An unmanned cargo ship packed with 7,400 pounds (3,350 kilograms) of food and supplies for the astronauts living at the International Space Station blasted off Sunday from Wallops Island, Virginia.

Orbital ATK's barrel-shaped Cygnus cargo ship launched atop an Antares rocket at 7:19 am (1219 GMT), a day after a last-second delay due to an unexpected aircraft in the area.

"Five, four, three, two, one and we have ignition," said Orbital ATK's mission control operator, as the rocket's engines lit up the chilly, gray morning and cheers erupted from spectators near the launch site.

The spacecraft reached orbit about nine minutes later.

NASA commentator Rob Navias described the launch as "flawless."

The mission is the eighth for Orbital ATK, which has a $1.9 billion contract with NASA to resupply the orbiting outpost.

SpaceX also has a $1.6 billion contract with NASA, sending its Dragon cargo ship to regularly re-stock the space lab.

Among the experiments on board is a satellite that will test how bacteria grows in microgravity, and determine the minimum amount of antibiotic needed to stop its growth.

Knowing how bugs will act during long-duration missions will help the US space agency, which hopes to send people to deep space in the coming decades, with a human mission to Mars sometime in the 2030s.

Cygnus is scheduled to arrive at the orbiting outpost on Tuesday.

Italian astronaut Paolo Nespoli of the European Space Agency and NASA astronaut Randy Bresnik will use the space station's robotic arm to grab Cygnus at about 4:50 am (0950 GMT), NASA said.

Astronauts will unload its contents, then repack it with several tons of trash so it can be shipped off on December 4.

Eventually, it will burn up upon re-entry into Earth's atmosphere.

The current crew of six astronauts on duty at the space station include three Americans, one Italian and two Russians.

Source:AFP