The countdown reached all the way to practically zero Saturday morning for the SpaceX Falcon 9 rocket. A NASA spokesman said the engine ignition sequence started, but there was an automatic shutdown by on-board computers. So instead of blasting off fromCape Canaveral on a delivery mission to the International Space Station, the rocket remained on its launch pad amid a cloud of engine exhaust.

An engine pressure problem is suspected. The next launch attempt will be Tuesday, if the problem can be resolved in time.

This was the first launch attempt by one of the private U.S. companies hoping to take over the job of delivering cargo and eventually astronauts to the space station for NASA. AP