezos and Elon Musk, is justified with some extraordinary rhetoric. Mr Musk, for example, promotes his SpaceX enterprise as something that is needed to save humanity from the extinction that must threaten us if we stay on one planet. It is of course possible that a nuclear exchange, guided and facilitated by the achievements of the first space race, could destroy all human civilisation on Earth and possibly all human life here as well. But a colony on Mars could hardly survive without constant contact and reinforcement from Earth, and even if it had developed to the point where it might do so, it would – as science fiction writers rightly suggest – still be full of human beings as short-sighted and quarrelsome as those who had destroyed their original home. The universe is mindbogglingly big, as Douglas Adams observed, and it is expanding very fast but it will never get fast enough that we could leave all our imperfections behind.

There is an economic rationale to these private space programmes: SpaceX is now a profitable company, despite the fiery death of its most recent launch. There is also a propaganda point made by some libertarians as a result of this economic success: that private enterprise can accomplish things that governments no longer can. The effectiveness of this argument is little diminished by the fact that it is not true: just as with the human genome project, the private competition builds on and relies on the publicly funded work. But it is quite clear that what drives the second space race is not really economics; there are much more effective ways to make money. Neither is it altruism in any obvious sense. If the real purpose were to relieve human suffering, even the Tony Blair Faith Foundation might be a more useful way for a rich man to spend his money. The real reason is the inexplicable but hugely powerful human desire for exploration and adventure, and to surpass anything that anyone else has achieved in those fields.

We go into space to advance the frontiers of science and to provide a new perspective on humanity’s place in the universe. In doing so, we fuel scientific curiosity and inspire generations. Billionaires may be leading that charge, but Pluto is not just for the plutocrats. A better solution may be a collective one: The UN “Office for Outer Space Affairs” is offering space trips for nations that can’t afford them. Camels might have to pass through an eye of a needle, but it would be better if the heavens were not just left to rich men.