My condolences to Michael Alsbury's friends and family, and wishing Peter Siebold a speedy recovery.
ust guessing here, like I did on 9/11, but I would suspect a crack in the fuel. These are hybrid rocket engines- solid fuel, but a separate oxidizer. I think the first one used rubber cement and Nitrous Oxide (NO2). Supposed to be the safest ever designed- safe components, and they can be throttled, shut down, and restarted. However, I seem to recall one of these engines failing under static test and killing some of the employees. Perhaps this fuel mix was designed to prevent that. Wondering if it wasn't too rigid, and when subjected to the thermal and mechanical stresses of flight at low temperatures, it cracked. Cracks would make way too much surface area, and when the oxidizer hits them, I would guess the energy widens the cracks, which makes more surface area, which accelerates the reaction, etc. etc.
NASA, and now private space launch companies, have been having a TON of accidents lately. I imagine the Tinfoil Hat crowd will be calling "Sabotage!" and "Conspiracy!" in short order. Although in the words of Gen. William Tecumseh "Uncle Billy" Sherman, "Once is happenstance, twice is coincidence, but three times is enemy action." It would be damned easy to sneak a chunk of some sort of explosive into the fuel when it was cast, or when the motor was assembled. This happened right on the heels of the failure of an unmanned Orbital Sciences 'Antares' rocket last Tuesday. If the US space program crashes and burns, we'll still be stuck paying the Russians to launch stuff for us.

Wait- a Russian 'Proton' class booster suffered a first-stage failure in July of last year- breaking a 30 year stretch without a first-stage failure.

But they seem to have fixed that- they're flying them again on the ISS resupply missions, and they're launching 'Soyuz' class heavy boosters like they're going out of style. We need Brad Meltzer, Jesse Ventura, Richard Belzer, and Dr. Jim Fetzer to look into this.

Hey, most of those guys have "zer" in their names. Coincidence? I think not!
kham wrote:Look at the exhaust shockwaves in the 2nd image; they look very normal, the diamond-shapes you'd expect in a clean burn. Whatever went wrong must have been abrupt, and terminal