Feathering

Preliminary conclusions in the investigation into the SpaceShipTwo accident are that the mechanism that allows the craft to glide back to Earth--- the so-called feathering mechanism-- engaged prematurely, causing the craft to break up.  In that case, the new fuel used on the flight would not have been a factor in the tragedy.

Sir Richard Branson, owner of Virgin Galactic, says the company's efforts will continue.