Experts with experience of flying rocket-powered vehicles are closely studying images showing the breakup of SpaceShipTwo and pieces of the wreckage as they fell into the Mojave Desert. While they caution that investigators from the National Transportation Safety Board have only just begun what will be an exhaustive examination of both the last minute in the life of the vehicle and the wreckage, some clues are already emerging that draw attention away from the untested rocket motor itself to the craft’s structure
I asked a former NASA astronaut, who cannot be quoted on the record, to look at photographs of the debris. The most-intact section of this image is the dark, bowl-shaped object. This looks similar to what is called a pressure bulkhead in airplanes that seals the part of the fuselage that is pressurized from the rest of the structure.
However, the former astronaut believes this to be the top of the craft’s oxidizer tank.
“The tank contains the oxidizer nitrous oxide and not fuel, which is a solid plastic in the motor, so I would have thought it would be very stable and not too heat sensitive. If it is the tank, then it looks reasonably intact, suggesting it did not fail. And the solid rocket propellant would not blow up in one explosion since it cannot do that without an oxidizer. It could have had a burn-through like Challenger Shuttle, but I would have thought that would take longer.
“So keeping in mind the evidence is paltry at this time, I think it is possible that the crew module pressure vessel failed structurally resulting in a massive depressurization event followed by breakup. That would explain why we do not see any cabin, although it could be out there, and just not filmed. It would also explain the photograph that shows the engine still burning as the breaking up vehicle tumbles tail first.”
The wreckage is distributed over a wide area, but experts believe that investigators will quickly be able to reconstruct the sequence of events leading to the craft’s breakup – and identify what initiated the catastrophic and virtually instantaneous failure.
Arriving at the crash site, the acting head of the NTSB, Christopher Hart, said he did not know if the craft had a flight recorder (“black box”) on board. However, all the flights were monitored by ground controllers who would have detailed streams of data from which they would be able to analyze the breakup second-by-second. The crew of the WhiteKnightTwo, the mother ship from which the spacecraft was launched, would also have had a very close (and horrifying) view of what happened. They will be debriefed by the investigators.
Sir Richard Branson, Virgin Galactic’s chief, said at a press conference Saturday:
“We owe it to our pilots to find out what went wrong, if we can overcome it we will make absolutely certain that the dream lives on.”