AS VOTERS in space-mad Florida consider their options in tomorrow's Republican primary they may wonder if Newt Gingrich's idea for a moon base is a shameless appeal to their parochial interests. But they'd be wrong to doubt his sincerity. For nearly three decades Mr Gingrich has been touting space colonisation; he co-founded the Congressional Aviation and Space Caucus and wrote a book that called for more space exploration. He is as space mad as the Floridians he hopes to win over. But that raises another question: how mad is this idea?

That depends. The idea for a moon base was a feature of George W. Bush's space policy. But there is a world of difference between sending small groups of astronauts to a lunar base for months at a time, as Mr Bush envisioned, and having tens of thousands of people living permanently on the moon, as Mr Gingrich envisions.

Sending half-a-dozen people to the moon might be done for less than $100 billion. The necessary rockets already exist, or could soon be developed. The existing Atlas V could be rated for human use. Or one might use the Falcon Heavy, due for launch next year by SpaceX. Elon Musk, the CEO of SpaceX, says that the recurring costs of the Falcon Heavy are around $100m per flight, but they are confident they can make part of this craft reusable and bring the cost down to $2m-$3m, assuming a high flight rate. With seven astronauts per lunar flight, the cost per person to the moon would be around $700,000. So in theory, one might be able to transport 15,000 people to the moon for around $10 billion. Not bad.

Of course, you can't touch down on the moon without a lander, and you can't live there without a base. But it turns out that both could be developed from the inflatable space habitats currently being flown by the company Bigelow Aerospace. (Full disclosure: your correspondent paid to send a small vial of her father's ashes on Genesis II, a Bigelow inflatable spacecraft that as I write is currently orbiting just north of me in Canada.) Inflatable habitats can be set up in low-earth orbit (LEO), tested and then landed intact on the moon using specialised propulsion modules. In this scheme the only thing needed would be a new capsule to take astronauts up into LEO, which is not a stretch.

Technologically, then, it is feasible to get 15,000 people onto the moon for the kind of money that exists in America's treasury. But then things start to enter the realm of fantasy. Initially most food for the lunar colony would have to be part of regular cargo delivery—the way they do it on the International Space Station. Mike Gold, head of Bigelow's Washington office, jokes that if America waits too long they'll be able to "order out for Chinese". But realistically, it will become necessary to work out how to create a closed-loop ecological system—where everything is recycled, reused and entirely sustainable. Energy must be renewable. Food must be grown, waste water must be reused and the air must be kept clean. In other words it would resemble the sort of crazy liberal fantasy that drives Republicans nuts on Earth.

Even if it were possible to feed, clothe and keep alive 15,000 people, if Moon Base Gingrich (MBG) is not to become the largest federal money suck in history it needs to actually produce something that Earth wants to buy. Something has to be mined, and shipped back to Earth, in an economically viable way. Enthusiasts talk of helium-3 mining and rare-earth metals, but who knows? That's something President Gingrich will want to find out before sending all those people up there.

Most importantly of all, as MBG pursues statehood, we must consider whether it will swing Republican or Democrat. Lets think about this, the population will be highly educated, eco-friendly and very likely dependent on vast government support. Perhaps Newt has gone mad.

(Photo credit: AFP)