(Illustration by Michael Sloan)

Remember gazing up at the moon and wondering what it’s made of? Some pretty smart people are doing the same thing today. And it’s not childlike curiosity that’s motivating them: It’s money.

Interest in materials known as rare earth elements surged when China temporarily blocked exports in 2010. Manufacturers started looking everywhere for new supplies of gadolinium and terbium and other elements used in televisions, hybrid car batteries and many other products. The search took them to such places as California, the Pacific ocean floor and the moon. The moon’s stock is up even among politicians, as Newt Gingrich and Mitt Romney recently sparred over whether it makes sense to invest in lunar mining.

Rare earth elements aren’t the only potentially valuable resources on the moon. Helium-3, an isotope that in the future may support cold fusion when earthlings finally figure out how to make it happen, is another potential treasure. Helium-3 is a component of the solar wind, which is constantly blowing outward from the sun. Our atmosphere blocks helium-3 from reaching Earth’s surface. The moon doesn’t have much atmosphere, so scientists speculate that there may be more than a million tons of the isotope up there.

Ready to grab your moon pick, pull on your moon boots and heigh-ho your way into a moon mine? Not so fast. There’s a vast amount of research that needs to be done first.

For starters, scientists say, we need to figure out where the moon came from and what it’s made of.

“Although we broadly know the composition of the moon, it’s slightly embarrassing to admit that the exact origin and evolution is not totally tied down,” says John Zarnecki, a professor and space researcher at Britain’s Open University.

The dominant theory is that a Mars-size object struck Earth 4.5 billion years ago, breaking off a bunch of material that melded together to form the moon. If this theory is correct, we can expect that the moon is made of roughly the same chemical building blocks as Earth. The 1,500 or so pounds of material that U.S. and Soviet explorers brought back from the moon during the 1960s and 1970s provided some support for the theory.

NASA sent up an imaging spectrometer called the Moon Mineralogy Mapper on an Indian rocket in 2008. A mechanical failure cut the mission short, but it did provide evidence that there is water on the moon. It also suggested that the moon was once molten. That’s an incredibly important finding because it’s not enough that the moon contain valuable resources; any hope of mining them requires that they be concentrated so that they can be extracted from a small number of locations.

While the moon doesn’t have as broad a range of geologic processes as Earth — there is no indication of plate tectonics, for example — the cooling-down of a molten rock would help to sort the minerals. Different materials would settle and solidify at different layers.

That’s just a start, though. It will take much more research to find the most concentrated deposits of whatever resources exist.

Once the scientists get all of this sorted out, it’s time for lunar mining to begin. China, India and Japan have all indicated an interest in setting up moon mining operations. Google and NASA have each offered a $30 million prize to the first private company to put robots on the moon.

Naveen Jain is co-founder and chairman of Moon Express, one of the companies vying for the prize. A former executive at Microsoft, Jain is so enthusiastic and confident about moon mining that talking to him makes you wonder why we haven’t been doing it for years.

“We already have much of the technology. We know how to get into Earth orbit, how to land on the moon, and how to return to Earth. There are only a few key problems to solve,” he says.

According to Jain, NASA is collaborating with Moon Express on a lunar lander that is being tested at NASA’s Ames Research Center in California. The lander is intended to hop and hover, which Jain says is the best way to move long distances around the lunar surface. (To understand why, consider NASA’s rover Spirit, whose wheels got stuck in the Martian soil in 2009 and never got out.) Jain is hoping to send the vehicle to the moon on a rocket built by SpaceX, another private foray into the space business, in late 2013 or early 2014.

Moon Express or any other group faces several challenges if it’s to establish a long-term robotic mining operation on the moon. (Few in the industry are talking about founding a human colony anytime soon, Gingrich’s ideas notwithstanding.)

First, there has to be a way to power the operation.

That’s where the water comes in. Lunar water could be split into hydrogen and oxygen for fuel cells, similar to the hydrogen fuel cells that car manufacturers are trying to develop. “The moon could represent a gas station in the sky,” Zarnecki says. That gas could fuel other space missions in addition to lunar mining.

Another major problem is economics. Jain thinks he can land his hovering rover on the moon for less than $100 million. Part of that is coming from private investors and part from a contract with NASA. But he also has some ideas about how to earn some money before the mining operation is up and running.

“Once you’re on the moon, all sorts of opportunities arise,” he says.

“What if you could pay $30 or $40 to drive a remote-controlled lunar rover around for a few minutes using a Web-based platform? What if I could write messages — like a wedding proposal — onto the lunar surface and send you a digital picture for $50? These things add up quickly. Mining isn’t the only potential revenue source on the moon.”

Another challenge is the legality. No country, corporation or individual owns the moon. That hasn’t been an issue, because only a minimal amount of material has ever been removed from it. But that’s going to change when the mining starts. Jain draws an analogy to the sea.

“No one owns international waters, but those who invest their money and effort to find fish are entitled to profit,” he says. It’s an intriguing analogy but untested in any court.

The lawyers better start working on their arguments: Jain says he plans to start mining in earnest by 2016, although that timelime is incredibly ambitious, to say the least. And China has announced plans to bring back small amounts of lunar rock by 2020 in advance of a manned mission and lunar mining several years later.