It would seem that money can't buy you love, but it can buy you a great view. Five years ago today, California millionaire Dennis Tito paid for a seat on a Russian Soyuz rocket that took him for a stay on the International Space Station. Tito became the first paying astronaut - but what about the rest of us? Five years on, are we any closer to swapping our sun hats for space helmets?
Some others have followed Tito. South African businessman Mark Shuttleworth made the trip a year later, and US millionaire Gregory Olsen was space cadet number three. Japanese businessman Daisuke Enomoto is next up this September, followed by Charles Simonyi, a former development guru at Microsoft. None of these people is poor - each forked out around $20m for an eight-day trip.
Still, even at those prices, things have moved on a great deal since the Cold War, when space exploration was dominated by big government. The Apollo moon programme cost $100bn in 1990s money. Today's entrepreneurs hope to use private-sector efficiencies to slash prices for space tourism in the next few years.
"The private sector is motivated by profit and efficiency and the US government often is not," says Eric Anderson, CEO of Space Adventures, which arranged flights for the five intrepid travellers who have made the voyage into space so far. But then, if it wasn't for big, heavy government technology, Anderson wouldn't be taking tourists into space at all. Space Adventures brokers deals between wealthy tourists and the Russian authorities, buying them spare seats on existing Soyuz flights.
And it's little wonder Anderson is hitching a ride rather than building his own vehicles. Spacecraft must accelerate to 17,400mph to get into orbit, and survive extreme heat on re-entry.
A cheaper alternative attracting research and development from private companies is suborbital space travel. Suborbital craft still make the 100km (62 mile) trip into space, but they don't get far enough to make it into a self-sustaining orbit. Rather, they travel for a short time before gliding back to earth. The difference between orbital and suborbital flight is huge; suborbital craft need to reach only 3,000mph.
Virgin Galactic was set up by the Virgin Group in 2004 with the aim of beginning commercial suborbital flights in 2008. It is ploughing $240m into space tourism and has pocketed $14m in deposits from 158 would-be astronauts.
Last June, Virgin Galactic formed the SpaceShip Company, a joint venture with the aerospace company Scaled Composites, headed by Burt Ratan. Ratan made history in October 2004 when his suborbital vehicle, SpaceShipOne, became the first manned private craft to make it into space. By doing so, Ratan won the $10m Ansari X prize, an award funded by private donors who wanted to mirror the practice of encouraging early aviation innovators with the lure of prizes.
The SpaceShip Company now plans to sell SpaceShipTwo, which is designed to carry six passengers and two pilots. Virgin ordered five of them, along with two of the 757-sized launch carriers that carry the craft aloft before launching them into space.
In the meantime, Blue Origin is working on another suborbital craft. The company, founded by Amazon chief Jeff Bezos, will develop a series of crewed launch vehicles that will take off and land vertically. Expect flights in as little as five to six years.
But these craft don't make it into full orbit, which is bad news for Mike Gold, corporate counsel for Bigelow Aerospace, the skyward-looking venture of hotelier Robert Bigelow. Bigelow is moving into space accommodation with a series of pods that can be flown into space and inflated. The pods will keep out space radiation with walls a foot thick.
Bigelow is said to be spending £280m on the project, but if the means of getting his guests into space doesn't take off soon, his business could end up looking deflated. "We hoped that by the time we were getting within view of deploying our technology, the launch industry, whether X-33 or some sort of single-stage-to-orbit system, would have been well along the way, or that Soyuz prices would have dropped dramatically," says Gold.
The X33, a wedge-shaped successor to the Space Shuttle being developed by Lockheed Martin, would have been a completely reusable orbital craft - the holy grail for orbital flight. Generally rockets carrying a heavy payload shed it in three stages as they climb into orbit.
And SpaceX, owned by PayPal founder Elon Musk, wants to make conventional rocket designs cheaper using simpler engine models and reusable rocket stages that will be recovered after launch. "By starting a greenfield company, we can do it more efficiently," says president Jim Maser.
By piggy-backing on Soyuz missions, Space Adventures is at a disadvantage, warns Maser. As it doesn't own the technology, its costs could rise. Eric Anderson admits that costs are unlikely to fall soon, but SpaceX also has its problems. Falcon 1, its unmanned test craft, failed shortly after liftoff. Undeterred, the firm has planned more flights with commercial cargo, culminating in a manned mission on Falcon 9.
Suborbital space flight is a hotbed of innovation, but further out, progress has stalled. Here, tourists are riding the technology that fuelled Cold War nuclear missiles. Sightseers may look down on a brave new world, but for the time being, the technology that got them there comes from a much older one.
Final frontier: the facts about space tourism
A suborbital flight will take you into space 62 miles above the earth's surface for a short period. Virgin Galatic's flights, using SpaceShipTwo, will lift off from the Mojave desert until its New Mexico spaceport is complete in 2009.
Expect to pay $200,000 for a two-hour flight, during which you'll get five minutes of weightlessness. Virgin is planning a spaceport in Europe for trips through the northern lights.
In the future, Space Adventures promises you an exciting boost with the powerful rocket engines of a suborbital craft called Xerus, currently under development by aerospace company XCOR Aerospace. When the craft reaches its maximum 62-mile height, you'll get five minutes of weightlessness.
Space Adventures is the cheapest option for space day-trippers on a budget: $102,000 will get you up there in the Xerus. That includes $98,000 for the flight, with $4,000 for a cancellation plan. But don't worry - you can pay $1,000 per month for three years with a final lump sum payment.
For the moment, Space Adventures has the monopoly on orbital space travel. After being medically certified, you will train at the Yuri Gagarin Cosmonaut Training Centre 90 minutes from Moscow. Expect zero gravity sessions, physical instruction and survival training. You will orbit the earth every 90 minutes, and will have 30 hours in the orbiter before your rendezvous with the International Space Station.
By the time you leave the space station eight days later, you'll have been around the world 120 times. The cost: $20m.
Right now, there's only one option for accommodation, outside of your orbiter module: the International Space Station. Living alongside the crew for eight days, you'll eat space food, live in weightlessness and orbit 250 miles above the earth.
Budget hotelier Robert Bigelow could provide another option. When inflated, his hotel podsshould be as large as a three-bedroom house.
Space Services Inc has booked payload space on low-cost SpaceX flights and will transport your ashes into space. A gram of you can be taken into orbit for $995. Customers include actor James Doohan, who played Scotty in Star Trek.