For the first time, a private company will launch a rocket to the International Space Station, sending it on a grocery run this weekend that could be the shape of things to come for America's space program.
If this unmanned flight and others like it succeed, commercial spacecraft could be ferrying astronauts to the orbiting outpost within five years.
It's a transition that has been in the works since the middle of the last decade, when President George W. Bush decided to retire the space shuttle and devote more of NASA's energies to venturing deeper into space.
Saturday's flight by Space Exploration Technologies Corp. is "a thoroughly exciting moment in the history of spaceflight, but is just the beginning of a new way of doing business for NASA," said President Obama's chief science adviser, John Holdren.
By handing off space station launches to private business, "NASA is freeing itself up to focus on exploring beyond low Earth orbit for the first time in 40 years."
California-based Space Exploration, or SpaceX, is the first of several companies hoping to take over the space station delivery business for the United States. The company's billionaire mastermind, Elon Musk, puts the odds of success in his favor while acknowledging the chance for mishaps.
NASA likewise cautions: This is only a test.
"We need to be careful not to assume that the success or failure of commercial spaceflight is going to hang in the balance of this single flight," said Mike Suffredini, NASA's space station program manager. "Demo flights don't always go as planned."
Saturday's launch is set for 4:55 a.m. EDT.
Once it nears the space station after a two-day flight, the SpaceX capsule, called Dragon, will spend a day of practice maneuvers before NASA signals it to move in for a linkup. Then its cargo -- a half-ton of food and other pantry items, all non-essential, in case the flight goes awry -- will be unloaded.
Up to now, flights to the space station have always been a government-only affair.
Until their retirement last summer, shuttles carried most of the gear and many of the astronauts to the orbiting outpost. Since then, American astronauts have had to rely on Russian capsules for rides. European, Japanese and Russian supply ships have been delivering cargo.
It will be at least four to five years before SpaceX or any other private operator is capable of flying astronauts. That gap infuriates many. Some members of Congress want to cut government funding to the private space venture and reduce the number of rival companies to save money and speed things up.
No one is rooting more for SpaceX than NASA. The space agency has poured $381 million into the SpaceX effort, while the company has spent $1 billion over its 10-year lifetime, said Musk, the high-tech pioneer who co-founded PayPal and Tesla Motors, the electric car company.
The Dragon will be cut loose from the space station about two weeks after arriving and aim for a Pacific splashdown off the California coast.
Other U.S. companies vying for a shot at launching space station astronauts -- like Sierra Nevada Corp., which is designing the mini-shuttle Dream Chaser -- are cheering onSpaceX since it is the first one out of NASA's post-shuttle, commercial gate.