Originally Posted by
tdracer
Could be from the ignition device they use - those ammonium-perchlorate based solid boosters are not easy to ignite, so some sort of highly energetic pyrogen is used to light the propellant.
Read somewhere that the solid boosters need to light off withing a few hundreds of a second of each other or the asymmetric thrust can cause catastrophic structural damage (at least that was the case of the Space Shuttle).
Using ammonium-perchlorate in my high-power hobby rocketry, trust me that getting both solid boosters to ignite within such a short time period is highly non-trivial...
To be honest I don't think so. it looks like concrete dust to me but the post launch pad photos will be interesting.
I cover the SRBs in my Shuttle STEM talk and the igniter is at the nose end of the booster with the reaction doing the job all along the thrust channel within the propellant. The propellant is moulded in a particular shape at the pointy end that exposes the maximum surface area at the moment of launch, which then reduces as the material burns. It is the only way to have any control over the amount of thrust generated. The geometry of the fuel causes the thrust to decrease by some 33% at 50 seconds after launch to avoid over-stressing the vehicle i.e. the exposed reacting area is lowered.
Yes, the ignition has to be timed to a millisecond otherwise the stack would become the world's largest Catherine wheel. I'm surprised that the SRBs are not recovered on Artemis. The nozzles gimbal for directional control however they never solved the problem of the expensive end smacking into the Atlantic first, causing some rather costly damage. The Shuttle missions only lost 2 SRBs over the entire programme (other than Challenger where they were intentionally destroyed), a remarkable record.
I was watching one Artemis II feed where the talking head insisted that the SRBs could be extinguished by the introduction of an inert gas. OFFS ! I'll do a better job for expenses, a cold beer and a ringside seat.
For Shuttle SRB solid fuel perforations, what is the shape of the double-truncated-cone? - Space Exploration Stack Exchange