'Tsien has landed right beside one of these white streaks – the fifteen-hundred-kilometre-long feature that's been christened the Grand Canal. Presumably the Chinese intend to pump its water into their propellant tanks, so that they can explore the Jovian satellite system and then return to Earth. That may not be easy, but they'll certainly have studied the landing site with great care, and must know what they're doing.

'It's obvious, now, why they've taken such a risk – and why they claim Europa. As a refuelling point, it could be the key to the entire Solar System...'

But it hadn't worked out that way, thought Sir Lawrence, as he reclined in his luxurious chair beneath the streaked and mottled disc that filled his artificial sky. The oceans of Europa were still inaccessible to mankind, for reasons which were still a mystery. And not only inaccessible, but invisible: since Jupiter had become a sun, both its inner satellites had vanished beneath clouds of vapour boiling out from their interiors. He was looking at Europa as it had been back in 2010 – not as it was today.

He had been little more than a boy then, but could still remember the pride he felt in knowing that his countrymen – however much he disapproved of their politics – were about to make the first landing on a virgin world.

There had been no camera there, of course, to record that landing, but the reconstruction was superbly done. He could really believe that was the doomed spaceship dropping silently out of the jetblack sky towards the Europan icescape, and coming to rest beside the discoloured band of recently frozen water that had been christened the Grand Canal.