Path: utzoo!attcan!uunet!mcvax!ukc!reading!cf-cm!cybaswan!iiit-sh
From: iiit-sh@cybaswan.UUCP (Steve Hosgood)
Newsgroups: sci.space.shuttle
Subject: Possible Disaster Scenarios
Keywords: launch, disaster :-(
Message-ID: <73@cybaswan.UUCP>
Date: 8 Sep 88 09:28:23 GMT
Organization: Institute for Industrial Information Technology
Lines: 54

We've seen one way that a shuttle can be lost :-(.

Is there any way to prevent the following possible failure modes resulting
in another such loss?

1) Not all the explosive bolts holding the stack to the pad blow. Assuming
	worst case, if all bolts on one side held firm after the Solid Rocket
	Boosters ignite, you'd have a force in the region of 2.9 Million
	pounds acting to twist the stack around the fixed point, which I
	suspect could easily throw the whole lot into the deck next to the
	pad. Assuming the External Tank would rupture, the resulting
	explosion would probably level every structure at KSC for miles.
	(In practice the rogue explosive bolts would probably snap before
	that point, which would cause the vehicle to launch off-vertical.
	Can that be corrected-for?)

2) What happens if one of the SRBs doesn't light up? I assume the launch
	sequencer doesn't blow the bolts, kills the liquid fuelled engines
	and attempts to hold the stack on the ground until the one SRB goes
	out? Can the pad take that sort of blasting? Can the external tank
	remain cool enough to avoid risk when it's sat next to an SRB at
	full bore without the airflow to cool it?

3) What happens if the liquid fuelled engines flame out just after lift-off?
	This is probably the least dangerous problem, the 2 SRBs I believe
	provide about 5.8 Million Pounds force between them, and the 3 liquids
	supply "only" about another million between them. The shuttle may not
	get into orbit, but at least it should have a chance of attaining
	about 15-20 miles altitude, which ought to be fairly safe.. Are these
	figures right? (Within +/- 50% I mean :-))

Sorry to be raising such gloomy points, but it's worth noting that Gen. Chuck
Yeager owes his life to such discussions of doom. Someone once asked "what
would happen if you drop in the X-1 from the carrier aircraft and find you
have a total power failure? You can't fire the rockets and end up doing a
dead-stick landing with a full load of fuel onboard that can't be dumped.
The undercarriage'll never take the strain." As a result they fitted a manual
fuel dump valve.  It was needed in earnest soon afterwards. Read Yeager's book
(called "Yeager") for details. I quite enjoyed it.

BTW, I was glad to see the Soviets managed to sort out their problem in
returning those Cosmonauts from Mir. I wonder why they jettison the docking
module before tring to fire the retro rockets to commence re-entry? Surely
there would be time enough afterwards? (Followups on this last point to
sci.space please).

-----------------------------------------------+------------------------------
Steve Hosgood BSc,                             | Phone (+44) 792 295213
Image Processing and Systems Engineer,         | Fax (+44) 792 295532
Institute for Industrial Information Techology,| Telex 48149
Innovation Centre, University of Wales, +------+ JANET: iiit-sh@uk.ac.swan.pyr
Swansea SA2 8PP                         | UUCP: ..!ukc!cybaswan.UUCP!iiit-sh
----------------------------------------+-------------------------------------
            My views are not necessarily those of my employers!