What's special about the Moon?

What exactly is the Moon, and what’s up there for us in the first place? Adam Murphy spoke to Lewis Dartnell from the University of Westminster about our nearest celestial neighbour...

Adam - The moon has fascinated us since time immemorial. Formed as leftover debris from a primordial collision, our biggest natural satellite holds a special place in all our hearts. But we haven't been back since Apollo 17 in 1972. However, new missions are sending humanity back to the moon. But what's there for us? I spoke with Lewis Dartnell from the University of Westminster about what is actually up there for humanity.

Lewis - Well what we've learnt from the Apollo missions in the late 1960s and early 70s, when we're able to go to specific locations on the moon surface and bring back rocks, bring back geological samples back to the earth that we can study, is the astonishing thing is that the rocks on the moon are very, very similar to the rocks on earth. At least their composition of different elements and isotopes is very, very similar to the earth. So that's why we think, that's one of the best pieces of evidence we have, that the earth and moon have both come from the same basic mixing pot, as it were. Although the exact kind of rocks and minerals we find on the moon are exceedingly bone dry, far drier than any of the rocks we find on earth, because earth is covered with this lovely thick atmosphere and deep oceans; the moon is exceedingly dry in comparison.

Adam - So if moon rocks are like earth rocks - and we've got plenty of earth rocks down here - what's up there we might want?

Lewis - The sort of things that we talk about, in terms of in situ resource utilisation - which is just kind of space talk, that's kind of nerd talk for living off the land - if we're trying to send humans to survive on the moon in lunar colonies or lunar habitats, we're going to have to find things on the moon that we need to help us survive there. So things like water ice near the poles will be very useful in the moon for not just drinking water for astronauts and a moon base, but also splitting that water, spitting that H2O to give off oxygen, which you can use for breathing. But we also think there are things which have an inherent value on the moon that we could export from the moon back to the earth. And these sort of resources would be metals which are either rare or hard to mine effectively on the earth, things like platinum or tungsten, or they might be other resources which we haven't started using on the earth. And one of these resources would be something like Helium-3. And we think that Helium-3, one of the isotopes of helium, would be the ideal fuel for nuclear fusion reactors.

Adam - But what is it that's bringing us up there again? And why now?

Lewis - Another very good reason to go back to the moon would be effectively as a stepping stone on our journey, on humanity's path out to the planets. And the next logical step would be to start sending humans to Mars and perhaps trying to establish some kind of human presence there. But Mars is just so much further away than the moon is. And if you are an astronaut in a human colony on Mars and you have some kind of emergency, maybe some of your technology on the base keeping you alive starts malfunctioning, maybe you have some kind of medical emergency, you would have to wait perhaps several months before the Earth and Mars start lining up in their orbits so you could launch to come back home. And what we would therefore want to do before we start attempting a long-term human habitation on Mars is to learn all of our lessons and make sure we can get things right on what is effectively our own front doorstep, on the moon. So the moon in that sense represents a much closer, safer place - a test bed, if you like - for all the technologies and tools we'd need for exploring Mars and then out through the rest of the solar system.

Adam - And does Lewis see a future in which humans are living on the moon long-term?

Lewis - I do. It's something that, within my own research of astrobiology and space exploration, it's something I think would be very, very exciting and something very important for humanity to do. To start spreading beyond our own planet, look beyond into new horizons, start establishing a permanent human presence on the moon, possibly Mars, possibly out through the asteroid belt, maybe mine these places for useful stuff to support human civilization back on our home world.