Failure modes of segmented solid rocket boosters

Question

The Rogers Commission Report (PDF, page 73) describes the Space Shuttle Solid Rocket Boosters as

[...] a faulty design unacceptably sensitive to a number of factors. These factors were the effects of temperature, physical dimensions, the character of materials, the effects of reusability, processing, and the reaction of the joint to dynamic loading.

What are the failure modes for segmented solid rocket boosters?

Pretty darn broad question, I'm thinkin... – Digger Feb 12 '17 at 06:08 — Digger, Feb 12 '17 at 06:08
Failure modes: not working; catching fire; exploding. – iAdjunct Feb 13 '17 at 03:04 — iAdjunct, Feb 13 '17 at 03:04

score 5 · Accepted Answer · answered Apr 16 '18 at 06:26

5

In the case of the Space Shuttle's SRBs, the biggest risk came from an inexcusably bad design for the segment joints that actually increased the gap when the SRB was ignited and the motor casing was placed under pressure.

answered Apr 16 '18 at 06:26

So only one of the two redundant O-rings seals was functional, the other did not inrease reliabilty at all. – Uwe Jun 05 '19 at 14:38
I would say that in a system where the upper O-ring could seal, the lower one could provide backup. It appears, however, based on the observed number of O-ring failures, that it was common for joint rotation to overwhelm the upper O-ring and thus, only the lower O-ring worked. Except of course, for when the lower O-ring also failed. – Jun 06 '19 at 00:51

Failure modes of segmented solid rocket boosters

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