There are still months of investigating left to be done on SpaceShipTwo's tragic crash in the Mojave desert Friday. But after the National Transportation Safety Board held the last of four Mojave-based press conferences on the investigation Monday night, we're a lot closer to figuring out the cause.
Immediately after the crash, speculation surrounded the new polymer-based fuel the ship had been using in the air for the first time. That's almost certainly not the culprit, NTSB acting chairman Christopher Hart suggested, since the fuel tank was found relatively intact.
Instead, the Feds are already pointing the finger at the craft's "feathers" -- that is, the back part of the wings that were supposed to deploy to slow the craft down after it reached its appointed speed. The feathers deployed early, apparently at just the wrong moment -- Mach 1.0, rather than the intended Mach 1.4. SpaceShipTwo exploded two seconds after that.
Now it's the NTSB's job to figure out why the feathers were deployed.
The agency confirmed Monday night that the feathers had a two-part unlocking system. The first part was unlocked by the co-pilot, Michael Alsbury, who died in the crash. It isn't know why Alsbury did that, and it also isn't known how the second part unlocked, but Hart believes neither pilot took that second step.
Pete Siebold, the pilot, parachuted from the craft just in time. He was hospitalized for his injuries, had an operation on his arm, and is still too weak to speak to investigators, the NTSB said.
Even after they get to interview Siebold, Hart cautioned, the investigation was far from over. "We are a long way from finding the cause," he said. But we're also a lot closer than we were on Friday.