CAPE CANAVERAL: A last-minute problem halted Saturday's launch countdown for Boeing's first astronaut flight.
Two NASA astronauts were strapped into the company's Starliner capsule and awaiting liftoff when the countdown was halted at three minutes and 50 seconds.
With only a split second to take off Saturday afternoon, there was no time to work the latest trouble and everything was called off.
The launch was previously delayed for leak checks and rocket repairs.
NASA wants a backup to SpaceX, which has been flying astronauts for four years.