The discovery of water on the moon has opened up an exciting new universe of space travel possibilities. But while Nasa focuses on the practicalities of lunar living, the Japanese have set their sights on complexes with tennis courts - and even golf courses

SUDDENLY the fantasy of space tourism no longer seems far-fetched. Imagine the brochures: "Tan in gamma-ray glory on the powdery beaches of the Sea of Tranquillity!" "Eat all you want and watch the pounds float away!" "Explore unspoilt nature by day and, when the sun sets and planet Earth rises in the north, dance the night away with the stars!" "Golfers, bring along your clubs: don't miss the opportunity to hit the longest drive of your life!"

Nasa's discovery that there is water on the moon opens up a new universe for vacationers seeking a change from the banality of holidays in Torremolinos, adventure cruises down the Orinoco or climbs up Mount Everest. Scientists monitoring the data received from the unmanned Lunar Prospector spacecraft said last week that ice found in the craters on the moon's north and south poles indicates the existence of between 10 and 100 million tons of H20 - enough, according to one of the scientists, to support "a modest amount of colonisation for many years".

We're talking seriously about living on the moon. One of the many benefits of discovering water is that a spacecraft flying to the moon would be able to refuel for the trip back much as a jumbo jet does before making the flight from, say, Miami to London. The moon's ice could be converted into the liquid hydrogen and liquid oxygen to make the same brand of rocket fuel that powers today's space shuttle. The ice could also be converted into water for drinking, and oxygen for breathing. Once that has been accomplished, the possibilities are almost boundless.

Nasa has already been toying with the practicalities. Its Advanced Life Support Programme at the Johnson Space Centre provides scientists with opportunities to develop the technologies to sustain human life on the moon. In an image of what a lunar hotel suite might look like, Nasa has converted a giant cylindrical centrifuge once used to test astronauts' mettle into a two-storey mock-up of a space residence - complete with a small kitchen and small breakfast and office rooms. Nasa scientists say they deliberately wanted to make the model look like home.

As for food, the Nasa project envisages the prospect of growing fruit and vegetables, including wheat for bread-making, aided by the rich nutrient qualities of recycled human urine and faeces. In order to introduce some protein into the lunar diet, livestock could also be reared on the moon taking advantage of the developments in cloning technology.

Given the ferocity of the solar winds and the brutal temperature swings on the moon - from -200C to 200C - plant life as we know it could only flourish in a greenhouse environment. Human life and human living quarters might need protection from the elements, too, as might the cattle if the peril of a dangerous new strain of lunatic cow disease is to be avoided.

This is why lunar lava tubes are important. These are natural caves, or tunnels, which are thought to have been formed millions of years ago by volcanic activity. Some space geologists believe that one such tube on the Aris Tarchus Plateau runs half a mile deep and spans an area 65 miles long by three miles across. Typical lava tubes are several hundred metres wide.

Protected from the solar winds and safe from the ever-present lunar danger of flying astral debris, the temperature inside these underground valleys is a cosy -20C. This is where the hotels, restaurants, indoor bowling alleys, golf courses would be built. Light, of course, would be provided by solar energy, catering to the plants' photosynthetic needs and providing the power for a new range of lunar leisure vehicles - golf buggies, perhaps, or modified Land Rovers.

Upmarket clients scornful of the modest environment imagined by Nasa's cylindrical suites may wish to explore the five-star options being contemplated by a number of Japanese building companies which have established divisions to conduct moon-based construction research. Three of the biggest have spent some $40m (pounds 25m) on these futuristic projects. One of them, named Shimizu, has plans to build condominiums complete with tennis courts and, yes, golf courses. Each condominium would consist of a cluster of inflatable egg-shaped dwellings four storeys high. A Shimizu brochure observes, shrewdly, that inflatable buildings "could reduce transportation costs".

More ambitious is a project conceived by Nishimatsu Construction Corporation, which plans to build what it calls Escargot City on the moon. This is a resort consisting of three 10-storey inflatable towers shaped in the form of snails' shells. The central tower, as shown in a model, would be Hotel Nishimatsu, complete with conference rooms and Las Vegas-style flashing neon signs.

A senior Nishimatsu researcher, Kazuo Kurihara, last year explained the company's interest: "Nishimatsu is a construction company and our philosophy is to go far into the sea, deep into the ground and high into the sky." Unaware or unimpressed - or both - by the lava-tube option, Nishimatsu anticipates building its holiday complexes in the open lunar air. In order to prevent a moon tour from becoming an expensive way of committing hara-kiri, Mr Kurihara explains that the company is developing special anti-radiation wall material that will protect visitors from the fatal risks of prolonged exposure to gamma rays.

Even before Lunar Prospector set off on its historic mission to divine water on the moon another Japanese company, Obayashi, was working on an extravagant project to create a self-sufficient lunar community of 10,000 people nourished by the harvests of vast vegetable moon farms.

MADNESS, maybe, but now we know there is water on the moon it is no longer pie in the sky. There is a market for it already in the US, although the new Columbuses

will most likely start by establishing the first outposts in space rather than on the surface on the moon. Buzz Aldrin, the second man on the moon, said recently that he expected to see space hotels in his lifetime. And, having patented his own space-ship design, the 68-year-old former astronaut is hoping to cash in.

He is not the only one. All over America a new breed of entrepreneurs sees dollar signs in the heavens. A company in Houston is already cashing in. In the past year Celestis Inc has sold space on two rockets for the cremated remains of 30 people, charging $4,800 a turn. Celestis has plans to provide a more accessible service to those who would dispatch their DNA and accompanying photo into the outer reaches of the solar system. The charge would be a mere $50 a shot.

But the big money will be in sending flesh-and-blood humans into space. There will be no shortage of wealthy Americans ready to part with the $98,000 Zegraham Space Voyages of Seattle are asking for a passenger ride beyond the earth's gravity. "If a journey to space has been one of your life's great dreams, this is the trip for you," enthuses Zegraham's "Adventure Travel to Space" brochure.

Zegraham offers a seven-day package: six days of training on earth prior to a three-hour round trip 62 miles above the planet's surface. A mother ship called the Sky Lifter would take off from a regular runway. At 50,000 feet a small, six-passenger plane with a pilot and a co-pilot aboard would peel off from the mother ship. A burst from a rocket would take the plane outside the stratosphere, providing the holiday-makers with a fleeting, three- or four-minute opportunity to make some unforgettable home videos, prior to re-entry and a hopefully safe landing under jet power on the runway from which the mother ship took off. The first trip is planned for 1 December 2001. The brochure promises that there will be a toilet aboard.

In the light of Nasa's latest discovery, however, Zegraham's travel offer, to which 25 people have so far subscribed, suddenly seems lame and unambitious. It's one thing to travel, another to arrive on the lunar surface. The price of a three-day-there, three-day-back trip to the moon with, perhaps, a week's stay at the Lunar Hilton in between, might only be within reach for Bill Gates and the Sultan of Brunei. But give it time and who knows? When the Queen was born her parents would scarcely have imagined that the royal stable boys would one day be able to afford a return air trip to Miami.

Tourism means colonisation, of course, and with that comes politics, and possibly rebellion. In The Moon is a Harsh Mistress the science fiction writer Robert Heinlein describes a moon-inhabiting people - known, naturally, as Loonies - who are oppressed by the imperial authorities on Mother Earth. They rise up, igniting a revolution whose unlikely slogan is, "There ain't no such thing as a free lunch".

It's a plausible consequence of life on the moon: some centuries down the line, a Lunar Boston Tea Party?