Could space-going billionaires be the vanguard of a cosmic revolution? | Martin Rees

For humanity truly to slip the surly bonds of Earth, private funds and intrepid thrill-seekers will be required

• Martin Rees is the astronomer royal

I'm old enough to have watched the grainy TV images of the first moon landings by Apollo 11 in 1969. I can never look at the moon without recalling this heroic exploit. It was achieved only 12 years after the first object, Sputnik-1, was launched into orbit. Had that momentum been maintained, there would surely have been footprints on Mars a decade or two later. That's what many of our generation expected. However, this was the era of the space race between the United States and the USSR, when Nasa absorbed up to 4% of the US federal budget. Once that race was won, there was no motivation for continuing this huge expenditure.

To young people today, these exploits are ancient history. Yet space technology has burgeoned. We depend on satellites every day, for communication, weather forecasting, surveillance and satnav. Robotic probes to other planets have beamed back pictures of varied and distinctive worlds; several have landed on Mars. And telescopes in space have revolutionised our knowledge of the cosmos. What's more, humanity, or rather a narrow sliver of us, may be on the verge of an era of space exploration that makes the moon landings seem parochial by comparison.

Martin Rees is the astronomer royal and a former president of the Royal Society. His new book, co-authored with Donald Goldsmith, is The End of Astronauts: Why Robots Are the Future of Exploration