A rocket developed by internet entrepreneur Elon Musk's Space Exploration Technologies has lifted off and reached orbit.
Nasa is hoping the test flight will eventually lead to cargo runs to the International Space Station after its space shuttles are retired next year.
The Nasa-backed mission is also intended to test a new capsule system aimed at eventually delivering a crew to the ISS.
Space Exploration Technologies' Falcon 9 rocket lifted off from Cape Canaveral Air Force Station, carrying the company's first Dragon capsule.
Two more test flights are planned, though the company may decide to combine its remaining test flights and make a docking at the space station next summer.
The California-based firm, created by the co-founder of PayPal, is one of two companies holding a combined $3.5 billion in Nasa contracts to deliver cargo to the space station after the space shuttles are retired.
Nasa is also contributing a combined $500 million for SpaceX and Orbital Sciences to develop and test-fly their rockets and capsules.
SpaceX intends to begin station deliveries by the end of 2011, with Elon Musk saying he could be launching station crews within three years of getting the go-ahead from Nasa.