The unmanned rocket along with its cargo spacecraft, which was headed for the ISS, exploded during a launch on Tuesday evening from NASA's Wallops Flight Facility in Virginia.

Built and launched by contracted company Orbital Sciences Corps., the CRS-3 mission rocket appeared to lift just above its own height from the launch pad and exploded seconds after blastoff at 6:22 p.m. (22:22 UTC).



The cause was not immediately available and there were no initial reports of injuries, with everyone thought to be at the launch site accounted for.

NASA tweeted that it and contractor Orbital Sciences Corps were gathering data on the failure of the rocket to launch. Moments after the accident, a mission controller was said to have instructed launch workers to "secure the facility and collect all data."

The unmanned Cygnus cargo spacecraft that the rocket was carrying had some 2,200 kilograms (5,000 lbs) of food, as well as materials for experiments on board.

Virginia-based Orbital Sciences is one of two private companies that NASA has hired to take cargo to the space station. The flight on Tuesday was to have been the third out of eight, under a $1.9 billion contract between the firm and NASA.

A separate supply line to the station is run by privately owned Space Exploration Technologies, or SpaceX, which is preparing for a fourth flight as part of a separate, $1.6 billion contract.

With a Russian cargo ship set to reach the space station on Wednesday in any case, the loss of the Cygnus supply vessel was expected to pose no immediate problem for the orbiting ISS team.

rc/gsw (Reuters, dpa, AFP)