Space Exploration Technologies (SpaceX), a private company based in Hawthorne-CA, successfully fired the second stage engines of its Falcon 9 rocket for 329 seconds (the time intended for a full duration orbit) on Saturday. The company says that its spacecraft should be ready to take to the sky in the next couple months.

Falcon 9 is part of a family of rockets that SpaceX is developing that could fill the gap in U.S. transportation to space. The space shuttles are expected to retire in 2010 and NASA’s next launch vehicle, Ares, is not scheduled to be ready for flight until 2015.

SpaceX initially started developing its rockets for space tourism and for launching scientific and commercial satellites into orbit, and has successfully flown a previous rocket, Falcon 1. Last year, the company won a $1.6 billion contract through NASA’s Commercial Orbital Transportation Services (COTS) program to provide the space agency with a vehicle capable of reaching the International Space Station. Commercial launch vehicles could also help reduce spaceflight costs for the U.S. government. Aboard Falcon 9 will be the company’s Dragon capsule, a spacecraft designed to carry both cargo and crew.

The maiden flight of Falcon 9 has been hit with delays–last fall the company was promising to launch the rocket by the end of 2009 after they conducted successful first stage engine firings. But the company says it will be shipping the second stage to Cape Canaveral, FL (the launch site) by the end of the month and, “depending on how well full vehicle integration goes, launch should occur one to three months later.”