Shuttle 51-L and Titan 34D-9 vehicle failures, both of which occurred
in 1986, resulted in major reassessments of each vehicle's design,
processing, inspection and operations. While the Shuttle SRM insulation/
propellant integrity was not implicated in the 51-L failure, the
intent is to preclude a failure similar to that experienced by Titan.
The RSRM field joint is quite tolerant of unbonded insulation. It
has sealed insulation to prevent hot combustion products from reaching
the insulation-to-case bond line. The bonding processes have been
improved to reduce contamination potential, and the new geometry
of the tang capture feature inherently provides more isolation of
the edge insulation area from contaminating agents. A greatly enhanced
Non-Destructive Evaluation program for the RSRM has been incorporated.
The enhanced non-destructive testing includes ultrasonic inspection
and mechanical testing of propellant and insulation bonded surfaces.
All segments will again be X-rayed for the first flight and near-term