[net.columbia] SRB's

mangoe@umcp-cs.UUCP (Charley Wingate) (02/07/86)

>> Just heard they are saying that it WAS a burn through of the left SRB, and
>> that it can be seen from  other camera angles.

>> Can anyone explain why off earth the thing didn't go tumbling madly
>> after seperating? How there was no apparent sign of flame from the side of
>> the SRB after seperating?

I can't explain the former, but on the low-magnification film that was
originally released, you can see the extra plume.  It appears on the right
booster (which is on the left side of the picture) immediately after the
explosion.  There is clearly a plume coming out of the side of the booster
in the right place, and the loop in the contrail is in the right direction
according to Newton.

C. Wingate

gjl@ihwpt.UUCP (g licitis) (02/14/86)

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. 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
					

rjnoe@riccb.UUCP (Roger J. Noe) (02/15/86)

> 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.

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.

dave@quest.UUCP (David Messer) (02/16/86)

> 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.

>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)

lmc@cisden.UUCP (Lyle McElhaney) (02/17/86)

> 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. 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?

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

bl@hplabsb.UUCP (Bruce T. Lowerre) (02/25/86)

> > 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.  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@utzoo.UUCP (Henry Spencer) (02/26/86)

> 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...

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

kjm@ut-ngp.UUCP (Ken Montgomery) (03/05/86)

[]

> > > 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]

wmartin@brl-smoke.ARPA (Will Martin ) (03/05/86)

In article <6435@utzoo.UUCP> henry@utzoo.UUCP (Henry Spencer) writes:
>> ... the SRBs.  If one did not ignite, I suspect the
>> procedure is to shut down the main engines and not release the vehicle...
>... SRB ignition and the
>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

barb@oliven.UUCP (Barbara Jernigan) (03/07/86)

> ...The actual ignition
> system that ultimately gets things going is multiply redundant.
> 				Henry Spencer @ U of Toronto Zoology

As was proven by the mission (a year or two ago) that aborted at, what was it,
three seconds to launch?  One would think, getting up at 5 or so in the a.m.
I would have been disappointed -- but I cheered.  The "failsafes" *worked*!
(But then, I'm in QA, and I appreciate programs that abort gracefully.)

The recent disaster is a festering wound in the shuttle's reputation -- but
let's not forget all the successes (and admirable they are, indeed)!

Are we would-be space explorers or blowflies?

Barb

wagner@utcs.uucp (Michael Wagner) (03/09/86)

In article <528@oliven.UUCP> barb@oliven.UUCP (Barbara Jernigan) writes:
>
>Are we would-be space explorers or blowflies?
>
>Barb


Blowflies?

Is this a comment on how rocket technology works?  :-)

Michael Wagner (wagner@utcs)

henry@utzoo.UUCP (Henry Spencer) (03/11/86)

> >... SRB ignition and the
> >blowing of the hold-down nuts are simultaneous.
> 
> ...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...

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.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry

allen@mmm.UUCP (Kurt Allen) (03/14/86)

> 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 information I have seen in Aviation Week and Space Tech. says that
this would result in destruction of the orbiter and all aboard.

ron@brl-sem.ARPA (Ron Natalie <ron>) (03/19/86)

> 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.

I remember watching a film of a test where the shuttle was fired while
being restrained, or was this just the SMEs?

-Ron

hsu@eneevax.UUCP (Dave Hsu) (03/20/86)

In article <117@brl-sem.ARPA> ron@brl-sem.UUCP writes:
>> 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.
>
>I remember watching a film of a test where the shuttle was fired while
>being restrained, or was this just the SMEs?
>
>-Ron

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
hsu@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"

good@pixar (I appreciate Bo Derek for her mind.) (03/22/86)

> >I remember watching a film of a test where the shuttle was fired while
> >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