An unmanned US supply rocket exploded shortly after lifting off from a commercial launch pad in Virginia, the first disaster since Nasa turned to private operators to run cargo to the International Space Station.

The 14-story Antares rocket, built and launched by Orbital Sciences Corp, blasted off from the Wallops Flight Facility at 2222 GMT on Tuesday but burst into flames moments later and plunged back to the ground in a massive ball of fire and smoke.

No one was hurt in the crash, authorities said. The craft was carrying a Cygnus cargo ship bound for the station, a $100 billion research laboratory owned and operated by 15 nations that orbits about 418 km above Earth.

Accident renews questions about the use of Russian engines in US rockets

Another resupply vehicle, the unmanned Russian Progress spacecraft, successfully launched from the Baikonur Cosmodrome in Kazakhstan just hours later with nearly three tons of food, fuel and supplies.

The loss of the Cygnus supply vessel posed no immediate problem for the orbiting team of six crew members – two Nasa astronauts, one from the European Space Agency and three Russian cosmonauts – officials said.

The unmanned Antares rocket exploding seconds after lift off. The 14-story rocket burst into flames and plunged to the ground in a huge ball of fire and smoke. Photo: Reuters/Matthew Travis/Zero-G News

“There was no cargo that was absolutely critical to us that was lost on that flight. The crew is in no danger,” Nasa associate administrator William Gerstenmaier said.

The cause of the mishap was under investigation, said Frank Culbertson, Orbital Sciences executive vice president.

Russia’s Roskomos space agency said it was ready to help ferry extra US cargo to the International Space Station if Nasa requested such assistance. Cygnus had been due to loiter in orbit until November 2, then fly to the station so astronauts could use a robotic crane to snare the capsule and attach it to a berthing port.

The station is overseen by Russia and the United States, whose relations are at a low ebb over the Ukraine crisis.

Footage of Tuesday’s launch showed the Antares rising slowly into the night sky as flames suddenly engulfed the rocket, about 11 seconds after liftoff, before the vehicle sank back downward.

Ronda Miller, manager of the Ocean Deli in Wallops Island, Virginia, told Reuters she felt the force of the blast from the eatery, about eight kilometres from the launch pad.

“We were standing outside waiting for it to launch and we saw bright red, and then we saw a big black cloud, and it shook the whole building where we work,” Miller said.

The Orbital Sciences Corporation Antares rocket, with the Cygnus spacecraft onboard, arrives at launch Pad-0A at Nasa’s Wallops Flight Facility in Virginia last Friday. Photo: Reuters

The Cygnus mission was non-military, but the company’s Antares programme manager, Mike Pinkston, said the craft included “some classified cryptographic equipment, so we do need to maintain the area around the debris in a secure manner”.

The accident renewed questions about the use of Russian engines in US rockets.

The Antares is powered by the AJ-26 engine built by GenCorp Inc division Aerojet Rocketdyne. In May, an AJ-26 exploded during a ground test at Nasa’s Stennis Space Center in Mississippi.

Orbital Sciences and Aerojet have not yet released the cause of that engine failure.

Congress has been more concerned about Russian-made RD-180 engines that power United Launch Alliance’s Atlas 5 rockets, used primarily to fly US mili-tary satellites.

The RD-180 has had notechnical problems, but Russia has threatened to sus-pend exports in response to US trade sanctions prompted by Moscow’s annexation of Ukraine’s Crimea region.

United Launch Alliance is a partnership of Lockheed Martin and Boeing.