[net.space] SRB Seal Failure Detail

wmartin@ALMSA-1.ARPA (Will Martin -- AMXAL-RI) (03/12/86)

One point I have not seen answered in the net and TV publicity on the
SRB seal failure:

Was there any reason that the seal failed at the particular point it
did, creating the jet of high-temperature gasses that had the subsequent
effect of melting or weakening the attachment hardware? Or was this
simple bad luck? If the seal was going to fail anyway, could it have
just as readily failed at some other point in the joint's circumference,
maybe jetting out into the air instead of back toward the external tank?

If it had failed in the latter fashion, I get the impression that the
flight could perhaps have continued successfully -- the only ill effect would
have been a minor loss of thrust from the defective SRB, which probably
could have been compensated for with normal procedures. Is this the case?

Or is there something about the configuration of the SRB segment seal that
made it likely or inevitable that, if a seal failure would occur, it would
happen at the point it did, thus having the disastrous effects we saw?

Will Martin

ARPA/MILNET: wmartin@almsa-1.ARPA     USENET: seismo!brl-bmd!wmartin

dietz@SLB-DOLL.CSNET (Paul Dietz) (03/12/86)

>Was there any reason that the seal failed at the particular point it
>did, creating the jet of high-temperature gasses that had the subsequent
>effect of melting or weakening the attachment hardware? Or was this
>simple bad luck? If the seal was going to fail anyway, could it have
>just as readily failed at some other point in the joint's circumference,
>maybe jetting out into the air instead of back toward the external tank?

The flame quickly spread around the joint.  At the time of the explosion
flame was coming out along an arc of ~ 315 degrees.  It's amazing the
steel retaining pins in the SRB joint held.

wmartin@ALMSA-1.ARPA (Will Martin -- AMXAL-RI) (03/14/86)

Thanks to all who responded, including those I can't mail back to direct!

I've gathered that the cause of the leak location was a combination of
the hot gassess, once they reached the O-ring, following its channel
around the cicumference of the SRB, thus creating a wide-spread leak,
plus the chilling effect being greater at certain locations. 

Regards, Will