"Truth, Lies, and O-Rings" is a fascinating (if sometimes tedious) book that should be at the top of any reading list for those interested in the Challenger disaster.
For me one of the more interesting side-bar discussions are those around deciding to use horizontal testing of the boosters despite that not being an operational configuration. This resulted in flexing of the joints that was not at all similar to the flight configuration and hindered identification of the weaknesses of the original "field joint" design.
1. In case anyone doesn't know, they use the actual recovered Shuttle casings on SLS, but use an extra "middle" section to make it 5 sections in length instead of the Shuttle's 4 sections. In the future they'll move to "BOLE" boosters which won't use previously flown Shuttle parts.
I think the booster was redesigned after the accident, I guess/hope the opportunity was seized to make a design that would be less sensitive to orientation.
> Are you saying that they are tested horizontally or that they are ONLY tested horizontally?
My understanding is that they are only hot fired horizontally.
Presumably there are many tests done at the component level, although it's questionable whether it makes sense to call those tests horizontal or vertical at that point.
For me one of the more interesting side-bar discussions are those around deciding to use horizontal testing of the boosters despite that not being an operational configuration. This resulted in flexing of the joints that was not at all similar to the flight configuration and hindered identification of the weaknesses of the original "field joint" design.