It was to have been the dawn of a new era, private companies launching into space and on to the International Space Station.
The first such launch was set for before dawn this morning, and it came tantalizingly close.
But the SpaceX rocket never got off the ground.
The launch was aborted just half a second before liftoff.
It was so close, that even NASA announcer George Diller was caught by surprise.
"Three, two, one, zero and liftoff," said Diller. Then he realized the rocket was still on the pad, "We've had a cutoff. Liftoff did not occur." SpaceX President Gwynne Shotwell blamed high combustion pressure in engine no. 5, one of nine engines needed for liftoff.
Onboard computers detected the problem, and shut everything down.
Shotwell said engineers will now being trouble shooting to find and fix the problem, and switch out the engine if necessary.
The next possible launch date is next Tuesday, May 22.
Despite the disappointment of today's near-launch, Shotwell insisted, "This is not a failure. We aborted with purpose", she said, "It would be a failure if we were to have lifted off with an engine trending in this direction."
SpaceX is one of a handful of private companies racing to get into space, hoping to send cargo and eventually astronauts to the space station for NASA.
With the space shuttles parked in museums and NASA relying on the Russians for space transportation, the agency is looking to private companies to fill in the gap.
NASA Administrator Charles Bolden told ABC News, these commercial companies are "now going to be primarily responsible for building and operating, and we're going to buy the service from them or purchase the service from them."
NASA has shelled out $396 million to SpaceX for test flights, like this mission. It also has a $1.6 billion contract with the company for 12 cargo flights to the space station.
SpaceX is the dream of billionaire Elon Musk, who made his fortune creating PayPal.
He began his space efforts a decade ago.
Before the launch he was both realistic and optimistic.
Musk told ABC News, "I think we are more likely than not going to succeed in this mission but it is a test flight. And there is certainly any number of things that could go wrong. And so we may not actually. We have 2 more flights for later this year. So I'm confident that one of those flights will make it."
The Associated Press contributed to this report.