A halo forms around the top of the SpaceX Falcon 9 test rocket as launches from complex 40 at the Cape Canaveral Air Force Station in Cape Canaveral, Fla. A launch scheduled for Saturday will mark the first time a private company will send its own rocket to the orbiting International Space Station, delivering food and ushering in a new era in America's space program.

By KENNETH CHANG

c.2012 New York Times News Service

It sounds like a routine event for NASA: At 4:55 a.m. Saturday, a rocket is scheduled to lift off from Cape Canaveral, Fla., and carry cargo - but no people - to the International Space Station.

But if all goes as planned, that morning will mark something transformative for the space industry: a victory for capitalism in what has been for decades a government-run enterprise. The capsule, built by Space Exploration Technologies Corp. - SpaceX, for short - would be the first commercial spacecraft to make it to the space station, and many observers view its launching as the starting gun in an entrepreneurial race to turn space travel into a profit-making business in which NASA is not necessarily the biggest customer.

Already, there are some hints of how the era of commercial space travel might unfold. Companies like Virgin Galactic, XCOR and Space Adventures are booking passengers on suborbital joy rides to space, promised for dates within the next few years, and hundreds of people are signing up. And already there are celebrity tie-ins: Among the people who have signed up for Virgin's first flights are Ashton Kutcher, Angelina Jolie, Brad Pitt, Tom Hanks and Katy Perry.

On a more mundane note, the launching of commercial satellites has been a steady business for decades, and SpaceX is among the companies competing for contracts. Indeed, SpaceX already seems to have built a viable business here, having announced more than $1 billion of contracts in the past few years.

Then there are the longer-term dreams, which may sound less far-fetched as each landmark in space travel grows nearer.

"I think humanity needs to get to Mars, one way or another," said Elon Musk, the founder and chief executive of SpaceX, who vows that his company will send people to Mars in as little as 10 years - more likely 15 years, and certainly within 20. He said he would do this with or without NASA: "I would prefer it would be with NASA. If not, we have to find another path."

The International Space Station is only a couple of hundred miles up - SpaceX's rocket has yet to get there, of course - and Mars is millions of miles away. But Musk predicts that travel to Mars will eventually become commonplace, and that the ticket price will eventually - perhaps a decade after the first flight - drop to half a million dollars. That contrasts with the more than $60 million a seat that the Russians are currently charging NASA to take one astronaut to the space station.

"Is it possible to achieve that?" Musk said in an interview at his headquarters in Hawthorne, Calif. "I think it is. My calculations show that it is."

To date, space travel has been expensive and, as a government-managed operation, has had little incentive to streamline. NASA, of course, was the only game in town for U.S. astronauts, and most recently it operated the shuttles that supplied the International Space Station. Big aerospace has been involved, too: One company, United Launch Alliance, a joint venture between Boeing and Lockheed Martin, effectively has a monopoly for launching satellites for NASA and the Air Force on its Delta IV and Atlas V rockets.

Only recently have smaller, nimbler companies like SpaceX, some of them run by billionaires who proved themselves in other fields, started trying to compete as equals with NASA and its major contractors. (Musk, for example, is an Internet entrepreneur who founded PayPal.)

"SpaceX is attempting to build the same class of vehicle, to my mind, only with modern manufacturing techniques and management techniques to reduce the cost," said Jeff Greason, chief executive of XCOR Aerospace, which is building a two-seat rocket plane to take tourists to the edge of space.

Since the end of the space shuttle program, NASA has relied on Russia to take its astronauts to space in Soyuz rockets, but now it is looking to hire commercial companies for space taxi services. So there are incentives for commercial companies both to build the transportation and to offer it at competitive prices. SpaceX, for one, says that it could provide rides to NASA astronauts at $20 million a seat, a third of the Russian price.

But the new space companies are relying on taxpayer dollars to finance their research and development. The Obama administration requested $830 million for next year to finance the development of passenger-carrying spacecraft. Proponents argue that the investments will jump-start a vibrant new business that dwarfs NASA; Congress has so far remained skeptical. A report by the House committee in charge of NASA's budget said the program ran the "risk of repeating the government's experience from last year's bankruptcy of the solar energy firm Solyndra."

Despite the ambivalence on Capitol Hill, the new space competition has drawn both entrepreneurs and the old aerospace giants.

Alliant Techsystems, better known as ATK, manufactured the solid rocket boosters for the space shuttles and had the contract to build a longer-range version as the first stage for NASA's next-generation rocket, the Ares I. That was before the Ares I was canceled in favor of the space taxi approach.

ATK has now teamed up with Astrium, a European rocket company, to come up with what is essentially a commercial version of the Ares I, which it called the Liberty. Last week, ATK announced that it was developing its own capsule - based heavily on the Orion capsule that was originally going to sit on top of the Ares I - to carry astronauts for NASA one day. ATK says it, too, would charge less than the Russians.

What is not clear is whether there are people and companies interested in buying all those seats to orbit. Currently, the market for taking people into space is small. NASA needs to send only two crews a year to the space station, and if a piece of space debris were to disable the station, there would suddenly be no demand at all. The commercial future of space, while relying on NASA financing in the short run, needs new markets for manufacturers to take advantage of the economies of mass production.

"The only way to make a dramatic reduction of price is to assume a dramatic increase of launches," said Greason of XCOR. "You have to assume there is some market, that there will be enough demand to support that low price."

The current rockets - most of them good for one launching only - are very expensive regardless of whether they are built by entrepreneurs or government. The future of low-cost travel in space hinges on reusable rockets and technologies not yet developed, space experts say.

Musk declined to talk about what a profitable business model for sending people to Mars might look like, but said his ultimate goal of a $500,000 trip to Mars depended on a large number of passengers and fully reusable systems.

"I'm not going to try to convince people I can do it," he said. "I'm just going to do it."