I was watching. Flames erupted around the bases of the first stage and boosters. Looked like they were 6 to 8 feet tall, not pressurized but just licking around the cases. Black sooty smoke came from them, rising the entire length of the delta IV. I was expecting an explosive failure any second. I saw no signs of any extinguishers or other automated fire suppression. The flames just died out, as if whatever was burning had been completely consumed.
The fire looked like it was outside the nozzles!? Next to but Not the rocket boosters themselves, perhaps. But I believe the ignitores on these SRBs are well within the casings.
Frankly, since it didn’t blow up, it ought to take 5 minutes to figure out what was burning. Why and How ignited, that may be a challenge.
With Delta IV reliability, does anyone recall a similar incident, either on a single or heavy?
Has anyone wondered about sabotage yet?
Yes, there ARE flames deliberately started under the engines before the rocket motors start up, and those rocket motors start off and burn for a few seconds before the clamps release and the rocket begins “liftoff”.
The rocket motors have to start off before the rocket is released to stabilize fuel flow and oxidizer (liquid oxygen) flow to the burners before they can create the thrust to move the rocket up. (Thus the clamps holding everything sown to the concrete foundation.) The turbine exhausts receive the purging LOX liquid and liquid propellant for a few seconds as they cool down, and that mixture is explosive/flammable. If the rocket motor has ignoted, the purged gases and turbo exhaust just pass into the far larger exhaust flames and no problem results.
But before rocket engine ignition, big problems would obviously result. Thus the flames under the rocket before ignition: Those flames burn the vented oxygen and vented propellant at low rates around the bottom of the rocket before they accumulate and blow everything up.
Well, something sent wrong elsewhere, and so the rocket engines never reached “ignition” at countdown steps between 5 and “0” . “0” being “release the hold down clamps”.
That is normal ... occurs at every launch of a Delta-IV, when they burn off accumulated hydrogen around the launch pad. The announcer even explained it. Numerous Ewe-tewb videos also discuss this.