By Nick Davidson
From his office in Nevada, entrepreneur Dennis Hope has spawned a multi-million-dollar property business selling plots of lunar real estate at $20 (£10) an acre.
Humans are going back to the Moon
Mr Hope exploited a loophole in the 1967 UN Outer Space Treaty and he has been claiming ownership of the Earth's Moon - and seven planets and their moons - for more than 20 years.
These are "truly unowned lands", he says. "We're doing exactly what our forefathers did when they came to the New World from the European continent."
Hope says he has so far sold more than 400 million acres (1.6 million sq km), leaving a further eight billion acres still up for grabs.
Buyers include Hollywood stars, large corporations - including the Hilton and Marriot hotel chains - and even former US presidents Ronald Reagan and Jimmy Carter. George W Bush is also said to be a stake holder.
Mr Hope claims to be selling 1,500 lunar properties a day. He allocates land by simply closing his eyes and pointing to a map of the Moon.
"It's not very scientific but it's kinda fun," he says. It is fun that has already made him $9m (£4.5m).
No government has yet recognised the lunar sales as legally binding
The next race to exploit the Moon was started by President George Bush in January 2004, when he committed the US to returning to the Moon by as early as 2017.
He said the US aimed to establish a long-term lunar base by about 2020.
"We're talking about not just going there to stay three days," says Nasa rocket engineer Dr John Connolly. This time, he says, "we're talking about the idea of learning to live there."
Other countries are also making plans.
China - which has already successfully launched two manned space missions - has announced a similar timetable.
Russia, for nearly 50 years one of the world's leading space powers, may not be far behind. Europe, Japan and India have also expressed an interest.
Behind all this lies a growing belief that, within a matter of decades, the Moon will be much more than a scientific outpost; it could become a vital commercial frontier.
Large private companies and rich entrepreneurs have also seen a new business opportunity.
One of the biggest is US space contractor Lockheed Martin, which is currently developing technologies that will enable future lunar residents to exploit the lunar surface.
In particular, it is working on a process which will convert Moon dust into oxygen and water. It may even be able to turn it into rocket fuel.
"Just like we use resources here on Earth in order to live off the land - you can do the same thing on the Moon," says Lockheed Martin's Dr Larry Clark.
But this is peanuts compared with what scientists believe is the real prize lying in the moon rocks.
Mining the Moon
Data collected from the Apollo Moon landings have indicated that large deposits of an extremely rare gas called helium 3 are trapped in the lunar soil.
Scientists believe that this helium 3 could be used to create a new source of almost inexhaustible, clean, pollution-free energy on Earth.
One of them is Dr Harrison Schmitt, a member of the 1972 Apollo 17 mission and the only trained geologist ever to walk on the Moon.
Mr Schmitt was in a "geologist's paradise" walking on the Moon
"A metric ton of helium 3 would supply about one-sixth of the energy needs today of the British Isles," he claims.
Plans are already afoot in the US and Russia to strip-mine lunar helium 3 and transport it the 240,000 miles (385,000km) back to Earth.
The Moon, claims Professor Jerry Kulcinski of the University of Wisconsin-Madison, could become the Persian Gulf of the 21st Century.
"If we had gold bricks stacked up on the surface of the Moon, we couldn't afford to bring them back. This material - at several billion dollars a tonne - is what makes it all worthwhile."
Not everybody is happy with the idea of exploiting the Moon.
Edgar Mitchell was a member of the 1971 Apollo 14 lunar mission. He is worried that, in our rush to exploit it, we could also destroy valuable scientific information.
"As far as how the Universe works, we're just barely out of the trees. Until we know what the Moon is really all about, the idea of trying to commercialise it is, in my opinion, a misplaced idea," he argues.
Yet, he is almost a lone voice.
"The Moon is such a rich scientific destination, I think we need to look at it just the way we do the South Pole," explains Dr Connolly.
"We should go there, find everything there is to find out scientifically. There are a number of resources that we know can be of great benefit."
Horizon: Moon for Sale will be broadcast on BBC Two on Tuesday 10 April at 2100 BST.