The Russians are testing people for the flight to Mars, and the US needs to show leadership — because a vibrant nation explores or expires. We could have people on Mars in the early 2030s, but not if we sit around doing nothing. We need to take the lead on an international mini-shuttle that could be used on European, Indian or Chinese rockets. And we need to see a whole lot more sharing of our different experiences.

I believe that a mission to Mars would need a commitment to a permanent settlement of people who have signed up to spend the whole of their career on the planet. Otherwise the programme risks being cancelled after one or two missions.

Such a settlement would eventually be able to live off the resources there, which are far more plentiful and supportive of human sustenance than on the Moon. Mars has a little bit of an atmosphere and some ice under the dust and at the poles.

There would be great pressures for the crew — you don’t out and out say that we’re going to Mars on one-way trips because that shocks people. But we are talking about pilgrims, the sort of people who left your country on the Mayflower. My sense is that thousands would jump at the chance to be the first settlers.

Would I want to go? I’ve given it a lot of thought, and I think I’m a bit more of an analytical person — and survival on Mars is going to be pretty basic. Sending men to Mars will be a long journey in every sense. We don’t have to take all the decisions now. But we need to make a start.

Magnificent Desolation: The Long Journey Home from the Moon by Buzz Aldrin Bloomsbury, £16.99

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