If all goes well, American millionaire Dennis Tito will this year become the world's first space tourist, flying on the Soyez rocket to the International Space Station. The ticket price? A cool $20 million. But a new fueling system developed by Andrews Space & Technology of Segundo, Calif., could soon make space tourism far cheaper.

Known as Alchemist, the system, developed as part of NASA's Space Launch Initiative, harvests liquid oxygen from the atmosphere instead of carrying it from the ground, making a massive weight saving and slashing launch costs. A plane the size of a Boeing 777 is envisaged taking off from a civilian runway with an orbiter on its back. The plane flies around at about 8,000 meters sucking in and storing away air. Heat exchangers cool the air and a centrifuge separates out the oxygen. Once it's collected enough, after about three hours, the oxygen is combined with liquid hydrogen and the orbiter blasts off into space.

A conventional rocket's take-off weight is 90 percent fuel, and doing without liquid oxygen cuts the plane's weight by almost half. Moreover, the chances of an explosion are less because there is no chance of liquid oxygen mixing with liquid hydrogen. Takeoff would be horizontal, and passengers would sit in airliner-style seats.