An unmanned, privately owned Falcon 9 rocket and Dragon cargo capsule has blasted off from Cape Canaveral on a mission to restore a US supply line to the International Space Station after the retirement of the space shuttle.
Powered by nine oxygen and kerosene-burning engines, the 157-foot (48-metre) tall rocket, built by Space Exploration Technologies, lifted off from its seaside launch pad at Cape Canaveral Air Force Station at 8:35pm (0035 GMT on Monday).
The Falcon booster, flying for the fourth time, streaked through balmy, partly cloudy skies as it headed east over the Atlantic Ocean toward the station's orbit, some 250 miles (400 km) above Earth.
If all goes as planned, the capsule will reach the $100 billion space station, a project of 15 nations, on Wednesday.
The company, also known as SpaceX, made a successful practice run to the station in May, clearing the way for it to begin working off a $1.6 billion, 12-flight contract to deliver cargo for Nasa.
The Dragon cargo capsule carries about 882 pounds (400kg) of food, clothing, science experiments and supplies for the station. The gear includes a freezer to transport medical samples, and a rare treat for the station crew - chocolate vanilla swirl ice cream.
With the retirement of the space shuttles last year, Nasa turned to the private sector to develop and fly station freight and is looking to do the same for crew transportation.
"We're thrilled that we are again launching to the space station from Florida," Nasa deputy administrator Lori Garver said shortly before the launch.
Unlike the Russian, European and Japanese freighters that service the station, Dragon is designed to return to Earth intact, rather than burn up in the atmosphere, so it can bring back research and equipment from the station.
That return capability has been missing since the shuttle's retirement.
Dragon is scheduled to depart the station on 28 October and to splash down into the Pacific Ocean off the coast of California.
In addition to SpaceX, Nasa has also hired Orbital Sciences Corp to fly cargo to the station. Orbital's Antares rocket is expected to make a debut flight later this year.