LOS ANGELES—Virgin Galactic’s SpaceShipTwo (SS2) crashed in Mojave Desert after experiencing an in-flight "anomaly" during the first test of a new hybrid rocket motor at Mojave, California, on Oct 31.

Reports so far indicate one of the two test pilots on board survived after bailing out of the suborbital spacecraft, which was making its fourth powered flight. The other pilot did not survive the crash.

The flight, which marked the first time the vehicle had flown under its own power since January, was to have been a key step on the way to completing flight tests of the space vehicle before the planned transfer to Virgin Galactic for the build-up to initial customer flights in 2015.

The problem appears to have developed several minutes after ignition of the rocket following release from the WhiteKnightTwo carrier aircraft, which departed Mojave at 9:19 am Pacific. The flight was testing the performance of the new polyamide-based grain that was adopted in place of the hydroxyl-terminated polybutadiene, a form of rubber that was used for the first series of powered tests. Scaled and Virgin, which announced the decision to change to the new fuel in May, made the switch in hopes of providing a longer, more energetic burn with lower thrust oscillations.