An unmanned Orbital Sciences Corp. Antares rocket was launched on Thursday to deliver cargo to the International Space Station for NASA.
Lift-off from the Wallops base in Virginia was at 1.07pm local time and orbit was achieved 10 minutes later.
The Cygnus freighter is scheduled to rendezvous with the station early on Sunday.
The BBC reports it is ferrying just over 1.2 tonnes of supplies to the ISS, including food, clothing, spare parts and scientific experiments.
The launch, which was broadcast live on NASA Television, was delayed twice this week, first by cold weather and then by high space radiation due to a massive solar flare on Tuesday.
Orbital Sciences is one of two companies hired by the National Aeronautics and Space Administration to fly cargo to the station, since the retirement of the space shuttles in 2011.
Space Exploration Technologies is the other. SpaceX is preparing for its third supply run on 22 February from Cape Canaveral in Florida.
OSC has a $US1.9 billion contract with NASA to fly eight cargo ships to the station, an international research outpost about 400km above Earth.
SpaceX has a separate NASA contract worth $1.6 billion for 12 flights.