I agree with what has been said but I think there's a little more to add.

>The solid rocket boosters are ammonium perchlorate, aluminum and binder.
>The failure was due to a combination of poor judgement on managment's
parts, and
>bad luck.

... and less adequate initial design than could have been achieved at
minimal extra cost.
The weaknesses of the original joint design that were subsequently corrected
were well known in advance.

Of course, hindsight is a marvellous thing. The joint design was such that
it "opened up" under pressure placing greater demands on the O-ring.
The post-Challenger redesign placed a "trapping" ring (or finger in cross
section view) which stopped the joint opening up under pressure.
That said, the decision to launch at below design ambient temperature as a
consequence of "political" pressure was a significant factor.


Really bad ASCII drawing of old and new joint designs.

x is one case half.
y is other case half
O is O=ring.


Old

      yyyyyy
xxxxxxOyyyyy

New
        xxxxx
        xx yyyy
xxxxxxxxOyyyyyy



regards,



                Russell McMahon

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