SpaceX, based in California, has successfully flown two rockets, the Falcon 1 and Falcon 9, and has a NASA contract to deliver cargo to the International Space Station with the Falcon 9 and the company's Dragon space capsule.
The new rocket, dubbed Falcon Heavy, was announced by SpaceX head Elon Musk in Washington, a company release said.
The Falcon Heavy will take 53 tons into Earth orbit, more than any other rocket currently being launched, NewScientist.com reported Wednesday.
"This opens a new world of capability for both government and commercial space missions," Musk said.
The company says it plans an inaugural test launch of the Falcon in 2013 or 2014.