gandalf@pro-electric.cts.com (Ken Hollis) (04/24/91)
Greetings and Salutations: From: jonkatz@gn.ecn.purdue.edu (Jonathan W. Katz) Subject: Re: Fire near tail of shuttle after landings. >Actually, what he saw back in '85 (?) was an actual fire in the Columbia >engine room that did a lot of damage. Run that by me again? About the only one I can recall is when APU #1 & APU #3 blew up on landing on STS-9, late 1983 due to a cracked GGVM (Gas Generator Valve Module (A fancy term for a fuel injector)). This was caused by fatigue failure & stress, as it has to undergo pulsing several times per second, temperatures to 1200 degrees Fahrenheit & pressures 40 PSIA (Pounds Per Square Inch Atmosphere) to 1300 PSIA. It also did a surprisingly small amount of damage considering what happened. By the way, it is the Aft compartment, not the engine room. You might have noticed on the IR camera that the aft RCS (Reaction Control System) thrusters were also firing when the shuttle was coming in for landing. From: digex@world.std.com (doug e humphrey) >Another possibility would be them burning off Hydrazine, which >is used for the various small positioning thrusters. Does anyone >know for sure what they do with the leftover Hydrazine in the >shuttle after landing? Most of the MMH (Monomethylhydrazine) & Nitrogen Tetroxide is burned off from reentry (leaves maybe 10% when the mission is over?). When the shuttle lands, it is moved to the MDD (Mate / Demate Device) and the system is "safed". There is always residual fuels on board (maybe a couple hundred pounds for the forward RCS and the Aft RCS). They are just left in there. The Hydrazine in the APU's that is left over (and the pure ammonia from the ammonia cooling) is left on board until the tanks are and refilled for the next mission. From: jdeitch@umiami.ir.miami.edu (Jonathan Deitch) >Would a shuttle on the launch pad be able to withstand a tornado >without too much damage. Max winds for rollback (predicted) are Hurricane conditions. Of course this assumes that the predicted speeds are available a day or so before the winds are actually going to hit. This is the amount of time required to prep for rollback and rollback. If there is something sudden like a tornado, then they batten down the hatches and wait it out. Ken Hollis ---- ProLine: gandalf@pro-electric Internet: gandalf@pro-electric.cts.com UUCP: crash!pro-electric!gandalf ARPA: crash!pro-electric!gandalf@nosc.mil