The maiden launch of the Falcon 9 rocket could still take place this winter, according to Space Exploration Technologies (SpaceX) Chief Executive Elon Musk, who posted details of the medium-lift rocket’s recent second-stage test firing and updated launch schedule to the Hawthorne, Calif.-based company’s Web site Jan. 4.

“This was the final stage firing required for launch, so the second stage will soon be packaged for shipment and should arrive at Cape Canaveral by end of month,” Musk stated on the Web site. “Depending on how well full vehicle integration goes, launch should occur one to three months later.”

Falcon 9’s debut was planned for 2007 but development of the rocket has taken longer than SpaceX anticipated.

SpaceX said last fall that the inaugural Falcon 9 launch — a demonstration flight for an unnamed customer — would carry a qualification version of the Dragon cargo capsule SpaceX is building with NASA financial assistance.

SpaceX officials have said the flight is not intended to count as one of the three Dragon flight demos the company is obliged to fly for NASA under a $278 million Commercial Orbital Transportation Services (COTS) agreement signed in 2006. That agreement called for SpaceX to fly its first COTS demo in September 2008, a second in June 2009 and a third in September 2009. NASA and SpaceX agreed upon a revised schedule in February 2008 that shifted the first COTS demo to June 2009, followed by a second in November 2009 and the third in March 2010.

SpaceX issued a press release in early December indicating it aims to launch Dragon to the international space station sometime between May and November.