Officials beginning the investigation of the crash of Virgin Galactic's SpaceShipTwo (SS2) prototype spaceplane say the wreckage is spread over five miles of the Mojave desert, giving a clear indication that the vehicle broke up in midair.

Describing the initial results of the first day of the investigation, acting NTSB chairman Christopher Hart says the debris field extends from north-east to south-west, and follows the trajectory of SS2 when it was released from the WhiteKnightTwo carrier aircraft for its ill-fated test flight on Oct. 31.

The first sections to fall to earth were the vehicle's two moveable tail-booms, followed by the main fuselage and wing section. The fuselage contained the remains of the large nitrous oxide oxidizer tank, Hart says. "Next [to fall] was the cockpit and the engine itself."

The investigation team has been split into groups to cover the vehicle, systems, engine, vehicle performance, data and operations. "The engine group has looked at the fuselage with the oxidizer and methane tanks … They have not yet looked at the engine itself," Hart says. The methane is used in addition to the nitrous gas and is used to help with the combustion of the plastic-based fuel grain which was being flight-tested for the first time in the hybrid rocket motor.

Hart says the surviving pilot, Scaled Composite's test pilot Peter Siebold, is still too unwell to be interviewed about the accident. Earlier, however, Virgin Galactic confirmed that Siebold, who is the director of flight operations at Scaled Composites, was "alert and talking with his family and doctors." Hart adds that "we do not know how the pilot got out of the aircraft." The other pilot, Michael Alsbury, died in the accident.

The NTSB investigation, which will wrap up its onsite inspections and data collection within 4-7 days, is able to access a wealth of data. This includes footage from six cameras on SS2, three on the carrier aircraft, cameras on the chase aircraft, a long-range camera from nearby Edwards AFB, and radar data. The aircraft was also transmitting data to the ground with around 1,000 parameters contained in the telemetry stream.