SRB's
g licitis
once the are lit that the continue burning till all of the fuel is
consumed. My question is, what happens if only one SRB ignites and the
other one doesn't. Is there a way to extinguish them on the ground
that dosn't apply once the shuttle is in flight. Also what happens
if a SRB accidentaly ignites while the shuttle is being transported
or is sitting on the lunch pad?
Gunars Licitis
Roger J. Noe
> once the are lit that the continue burning till all of the fuel is
> consumed.
Or until they are destroyed.
> My question is, what happens if only one SRB ignites and the
> other one doesn't. Is there a way to extinguish them on the ground
> that dosn't apply once the shuttle is in flight. Also what happens
> if a SRB accidentaly ignites while the shuttle is being transported
> or is sitting on the lunch pad?
> Gunars Licitis
Pinwheel disaster. No extinguishing. (lunch pad?) Loss of vehicle,
transporter, and probably life. But don't worry too much about that.
Solid rockets don't get lit accidentally too often.
David Messer
> once the are lit that the continue burning till all of the fuel is
> consumed. My question is, what happens if only one SRB ignites and the
> other one doesn't.
The shuttle will tip over and explode.
>Is there a way to extinguish them on the ground
> that dosn't apply once the shuttle is in flight.
No.
> Also what happens
> if a SRB accidentaly ignites while the shuttle is being transported
> or is sitting on the lunch pad?
It would be bad.
--
David Messer UUCP: ...ihnp4!quest!dave
...ihnp4!encore!vaxine!spark!14!415!sysop
FIDO: 14/415 (SYSOP)
Lyle McElhaney
It has always been understood that such a situation on the space shuttle
would be a catastrophic failure. The chances of one SRB not igniting is
pretty low; there are multiple redundant ignitors (the rough equivalent of
shaped charges at the top of the cavity) and starters. But if it happened,
the astronauts are left with the tuck 'n' roll procedure. That's about
all.
Lyle McElhaney
...hao!cisden!lmc
Bruce T. Lowerre
> > once the are lit that the continue burning till all of the fuel is
> > consumed. My question is, what happens if only one SRB ignites and the
> > other one doesn't.
>
> The shuttle will tip over and explode.
That may happen eventually, but not right away. The launch vehicle is held
down to the pad until all engines are ignited. The three main liquid engines
are ignited first, then the SRBs. If one did not ignite, I suspect the
procedure is to shut down the main engines and not release the vehicle. The
question is how much the launch structure can take from the heat and forces
of an SRB burn before something lets go.
Henry Spencer
> down to the pad until all engines are ignited. The three main liquid engines
> are ignited first, then the SRBs. If one did not ignite, I suspect the
Alas, not so. I thought so too, but on looking it up in the Space Shuttle
News Reference (available from NSI), it turns out that SRB ignition and the
blowing of the hold-down nuts are simultaneous.
It is very unlikely that one SRB would quietly fail to ignite. They are
ignited by a substantial rocket motor up in the top of the SRB firing down
into the center hole; this is pretty positive ignition! The actual ignition
system that ultimately gets things going is multiply redundant.
--
Henry Spencer @ U of Toronto Zoology
{allegra,ihnp4,linus,decvax}!utzoo!henry
Ken Montgomery
> > > I have a question about the SRB's. The way I understand it is that
> > > once the are lit that the continue burning till all of the fuel is
> > > consumed. My question is, what happens if only one SRB ignites and the
> > > other one doesn't.
> >
> > The shuttle will tip over and explode.
>
> That may happen eventually, but not right away. [...]
> If one [SRB] did not ignite, I suspect the
> procedure is to shut down the main engines and not release the vehicle. The
> question is how much the launch structure can take from the heat and forces
> of an SRB burn before something lets go.
>
> [Bruce T. Lowerre]
The question is how to *hold down* a launch vehicle which has even 1 SRB
firing! I gather that the SRB's are attached to the pad by rather hefty
bolts prior to launch, but everything has limits!
Also, I doubt the result of such a failure would be so calm as the vehicle
"tipping over"...
--
The above viewpoints are mine. They are unrelated to
those of anyone else, including my cat and my employer.
Ken Montgomery "Shredder-of-hapless-smurfs"
...!{ihnp4,allegra,seismo!ut-sally}!ut-ngp!kjm [Usenet, when working]
kjm@ngp.{ARPA,UTEXAS.EDU} [Old/New Internet; depends on nameserver operation]
Will Martin
>> ... the SRBs. If one did not ignite, I suspect the
>> procedure is to shut down the main engines and not release the vehicle...
>blowing of the hold-down nuts are simultaneous.
Some months ago, long before the accident, this was discussed on the
net, and I recall that one of the people "in the know" mentioned that
the SRB thrust was in excess of what the hold-downs could withstand.
If an SRB ignited and the hold-down was not released, they would take
off anyway, ripping apart the structure of the craft and causing a
massive explosion as all the fuel/oxidizer was spilled.
Will
Michael Wagner
>
>Are we would-be space explorers or blowflies?
>
>Barb
Blowflies?
Is this a comment on how rocket technology works? :-)
Michael Wagner (wagner@utcs)
Henry Spencer
> >blowing of the hold-down nuts are simultaneous.
>
> If an SRB ignited and the hold-down was not released, they would take
I'm a bit surprised that the hold-downs can't take full SRB thrust -- the
Saturn V hold-downs could and did take its (rather higher) full thrust, since
they weren't released until the engines were at full power -- but maybe
there was some sort of compromise needed in the engineering for the Shuttle
hold-downs. It would explain the timing.
Kurt Allen
> once the are lit that the continue burning till all of the fuel is
> consumed. My question is, what happens if only one SRB ignites and the
> other one doesn't.
The information I have seen in Aviation Week and Space Tech. says that
this would result in destruction of the orbiter and all aboard.
Ron Natalie <ron>
> Saturn V hold-downs could and did take its (rather higher) full thrust, since
> they weren't released until the engines were at full power -- but maybe
> there was some sort of compromise needed in the engineering for the Shuttle
> hold-downs. It would explain the timing.
I remember watching a film of a test where the shuttle was fired while
being restrained, or was this just the SMEs?
-Ron
Dave Hsu
The clips of SRB testing that I remember showed them being held down
like the Saturn V's tested parts...strapped to the ground in a horizontal
position. Perhaps you're thinking of the launch footage, in which the SME's
ignite, the whole assembly rocks to one side, and the SRB's are ignited
when it squats back to its original position before being released.
-dave
--
David Hsu Communication & Signal Processing Lab, EE Department
<disclaimer> University of Maryland, College Park, MD 20742
h...@eneevax.umd.edu {seismo,allegra}!umcp-cs!eneevax!hsu
ARPA n. [acronym for Advanced Research Projects Agency.] An agency of the
U.S. Department of Defense established in 1968 to test its defenses
against misuse and piracy in the large-scale distributed processing
environment.
-Stan Kelly-Bootle, "The Devil's DP Dictionary"
I appreciate Bo Derek for her mind.
> >being restrained, or was this just the SMEs?
> >
Correct: just the main engines. You can see film of such a test in
"The Dream Is Alive". The hold-down system can obviously restrain the
shuttle system when only the main engines are burning, but I can't think of
any practical way to hold it down once the SRBs are lit.
--Craig
...ucbvax!pixar!good