SpaceX lift-off: first commercial cargo ship successfully blasts into space In more good news, a piece of space junk was no longer threatening the station, and Nasa could focus entirely on the delivery mission. Nasa is counting on private business to restock the space station, now that the shuttles have retired to museums. The space agency has a $1.6 billion contract with SpaceX for 12 resupply missions. Especially exciting for Nasa is the fact that the Dragon will return twice as much cargo as it took up, including a stockpile of astronauts' blood and urine samples. The samples - nearly 500 of them - have been stashed in freezers since Atlantis made the last shuttle flight in July 2011. The Dragon will spend close to three weeks at the space station before being released and parachuting into the Pacific at the end of October. By then, the space station should be back up to a full crew of six. None of the Russian, European or Japanese cargo ships can bring anything back; they're destroyed during re-entry. The Russian Soyuz crew capsules have limited room for anything besides people. Space Exploration Technologies Corp., or SpaceX - owned by PayPal co-founder Musk - is working to convert its unmanned Dragon capsules into vessels that could carry astronauts to the space station in three years. Other US companies also are vying to carry crews. Americans must ride Russian rockets to orbit in the meantime, for a steep price. Musk, who monitored the launch from SpaceX Mission Control in Hawthorne, California, called the capsules Dragon after the magical Puff to get back at critics who, a decade ago, considered his effort a fantasy. The name Falcon comes from the Millennium Falcon starship of "Star Wars" fame. An estimated 2,400 guests jammed the launching centre to see the Falcon, with its Dragon, come to life for SpaceX's first official, operational supply mission. Across the country at SpaceX headquarters, about 1,000 employees watched via TV and webcast. It was no apparition. "Just over a year after the retirement of the space shuttle, we have returned space station cargo resupply missions to US soil," said Nasa Administrator Charles Bolden junior SpaceX is shooting for its next supply run in January. Another company looking to haul space station cargo, Virginia's Orbital Sciences Corp., hopes to launch a solo test flight in December and a demo mission to the station early next year. Every time SpaceX or a competitor flies successfully, Bolden told reporters, "that gives the non-believers one more opportunity to get on board and root for us" and help enable commercial launches for space station astronauts. This will further free NASA up to aim for points beyond low-Earth orbit, like Mars. "This was a big night," Bolden concluded.