Clark notes that tomorrow will be a time of remembrance in Mojave.
And one year later, they still don't seem to know for sure what happened. And we haven't heard what's going on with SpaceShipTwo propulsion development, though it won't fly before late next year (at least two years behind the original schedule, with some of that slippage no doubt due to last year's incident).
Oh it is known, Cal Osha is just incompetent.
A test at a temperature above the vapor transition point, along with a lot of sloppy procedures and a lack of grounding in an extremely dry and static prone environment.
= poof