Originally Posted by
tdracer
You can kill the effective thrust relatively easily - ejecting the nozzle being one way - by getting rid of the high pressure within the 'combustion chamber' which will greatly slow the burn rate of the propellant (along with lacking a proper nozzle to accelerate the exhaust). In my hobby rocketry, the failure of the bottom (i.e. nozzle) or top closure stops any effective acceleration of the rocket (not a particularly uncommon failure).
OTOH, getting the propellant to stop burning is next to impossible - it'll burn just fine underwater - although on occasion the 'shock' of going from several hundred PSI to ambient pressure in an instant can cause pieces of the propellant to self-extinguish leaving bits of propellant in the debris. But even when that happens, it won't extinguish all the propellant, just parts.
All that being said, I'm unaware of any serious work on a system to kill the thrust from the solid boosters for Artemis. Rather, the emphasis was on the launch escape system being able to pull the capsule away from any catastrophic failure of the booster. It's significant that the launch escape system is not jettisoned until several seconds after the solid boosters separate.
I seem to recall that during the Shuttle days, killing off the SRBs was discussed. Blowing open the casing with an explosive charge was the only offered solution but it was never incorporated into the system. I may have misremembered but I think it was mentioned in '
Truth, Lies and O-rings' by Allan McDonald.