Originally Posted by
MechEngr
I recall some system for shutting down solid fuel motors by opening pressure reliefs and, after that, maybe some cooling gas would finish the job. At the least venting the pressure alone would eliminate the thrust. Not sure if it was investigated for the manned missions. Some propellants require both heat and pressure to release energy.
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.