fisher@dvinci.DEC (Burns Fisher, MRO3-1/E13, 231-4108) (07/05/84)
After the engine shutdown on Discovery, the TV pictures (via NBC) showed what
appeared to be a ~small(?) fire in the area of the engines. The NBC
man-at-KSC asked his astronaut/consultant about it. The astro replied that
he thought it was a normal part of the shutdown. Does anyone know anything
more about this? (By the way...while I have to give NBC credit for continuing
to cover shuttle launches, their coverage is truly abysmal! Bryant Gumbel
is the biggest flamer I have ever seen, with the possible exception of Jules
Bergman! B.G. seemed to be nearly in a panic wondering why the astros did
not get out of the shuttle. They kept trying to get the astro/consultant to
admit that everyone was within an inch of loosing their life. They kept
alluding to what a close thing it was...only 4 seconds later and it would have
been all over. [I would like to ask them how the hell you are supposed to
detect that an engine has not fired correctly before it is supposed to fire
at all!]).
Also, it appeared that water was being used as a fire extinguisher around the
base of the shuttle after the shutdown. Will water really put out an LH2 fire?
Or is it for some other purpose?
Thanks,
Burns
UUCP: ... {decvax|allegra|ucbvax}!decwrl!rhea!dvinci!fisher
ARPA: decwrl!rhea!dvinci!fisher@{Berkeley | SU-Shasta}stevel@haddock.UUCP (07/07/84)
#R:decwrl:-234400:haddock:10400003:000:370
haddock!stevel Jul 6 11:15:00 1984
It is standard procedure to shoot water all over the thrust deflectors
just below the engine starting just before launch. This help keep
the metal from melting away, or just weakening too much. That is
probably what you saw. I assume the engine just burned itself out
once the fuel was shut off.
Steve Ludlum, decvax!yale-co!ima!stevel, {amd70|ihnp4!cbosgd}!ima!stevelalb@alice.UUCP (Adam L. Buchsbaum) (07/08/84)
The water system is not to prevent metal from melting. It was installed after STS-1 to help cushion the giant shockwave resulting from SRB ignition. As some may recall, it was this shockwave that ripped off most of the lost STS-1 tiles as well as bent some support structures. The water system, which begins to fire seconds before SSME ignition, shoots 100,000 gallons of water per second throughout the flame trench. Also, there are bags of water under the SSME's and SRB's. These are, of course, blown into oblivion. I don't know whether or not the water system that was used to put out the fire was this shockwave suppression system or not. Adam
giles@ucf-cs.UUCP (07/09/84)
(1): Yes, there was a small hydrogen fire in the tail of the orbiter after
the aborted launch. Fire suppression equipment in the rear of
the orbiter put it out without difficulty.
(2): That water may have been the sound suppression system in action. I
have not seen the entire launch sequence on tape yet, so I can't say
that was the source of the water for sure.
The sound suppression system, for those joining us late, is required
because the launch pad is a giant slab of concrete. Apparently the
old Saturn Vs had a relatively quiet ignition; when the SRBs of the
Shuttle ignite, a *very* strong shock wave leaves the engines, hits
the pad, and bounces straight back into the ET and orbiter. (Note:
this was not anticipated, in part because the SRBs had not been fired
on the launch pad, as the SSMEs had.)
According to one of my former professors (who monitored air quality
during the launch) NASA determined that the most dangerous point of
STS-1 occured just a few seconds after launch -- when this echo was
reverbating throughout the orbiter and ET. In fact, they found a
four-foot reinforcement rod bent in the orbiter's nose. Add this to
the well documented "walk" of the orbiter across the launch pad and
Young & Crippen had an interesting couple of seconds.
Anyway, instead of rebuilding the launch pads (out of nice fireproof
soundabsorbing materials) NASA decided to dump a couple of tons of
water between the Shuttle and the pad. The general idea is that the
acoustical energy will be spent breaking the water drops into water
vapor, instead of the Shuttle system into a giant fire-cracker.
I recall that there was quite a bit of debate at the time over the
usefulness of this approach, but it apparently has worked.
Bruce Giles
{decvax, duke}!ucf-cs!giles university of central florida
giles.ucf-cs@Rand-Relay orlando, florida 32816phil@amd.UUCP (Phil Ngai) (07/09/84)
After rereading my article I wanted to clarify that the leaking H2
was probably coming out of the engines after they were shutdown.
Not that the valves leaked, but that there would be left over gases.
--
From Joe's Foo bar and grill
Phil Ngai (408) 982-6554 {ucbvax,decwrl,ihnp4,allegra,intelca}!amd!philstevel@haddock.UUCP (07/14/84)
> The sound suppression system, for those joining us late, is required > because the launch pad is a giant slab of concrete. Apparently the > old Saturn Vs had a relatively quiet ignition; when the SRBs of the > Shuttle ignite, a *very* strong shock wave leaves the engines, hits > the pad, and bounces straight back into the ET and orbiter. I belive the Saturn V had a water spray system like the shuttles. I don't know if it was kept when the pad was rebuilt. Maybe it wasn't enough for the SRB's. Does anybody out there know?
phil@amd.UUCP (Phil Ngai) (07/15/84)
Doesn't anybody read War-Monger Weekly aka Aviation Leak aka Aviation Week?
It says there was a fire, probably caused by leaking H2 and that they had
to spray water on it several times to put it out. There is a sprinkler
system specifically for such a contingency.
If you guys don't read Aviation Week, you are missing out on some gorgeous
shuttle photos. Makes me proud to be an American...
--
From Joe's Foo bar and grill
Phil Ngai (408) 982-6554 {ucbvax,decwrl,ihnp4,allegra,intelca}!amd!phil