The builder of SpaceShipTwo had not considered that human error could result in a catastrophic hazard to the space vehicle, the National Transportation Safety Board said Tuesday in determining the cause of last year’s crash in the Mojave Desert.

The board, meeting in Washington, D.C., placed blame for the Oct. 31 crash, which killed a co-pilot, on Scaled Composites, the company based at the Mojave Air & Space Port that built SpaceShipTwo for commercial space operator Virgin Galactic.

Scaled, a subsidiary of aerospace giant Northrop Grumman Corp., had not ensured that test pilots were aware of the dangers of unlocking early a descent mechanism, known as the feather system, attached to the space vehicle’s tail. Nor had the company used technology to protect against human error by the pilots flying the vehicle.

The feather system was to be deployed at a speed of 1.4 Mach but instead was done at 0.8 Mach. The report indicated there were no structural, system, or rocket motor failures before the in-flight breakup.

Virgin Galactic is developing SpaceShipTwo to take passengers up to an altitude of 62 miles above Earth. About 700 people had signed up to fly on the six-passenger craft, which would originate its flights from New Mexico. Tickets cost roughly $250,000.

SpaceShipTwo crashed minutes into an October test flight, killing co-pilot Michael Alsbury, 39, and injuring pilot Peter Siebold, 43, who parachuted to safety.

A second SpaceShipTwo vehicle was already being built at the time of the crash at Spaceship Co., a Virgin Galactic subsidiary also based at the Mojave Air & Space Port.