The builder of SpaceShipTwo had not considered 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 that 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. “This failure set the stage for the copilot’s premature unlocking of the feather system as a result of time pressure and vibration and loads that he had not recently experienced, which led to uncommanded feather extension and the subsequent aerodynamic overload and in-flight breakup of the vehicle,” the board said in its report. 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 last October minutes into a test flight, scattering pieces for miles in empty Mojave Desert scrub just east of Red Rock Canyon Park. Copilot Michael Alsbury, 39, was killed in the crash while pilot Peter Siebold, 43, parachuted to safety but was injured. 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.