The launch of an unmanned SpaceX rocket automatically shut down at the last second early Saturday morning, pushing back the first cargo run by a privately built spacecraft to the International Space Station to Tuesday at the earliest.
The SpaceX Falcon 9 booster carrying a Dragon capsule laden with supplies for the ISS had actually started firing up on a Cape Canaveral launch pad at the three-second mark of the countdown. But the spacecraft's onboard computers shut down due to "slightly high combustion chamber pressure on engine No. 5," SpaceX co-founder Elon Musk said on Twitter after the launch was aborted at around 4:55 a.m. ET. "Will adjust limits for countdown in a few days."
A SpaceX spokesperson said Saturday that "[d]ue to the instantaneous launch window, we are not able to recycle and re-attempt the launch today." She reiterated Musk's statement about the issue with engine No. 5, but noted that SpaceX and NASA are still reviewing the data to determine what went wrong.
NASA and SpaceX were scheduled to hold a briefing on the aborted launch at 6:30 a.m. Eastern.
All appeared to be going well until the rocket engines cut off, leaving the spacecraft on the launch pad at Launch Complex 40 at the Cape Canaveral Air Force Station "amid a plume of engine exhaust," according the Associated Press.
The Dragon's computer systems have checked out following a longer-than-expected software validation process that delayed the mission's earlier May 7 launch date. Other technical issues that have caused months of delays to the first commercial flight to the ISS were also resolved.
But SpaceX president Gwynne Shotwell told reporters Friday that SpaceX has never managed a liftoff of a Falcon 9 on the very first try. In fact, SpaceX has only launched its current booster rocket once before, on a December 2010 test flight that carried a Dragon capsule into orbit and back again as part of NASA's Commercial Orbital Transportation Services (COTS) program.
SpaceX and NASA are calling the mission to the ISS a test flight as well. The goal of the mission is to ferry 1,150 pounds of cargo aboard the SpaceX Dragon for delivery to the ISS and then take on a 1,455-pound payload to bring back to Earth.
But first, SpaceX has to insert its Dragon spacecraft into orbit, which it failed to do Saturday. Once in space, the capsule will take approximately 75 hours to reach the space station and, if it passes a system check, dock with the ISS and unload supplies for the astronauts aboard.
Had Saturday's liftoff occurred, the ISS rendezvous would have happened sometime on Tuesday.
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