LOS ANGELES -- The first mission by a private company to the International Space Station was aborted before dawn Saturday at Cape Canaveral, Fla., when computers detected an anomaly in one of the rocket's engines and automatically shut down the launch sequence.
The countdown for Space Exploration Technologies Corp., or SpaceX, was flawless until about 4:55 a.m. EDT when, at the last second, the rocket engines briefly lit up and then went dark.
"Three, two, one, zero and liftoff," NASA commentator George Diller announced before he realized what had happened. "We've had a cutoff. Liftoff did not occur."
As thousands watched for the pre-dawn launch and heard the countdown reach zero, nothing happened.
"I was looking for the first motion, which I thought I saw. But it cut off at a half a second," Diller said later. "I thought it was out of here. But the first motion sensors indicated it had not moved."
In a news conference shortly afterward, SpaceX President Gwynne Shotwell said company computers detected high combustion chamber pressure on one of the Falcon 9 rocket's nine engines, which caused the shutdown.
"We need all nine to lift off, which is why we aborted," she said. "This is not a failure. We aborted on purpose."
Shotwell said SpaceX engineers and technicians would work to address the issue in the coming days.
The next window for the company to launch to the space station is at 3:44 a.m. Tuesday. SpaceX also has an opening at 3:22 a.m. Wednesday.
SpaceX's Falcon 9 rocket could be rolled back into the hangar for inspection and repairs, including possible disassembly. In fact, SpaceX has a second Falcon 9 rocket at Kennedy Space Center and could swap the engine 5s if necessary.
Shotwell said there is a chance even that could be done before Tuesday.
This would have been the third launch of the Falcon 9 rocket. The first two also were aborted on the first try.
The company, based in Hawthorne, Calif., is launching the rocket carrying its Dragon space capsule in a demonstration for NASA.
The unmanned docking mission to the space station is intended to prove that SpaceX's rocket and capsule are ready to haul cargo for the space agency now that the space shuttle fleet has been retired.
NASA has begun hiring privately funded startup companies for spacecraft development and is moving toward eventually outsourcing NASA space missions.
SpaceX has a $1.6 billion contract to haul cargo in 12 flights to the space station.
Even though the upcoming mission is a test flight, the Dragon capsule is carrying about half a ton of food and other supplies.
The capsule is supposed to dock with the space station three days after launch. If the mission is successful, it will mark the first time that a privately built craft has docked with the station.
In December 2010, SpaceX became the first private company to send a spacecraft into orbit and return it intact. The company employs about 1,800 people.