dietz%usc-cse%USC-ECL%SRI-NIC@sri-unix.UUCP (12/23/83)
AW&ST reported that the shuttle fire was caused by a hydrazine leak somewhere in the aft compartment near two APUs. The leak could have occured in space, where the hydrazine would have frozen as it leaked out. Upon returning to the atmosphere the hydrazine could have vaporized and ignited. The APUs' hydrazine valves are spring loaded and shut themselves automatically when their power failed (this was some minutes after landing). Heat buildup caused some components in the fire area to explode. Another interesting thing happened on this flight. Parts of the devices that thrust the SRB's away from the shuttle after separation were found embedded in the SRB casings. There was concern about possible damage to the shuttle's thermal protection tiles. And, I imagine, possible catastrophic punctures of the external tank on future flights. Boom!