On Wednesday September 29, a private company in California plans to launch a craft known as SpaceShipOne into near-earth orbit in an attempt to win the so-called "Ansari X-Prize." The craft was first tested successfully in a preliminary flight in June that approached the altitude needed for suborbital flight. This venture could be the beginning of a whole new, private-sector-driven era in space.

Until now, space flight programs in the United States have been the exclusive realm of the National Aeronautics and Space Administration, known as NASA. But private sector companies, working under NASA contracts, have developed most of the technology and built the rockets and vehicles.

Now, aircraft designer Burt Rutan, backed by billionaire and Microsoft co-founder Paul Allen, is trying to change that. He plans to win the X-Prize by sending his SpaceShipOne into suborbital flight twice within two weeks. The aircraft will carry only the pilot on these flights, but will be weighted as if three people were aboard in order to meet the requirements of the prize offering.

The chairman of the privately funded X-Prize Foundation, Peter Diamandis, in a recent congressional hearing, argued that, although the $10 million prize is an incentive, the real goal is something loftier.

"This is bringing out the human spirit, the need to achieve greatness, that goal, [for people] to do something meaningful with their lives. The U.S. government and NASA can do that and capture that level of enthusiasm and get the world excited," he said. "I want to see kids getting on the internet and looking at prizes to help shape what they do in their careers."

If SpaceShipOne succeeds in its mission, it could foster a whole new era in space flight history. Robert Oler, a co-founder of the Clear Lake Group, a private space advocacy group here in Houston, believes the time has come for private companies to take over much of the routine work NASA is doing with the international space station.

"Unless, very quickly, NASA gets out of the business of doing what private industry could do, we are stymied in human space flight," he says. "What private industry could do today, with competent federal policy, what private industry could do right now, is re-supply the space station and eventually re-crew it."

Mr. Oler says successful private space flights could also lead to a profitable new industry-taking paying passengers into space. "There is a desire among the American people to go out into space. Most of the people who went out [in June] to watch SpaceShipOne fly were not rocket scientists, they were not engineers, they were not mathematicians," he says. "They were people who saw this and thought, 'I could ride on that vehicle one day!'"

Lawmakers are now urging NASA to explore ways of getting more private sector involvement in space flight projects. Next year the agency will offer inducement prizes of up to one billion dollars under its Centennial Challenge program.

But there are also voices of caution. U.S. Representative Nick Lampson, a Democrat from Texas who is the Ranking Minority Member of the Congressional Science Committee says funding prizes should not come at the expense of the NASA budget.

"The establishment of incentive prizes should not be viewed as a substitute for adequate and sustained investment by the federal government in aeronautics and space R and D [Research and Development]," he said. "We need to support a robust NASA budget this year and in the years to come."

At the Johnson Space Center, south of Houston, former Space Shuttle astronaut David Leestma now heads NASA's Exploration Office. He says private sector involvement in space could be the way of the future. "I would love to see private industry being able to take passengers into space. Let Conrad Hilton open a hotel in space and have people vacation there," he says. "I think that would be wonderful."

But Mr. Leestma cautions, there are still many obstacles for private companies to overcome before they can do what NASA does. "I think it could possibly happen, but chemical propulsion and the turning of oxygen and hydrogen or some other fuel into the smoke and fire coming out the back to give you the acceleration and thrust you need to get the right velocity to get into orbit is a very dangerous thing and it is very expensive right now," he says.

David Leestma notes that NASA will always have a role to play in space exploration and in carrying out pure science experiments that hold no potential profit for private enterprise. He also expresses concern about legal indemnification for companies that could one day operate missions to the space station under a NASA contract.

"If we are flying government missions then the government is always going to be responsible, so NASA will be involved in those particular missions," says Mr. Leestma. "When it comes to private enterprise, I do not know if they can indemnify themselves or how that is going to work. There is probably a whole new realm opening up in space law."

Space flight enthusiasts in the private sector express confidence that such questions will be resolved. They note that most great endeavors involve risk and that most great accomplishments in the world of business also involved adventurous entrepreneurs putting their money and, sometimes, even their lives, on the line.