SpaceX Is Set to Send Its Rocket to the Space Station In space, how quickly does grape juice turn to wine? Two California high school students hope to find out soon. Their experiment is one of 11 aboard a rocket scheduled to blast off early Saturday from Cape Canaveral, Fla., to the International Space Station. "We think it's going to ferment faster," said Max Holden, a ninth grader at Chaminade College Preparatory in West Hills, Calif. But there is no guarantee that the seven-inch tube of yeast and grape juice will ever reach its destination. The launching is a test flight of a spacecraft built by the Space Exploration Technologies Corporation, or SpaceX, of Hawthorne, Calif. The event is slightly historic: if all goes well, the ship will be the first operated by a private company, rather than the government, to supply the space station. Erring on the side of caution, officials at NASA and SpaceX have stressed that the purpose of the mission is to shake out glitches. "I think there's a significant chance the mission does not succeed," said Elon Musk, chief executive of SpaceX. The craft, a Falcon 9 rocket with a Dragon capsule on top of it, will carry more than 1,000 pounds of cargo, mostly food and clothing - items that NASA regards as no big loss should the launching fail. The only scientific experiments on the mission are those devised by students as part of a program run by the National Center for Earth and Space Science Education. They will explore the effects of zero gravity, including whether medicines can slow bone loss and whether certain bacteria that eat plastic would thrive and eat greater amounts of plastic in space. The liftoff, set for 4:55 Saturday morning, is timed to take place at the moment the launching pad lines up with the space station's orbit. If weather or a technical problem keeps the rocket on the ground, SpaceX will have to wait until 3:44 a.m. Tuesday for the pad and orbit to line up again. After reaching orbit, the Dragon capsule is to perform a series of test maneuvers. On the third day, it is scheduled to fly 1.5 miles under the space station to demonstrate its navigation and communication systems. If it passes the tests, NASA will give the go-ahead for the final approach on Tuesday, when Donald R. Pettit, a NASA astronaut, will use the space station's robotic arm to grab the Dragon and pull it to a docking port. If successful, the Dragon would be the first commercial spacecraft to visit the space station, and SpaceX would collect the remaining payments on a $396 million agreement with NASA to develop the cargo ship. SpaceX would then enter a $1.6 billion contract for a dozen cargo flights to the station. If the flight fails, SpaceX would have to repeat the demonstration flight until it succeeds. SpaceX has so far avoided the early failures that typically accompany a new rocket like the Falcon 9. The maiden flight, in June 2010, was almost flawless. The second flight - the first under the NASA agreement - was in December 2010, putting into orbit a Dragon capsule that successfully parachuted back to Earth. The successes have, however, taken longer than anticipated. SpaceX originally predicted its first visit to the space station would be in 2009. The delays were not a big surprise, Mr. Musk said, given the complexities. "Certainly, we would have hoped to have been further ahead," he said, "but I wouldn't have expected that with great confidence." For the students at Chaminade Preparatory looking forward to the winemaking experiment, the launching will be particularly exciting. If the capsule makes it to the space station, one of the astronauts there will mix the grape juice and yeast and let it ferment for five days. Max Holden and his lab partner, Paige D'Andrea, a 10th grader, will perform the same experiment, and when the space wine is returned to Earth about a month later, they will compare the two. "When we get it back, we're going to get one of the priests to bless it," said Nancy McIntyre, the director of the project for Chaminade, a Catholic school. To figure out which one is more alcoholic, the students will not taste any of the fermented grape juice, but instead will measure the amount of carbon dioxide produced by the yeast.