VIDEO: NTSB news conference on start of SpaceShipTwo investigation

Investigators have plenty of evidence to sift through as they look into the cause of the fatal crash of a Virgin Galactic rocket plane, but the acting chair of the National Transportation Safety Board said the inquiry may take up to a year to complete.

Just 13 seconds after Virgin Galactic’s SpaceShipTwo began a rocket-powered test flight — and just five seconds after its innovative aero-braking system was inadvertently deployed at supersonic speeds — the spaceplane apparently broke up, killing one pilot and injuring another, according to a National Transportation Safety Board timeline.

Four-and-a-half years after an initial sub-orbital test flight, Richard Branson’s Virgin Galactic is finally ready to begin commercial operations with the launch Thursday of a six-man crew, including three Italian researchers, on an up-and-down flight to the edge of space aboard the company’s winged spaceplane.