In 1727, seven years after the South Sea Bubble burst, the pseudonymous Captain Samuel Brunt published an account of his visit to Cacklogallinia, an island ruled by talking chickens. In a quest for unearthly riches, Brunt, using the power of birds, travelled to the Moon, where he was dismayed to discover that it had already been colonised by human souls who rated universal harmony higher than individual power and wealth. Such utopian sentiments are not commonly found among today’s space pioneers. Elon Musk reportedly believes that by 2035 a million people will be settling into life on Mars, while Jeff Bezos’s Blue Origin consortium has already won mega-contracts from NASA to develop a lunar transport service. Others have turned their attentions to the potential of space for providing materials that are scarce and hard to extract on Earth. Nereus, an asteroid only five hundred yards long that periodically passes close to Earth, promises vast quantities of platinum and other rare metals.

As the astrophysicist David Spergel has observed, ‘our history as humans has shown that first we screw things up, and then we make some things right.’ Two other distinguished scientists, Donald Goldsmith and Martin Rees, have taken his message to heart. In The End of Astronauts, they make