Federal officials hold public hearing to determine probable cause of spaceship crash

The National Transportation Safety Board is meeting to try to determine what likely caused a Virgin Galactic spaceship to break apart over the Mojave Desert during a test flight 10 months ago, killing the co-pilot and seriously injuring the pilot.

Investigators have been looking into pilot training, the rocket's design and whether mechanical problems played any role.

NTSB officials said early in the investigation that the co-pilot prematurely unlocked equipment designed to slow the descent of the spacecraft. Simply unlocking the spacecraft's brakes shouldn't have applied them, but investigators say that might have happened anyway, putting stress on the spacecraft.

Virgin Galactic is building another spacecraft as it proceeds with its plans for space flight. Eventually, it envisions flights with six passengers climbing more than 62 miles above Earth.