"The Challenger Disaster" airing November 16th at 9PM

[wolfpack]

I can believe that it was deemed not economically viable to make a solid SRB.
Now SLS will use a 5 segment SRB.

I assume you mean a non-segmented SRB. Anything's possible, but could be really difficult. Long and narrow is bad for solids, and making it in one piece just complicates it more. Also, the propellant geometries are not the same in each segment.

I never thought about it before, but during the "twang"movement, those joints moved while the skirts on the pad did not.  Maybe the joints were needed.  I also just noticed that at around the 70 second mark, the SRB's thrust is ramping up along with or close to the SSME's going back up to 104%.

What a complex, yet amazing system.  The people power used to harness physics involved is amazing.

Joint rotation was occuring at booster ignition (after the twang). The overpressure wave travelling down the bore of the SRB caused casings to bulge and the joints to rotate towards "open". It was unexpected. Originally Thiokol thought the joints would rotate towards "closed". MSFC, as I recall, never agreed with that analysis.

[Lars_J]

I wonder if the the Challenger and Columbia incidents never happened, if Shuttle would be flying today?

If the Challenger accident hadn't occurred, another accident would have happened with likely similar results. The system up until STS-51L was not safe, and one could argue that it was the process and design improvements made after Challenger allowed the Shuttle system to operate for as long as it did before the Columbia accident. And there were close calls before that.