The SpaceX-operated Falcon 9 rocket carrying the Dragon cargo vehicle bound for the International Space Station exploded shortly after lift-off from Cape Canaveral Air Force Station on Sunday.
The explosion took place only two minutes into the flight with no obvious cause, just as the spacecraft was about to separate from its first stage. Shortly after the accident, SpaceX’s CEO Elon Musk tweeted that ‘there was an overpressure event in the upper stage liquid oxygen tank’.
Later, he added that the exact cause was still unknown, despite 'several thousand of engineering hours of review'.
The incident marks the third loss of an ISS resupply vehicle in about eight months. In October this year, SpaceX’s US rival Orbital Sciences lost its Antares rocket with a Cygnus cargo carrier aboard in a fireball launch-pad explosion.
In fact, the ill-fated Dragon flight was the first ISS-bound resupply mission since the loss of Russia’s Progress carrier that was left tumbling in the Earth’s orbit due to a failure during separation from the Soyuz rocket.
The lost Dragon capsule carried some 2,500kg of food, clothes and equipment, including a new docking system that was supposed to be installed at the station ahead of the planned arrival of Nasa’s new private space taxis.
"This was a blow to us,” Bill Gerstenmaier, Nasa Associate Administrator told a news conference after the disaster. “We lost a lot of research equipment on this flight."
Dragon, the first private space freighter which started operating in summer 2012, has already conducted 15 successful missions under a Nasa contract.
The firm is one of two developers building a space capsule for astronauts under a Nasa contract. In addition to the manned Dragon, Boeing is developing its Crew Transportation System CST-100.
The incident won’t immediately affect the ISS crew, which still has approximately four months’ worth of food aboard, Nasa said. There are currently only three astronauts aboard the ISS; one American and two Russians, half of the full operational count of six.
The station is expected to be back to six crew members in July. However, if food or water supplies dwindled to 45 days, some of the crew could return home via the Russian Soyuz capsules that are parked at the outpost.
SpaceX was expected to attempt a controlled landing of Falcon 9’s first stage during the ill-fated flight – an experiment that has failed twice previously.
The accident will ground Falcon 9 for several months, although SpaceX President Gwynne Shotwell expressed confidence that the grounding will last ‘less than a year’.
As the Orbital Sciences vehicle hasn't returned to flight since its October mishap, the US will now be dependent on Russia and Japan to resupply the station.
Russia hopes to return its troubled Soyuz rocket and Progress cargo ship to flight on Friday. Japan is slated to fly its HTV capsule to the station in August.
The incident may affect SpaceX’s chances in a competition for a contract to launch US surveillance and military satellites, which is currently served solely by a joint venture between Lockheed Martin and Boeing, the United Launch Alliance.
Including its station cargo runs for Nasa, SpaceX has a backlog of nearly 50 missions - worth more than $7bn - including dozens of commercial communications satellites.