Still no answer:
“I can tell you for certain that, when we do determine the cause, that it will be published so that it can’t happen to others,” Rutan said. “But we don’t know yet what caused the detonation.”
This seems to me a serious setback. If I were them, I’d be talking to XCOR and others, and doing a vehicle redesign to accommodate a different (liquid, not hybrid) engine. They have been overhyping the safety of hybrids for too long on this program, and the fact that they killed three men and wounded three more is going to have an effect on the perception of the engine’s safety, even if it was not something that could rationally be expected in flight. As long as they don’t know what happened, they can’t move forward. They’re sort of in the same position as NASA, dealing with an unknown risk, but betting on the come, and hoping that they’ll have it figured out in a year or so, in time to start flight tests under rocket propulsion. But as I said, hope is not a plan.
NASA’s problems are much more cultural then Scaled’s. We’re also talking about a known problem versus an unknown.
I think NASA can afford to redesign the Ares once again since it’s still only on paper. I highly doubt Scaled and Virgin can afford to scrap the program and start with a new propulsion system without massive influx of capital and delays going out years.
Glenn Reynolds had an apt comment on this in the RedBlue podcast: (paraphrasing) As far as industrial accidents go, that was pretty minor. If it had happened in a plant making – oh, mobile homes – nobody would have cared.
“Ed Minchau said:
If it had happened in a plant making – oh, mobile homes – nobody would have cared.”
But if that accident could somehow translate into mobile homes spontaneously combusting once out on the open road then I believe that would raise some level of concern as well.
Seems to me that the explosion had more to do with the choice of N2O as an oxidizer than the engine being a hybrid. A hybrid using O2 or other non-explosive oxidizer would need a more complex ignition system, but not be subject to most explosive failure modes.
The issue with LOX, as I understand, is that it readily oxidizes just about anything if you let it escape, for example your airframe.