Discussion:
Thoughts on VSE Launch Vehicles
(too old to reply)
The Apprentice
2005-07-12 06:27:45 UTC
Permalink
OK, here's my "If I were Griffin" launch vehicle selections. I'm not a
big fan of the SRB solution, as you'll see.

Replacement Saturn-IB: Two Atlas-V cores (roughly 2Mlbf total) strapped
on to a new core with a single SSME upper stage - it's overpowered for
this application (it needs to be around 300Klbf I'm guessing), but
there's nothing else in that class besides J-2S… and why bother bringing
that old fart back when they could just use a throttled-back SSME, with
higher performance and a current production line (and commonality with
the HLLV below)? The core is based on Delta 4, although heavily
modified to use a SSME and mate with Atlas V's.

Replacement Saturn-V: Six uprated Atlas-V cores -- RD-170's or dual RD-
180's (12Mlbf thrust total) attached to a new core (air-started?) with
three SSME's (1.5Mlbf total) and the third stage using one SSME (again
the question, make it restartable for TLI or just bring back the J-2S?
I say improve the SSME). Personally I don't understand WHY they're so
intent on using the Shuttle tank??? By the time they're done modifying
it, it'll be a completely new tank anyway… might as well make it 10
meters diameter like the old S-II stage… and use a nice big 10 meter
payload fairing.

After CEV development is completed, bring back something like the RS-84
as a domestic replacement for the RD-180 for the Atlas V. Make it a
2Mlbf high-pressure hydrocarbon engine, and throttle it down for the base
Atlas V. Bring out a SSME Block III, with lower chamber pressure,
higher area ratio (now assuming air-start), and reduced cost (due to
lower pressures and simplified design). And, if some day EELV produces
something like a RL-60, it could potentially be used in place of the
single SSME on the replacement S-IVB stage... though I'm a little
skeptical of how many would be required.

Build two new pads or refurbish LC39 and make them state-of-the-art.
Both launch vehicles will use the same pads, with identical crew towers
(same height for accessing the CEV). They actually did this later on
with the Saturn-IB for the Skylab missions - put it on top of a "milk
stool" (girder taking up the extra height) and launched them from LC39
just like the Saturn-V. They found they could save a lot of money and
decommission the old Saturn-IB pads completely by using the "milk stool"
trick - they never needed them in the first place if they'd just used
milk stools.

So, we'll leverage both EELV (thus driving down their launch costs and
making the military happy) and Shuttle-derived hardware (where it fits
well), and build a pair of man-rated pads so our operations don't
interfere with their commercial operations and also because there will be
significant differences between VSE vehicles and EELV -- not the least of
which is the crew-access tower.

I would have like to have found a use for RS-68 and more for Delta 4 to
do, but frankly, the RS-68 is a dog and I doubt the cost savings of the
engine are a good trade-off on the 2nd stage of a moon-mission HLLV, and
it's too big to replace the J-2S... so there's no chair for it at the
table I'm afraid.
Derek Lyons
2005-07-12 16:01:59 UTC
Permalink
Post by The Apprentice
OK, here's my "If I were Griffin" launch vehicle selections. I'm not a
big fan of the SRB solution,
Nor a big fan of low cost either.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
Ed Kyle
2005-07-12 18:35:56 UTC
Permalink
Post by The Apprentice
OK, here's my "If I were Griffin" launch vehicle selections. I'm not a
big fan of the SRB solution
What is wrong with SRB? Why throw away an existing
motor that provides the thrust of more than two F-1
engines, when no other equivalent high-thrust motor/
engine is, or will soon be, available? Why choose a
liquid propulsion system when the solid motor option
is predicted to cost less? Why spend billions
reinventing something that already exists?

- Ed Kyle
Allen Thomson
2005-07-12 22:18:20 UTC
Permalink
Post by Ed Kyle
What is wrong with SRB?
It may be the perception, right or wrong, that for
manned launches its failure modes are less survivable
than for liquids. They certainly blow up much faster
and more spectacularly on failure than liquids.

Hardware can be replaced, if expensively. Killing
people engages emotions.

So, I suppose that the argument should be made on the
basis of probability of LOC per crew launch.
Rand Simberg
2005-07-13 01:32:32 UTC
Permalink
On 12 Jul 2005 15:18:20 -0700, in a place far, far away, "Allen
Post by Allen Thomson
Post by Ed Kyle
What is wrong with SRB?
It may be the perception, right or wrong, that for
manned launches its failure modes are less survivable
than for liquids. They certainly blow up much faster
and more spectacularly on failure than liquids.
Not to mention the fact that it can't be shut down, gracefully or
otherwise, other than destroying it.
Reed Snellenberger
2005-07-13 01:32:17 UTC
Permalink
Post by Rand Simberg
Not to mention the fact that it can't be shut down, gracefully or
otherwise, other than destroying it.
First, I don't think this is a requirement when you've got a launch
escape system (although it may be a convenience).

Second, I'm pretty sure that nobody has a plan for shutting down a Delta
or Atlas EELV in mid-flight that doesn't ultimately result in its
destruction, which makes this something of a red herring.

Third, a thrust termination system ought to be pretty do-able for the
Stick (as opposed to the shuttle, which is a fragile beastie). A shaped
charge to blow off the last segment of the motor would probably eliminate
most of the thrust.
--
I was punching a text message into my | Reed Snellenberger
phone yesterday and thought, "they need | GPG KeyID: 5A978843
to make a phone that you can just talk | rsnellenberger
into." Major Thomb | -at-houston.rr.com
Rand Simberg
2005-07-13 04:45:23 UTC
Permalink
On Wed, 13 Jul 2005 01:32:17 GMT, in a place far, far away, Reed
Post by Reed Snellenberger
Post by Rand Simberg
Not to mention the fact that it can't be shut down, gracefully or
otherwise, other than destroying it.
First, I don't think this is a requirement when you've got a launch
escape system (although it may be a convenience).
It was for the OSP program.
Post by Reed Snellenberger
Second, I'm pretty sure that nobody has a plan for shutting down a Delta
or Atlas EELV in mid-flight that doesn't ultimately result in its
destruction, which makes this something of a red herring.
The idea is not to shut it down to prevent destruction--it's to shut
it down to maximize the probability of a safe abort.
Post by Reed Snellenberger
Third, a thrust termination system ought to be pretty do-able for the
Stick (as opposed to the shuttle, which is a fragile beastie).
It would be a redesign of the SRB.
Allen Thomson
2005-07-13 02:34:53 UTC
Permalink
Reed Snellenberger [wrote]
Post by Reed Snellenberger
Third, a thrust termination system ought to be pretty
do-able for the Stick (as opposed to the shuttle, which
is a fragile beastie).
It would be a redesign of the SRB.
If the VSE is really going to use SRBs or similar, that's
something that might be tested on the ground. Take some SRBs,
strap them down horizontally, light them off, apply the
proposed TTS du jour, and see what happens. Should make for
good videos even if some fail and, who knows, one might work
acceptably for a manned Stick. I'd be interested to see what
happens if the back end of a burning SRB gets cut off by a
linear shaped charge wrapped around the bottom.
George William Herbert
2005-07-13 03:31:51 UTC
Permalink
Post by Reed Snellenberger
Post by Rand Simberg
Not to mention the fact that it can't be shut down, gracefully or
otherwise, other than destroying it.
First, I don't think this is a requirement when you've got a launch
escape system (although it may be a convenience).
Not necessarily, but many of the escape conditions are traumatic
from a SRB when they wouldn't be from a liquid booster.
Post by Reed Snellenberger
Second, I'm pretty sure that nobody has a plan for shutting down a Delta
or Atlas EELV in mid-flight that doesn't ultimately result in its
destruction, which makes this something of a red herring.
All we care about is the time period from fault detection through
the crewed payload vehicle exiting the blast or debris zone from
whatever could or is happening.

What the now-failed stage does after the crew are clear is not
our problem (though, it's someone's problem, and the range
safety people probably get to push the magic button sooner
or later...).
Post by Reed Snellenberger
Third, a thrust termination system ought to be pretty do-able for the
Stick (as opposed to the shuttle, which is a fragile beastie). A shaped
charge to blow off the last segment of the motor would probably eliminate
most of the thrust.
A lot of people think that's a great idea, until you look at
what it does to the thrust profile.

At the moment of effective separation, you get a nozzleless
rocket motor with an effective 12 foot nozzle, about 16,000
square inches worth, and a chamber pressure of about 900 PSI
(as I recall, references far away right now). Which works out
to a sudden thrust increase in a short duration pulse up to
around 15 million pounds of thrust, a factor of roughly 5 increase.

That will almost certainly exceed the structural margins
of everything forwards of the SRB...

"Bang".


-george william herbert
***@retro.com
Ian Stirling
2005-07-14 00:24:19 UTC
Permalink
Post by George William Herbert
Post by Reed Snellenberger
Post by Rand Simberg
Not to mention the fact that it can't be shut down, gracefully or
otherwise, other than destroying it.
First, I don't think this is a requirement when you've got a launch
escape system (although it may be a convenience).
<snip>
Post by George William Herbert
A lot of people think that's a great idea, until you look at
what it does to the thrust profile.
At the moment of effective separation, you get a nozzleless
rocket motor with an effective 12 foot nozzle, about 16,000
square inches worth, and a chamber pressure of about 900 PSI
(as I recall, references far away right now). Which works out
to a sudden thrust increase in a short duration pulse up to
around 15 million pounds of thrust, a factor of roughly 5 increase.
Ok, you've done a hell of a lot more of this stuff, but, this seems
a bit wrong to me.

Ok...
Chamber pressure is 600PSI at end of burn (900 at beginning).
I'm using this figure as this is the time when I guess the maximum mass
of gas will be there.
Chamber temp is 3300C.
Chamber size (at end) is 4m*40m.
Call it 480m^3.
If this was air, it'd be 600Kg or so.
At 45 bar and STP, 30000Kg, at 3600K, maybe 800Kg, taking into account
the lower molecular weight.

Actually, this sum was pointless, as if it's an open chamber, the speed
of sound is what's important - say 1Km/s, that's 40ms for the far end
to notice it's become open.
So, it's all over in 100ms or so.
But.

In 100ms, I don't think you're going to push the nozzle anywhere close
to far enough away that the chamber is effectively open.
So, at least a substantial fraction of the energy is not going to come
out vertically, but horizontally.

I wonder if cutting the nozzle off maybe halfway down the narrowing
to the throat is an option.
Douglas Holmes
2005-07-12 23:27:22 UTC
Permalink
Post by Ed Kyle
Post by The Apprentice
OK, here's my "If I were Griffin" launch vehicle selections. I'm not a
big fan of the SRB solution
What is wrong with SRB?
They are not safe.

Why choose a
Post by Ed Kyle
liquid propulsion system when the solid motor option
is predicted to cost less?
Because we already know the cost.
NASA is not known for underestimating cost.


Why spend billions
Post by Ed Kyle
reinventing something that already exists?
Good question!
I choose the existing EELV over spending billions to build another
experimental rocket that can lift less then the EELV with existing
technology.
Ed Kyle
2005-07-13 04:31:28 UTC
Permalink
Post by Douglas Holmes
Post by Ed Kyle
Post by The Apprentice
OK, here's my "If I were Griffin" launch vehicle selections. I'm not a
big fan of the SRB solution
What is wrong with SRB?
They are not safe.
Compared to what?

With only one failure in 226 flights, and that one
a noncatastrophic failure, SRB has a better record
than any other U.S. booster stage. A four-piece
EELV Heavy would be more complex, and therefore more
likely to fail, than a two-part SRB based launcher.

EELV was only designed to meet a 98% reliability
goal. Consider, for example, that three of the six
Delta IV CBCs that have flown have suffered failures
and that two of the six Delta IV upper stages that
have lit up in orbit (two on Delta III rockets) have
either failed outright or seriously underperformed.

A more reliable vehicle makes it easier to
design an escape system that will meet crew
survivability goals (escape systems have their own
odds of success/fail).

- Ed Kyle
The Apprentice
2005-07-13 05:35:00 UTC
Permalink
Post by Ed Kyle
Post by Douglas Holmes
Post by Ed Kyle
What is wrong with SRB?
They are not safe.
Compared to what?
With only one failure in 226 flights, and that one
a noncatastrophic failure, SRB has a better record
than any other U.S. booster stage. A four-piece
EELV Heavy would be more complex, and therefore more
likely to fail, than a two-part SRB based launcher.
EELV was only designed to meet a 98% reliability
goal. Consider, for example, that three of the six
Delta IV CBCs that have flown have suffered failures
and that two of the six Delta IV upper stages that
have lit up in orbit (two on Delta III rockets) have
either failed outright or seriously underperformed.
A more reliable vehicle makes it easier to
design an escape system that will meet crew
survivability goals (escape systems have their own
odds of success/fail).
The reliability predictions are a bunch of hand-waving. The truth is,
with satellites costing as much as they do, the contractors do the best
job they can, and then wave their hands around to make the ignorant
people in the room feel better. Nobody knows what the real reliability
is.

I'll grant that the SRB has an excellent reliability record, except for
the astronauts it killed on Challenger.

The Delta Heavy failed because it was the same CBC's used in a new
configuration. The upper stage failed because it was a new variation on
a 40 year old engine. What's the "single-stick"? A new variation of
the SRB used in a new configuration. Odds are, it will encounter new
problems in the new application.

We can only hope astronauts won't be killed when that happens.
Ed Kyle
2005-07-13 14:37:10 UTC
Permalink
Post by The Apprentice
I'll grant that the SRB has an excellent reliability record, except for
the astronauts it killed on Challenger.
SRB didn't kill the STS-51L crew. By most accounts,
they survived the initial breakup all the way down
to impact with Atlantic. What killed them was NASA
bean counting that decided, back in the early 1970's,
that an escape system cost too much.

- Ed Kyle
John Schilling
2005-07-13 19:11:55 UTC
Permalink
In article <***@o13g2000cwo.googlegroups.com>, Ed Kyle
says...
Post by Ed Kyle
Post by The Apprentice
I'll grant that the SRB has an excellent reliability record, except for
the astronauts it killed on Challenger.
SRB didn't kill the STS-51L crew. By most accounts,
they survived the initial breakup all the way down
to impact with Atlantic. What killed them was NASA
bean counting that decided, back in the early 1970's,
that an escape system cost too much.
What sort of escape system do you imagine would have
saved the Challenger crew? And what is your evidence
that such a system was considered and then discarded
on cost grounds?

The shuttle can be and at times has been fitted with
escape systems, but escape systems providing coverage
over only a fraction of the flight profile. While the
solids are burning, you stay with the shuttle or you
die. No matter how many beans NASA allocates to the
escape system design committe.

The proposed CEV designs seem somewhat more amenable
to robust escape systems, and it is not *completely*
ridiculous to imagine a CEV escape capsule flying clear
of a doomed SRB. Not that I'd want to be the engineer
designing nor the astronaut testing that one...

With Shuttle, I don't think that option was never on the
table.
--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
****@spock.usc.edu * for success" *
*661-951-9107 or 661-275-6795 * -58th Rule of Acquisition *
Pat Flannery
2005-07-14 01:43:58 UTC
Permalink
Post by John Schilling
What sort of escape system do you imagine would have
saved the Challenger crew? And what is your evidence
that such a system was considered and then discarded
on cost grounds?
Originally, the Shuttle was to have burn-through sensors on the SRBs and
twin solid fueled rockets mounted on the orbiter to blast it free from
the stack in case of a problem. The system got dumped due to cost and
weight.

Pat
Ed Kyle
2005-07-14 03:34:19 UTC
Permalink
Post by John Schilling
says...
Post by Ed Kyle
Post by The Apprentice
I'll grant that the SRB has an excellent reliability record, except for
the astronauts it killed on Challenger.
SRB didn't kill the STS-51L crew. By most accounts,
they survived the initial breakup all the way down
to impact with Atlantic. What killed them was NASA
bean counting that decided, back in the early 1970's,
that an escape system cost too much.
What sort of escape system do you imagine would have
saved the Challenger crew? And what is your evidence
that such a system was considered and then discarded
on cost grounds?
Dennis Jenkins "Space Shuttle ... through STS-75"
(1996), Page 105. As part of the Phase B study,
circa 1970-71, potential contractors evaluated
crew escape options. The only viable alternative
was a seperable crew module, but the design was
rejected because it would have raised orbiter
development costs by almost $300 million. This
concept was revisited in later years, after SRBs
were selected, and rejected again (Page 282) due
to "cost and weight impacts".

- Ed Kyle
Douglas Holmes
2005-07-13 10:17:11 UTC
Permalink
Post by Ed Kyle
Post by Douglas Holmes
Post by Ed Kyle
Post by The Apprentice
OK, here's my "If I were Griffin" launch vehicle selections. I'm not a
big fan of the SRB solution
What is wrong with SRB?
They are not safe.
Compared to what?
Just about anything Atlas, Delta and Falcon would all be safer then
this Wiley Coyote creation. This is not a way to get people into orbit
it is the way to kill the manned space program.
At best Wiley leads us right back to where we are now, grounded.
Post by Ed Kyle
A more reliable vehicle makes it easier to
design an escape system that will meet crew
survivability goals (escape systems have their own
odds of success/fail).
I agree more reliable and safer rockets are the way to go.
Atlas, Delta and Falcon are less likely to have a non-survivable failure.
Even if one does fail you still have two other rockets.
The Stick grounds the whole program and maybe kills it.

Atlas and Delta are available now. Test flights could begin now.
The Stick with a lot of luck might be ready for testing in 2010.
In 2008 when the CEV is ready for its first test flight if you use
the stick there will be no way to launch it into to space.
Ed Kyle
2005-07-13 22:05:36 UTC
Permalink
Post by Douglas Holmes
Post by Ed Kyle
Post by Douglas Holmes
Post by Ed Kyle
Post by The Apprentice
OK, here's my "If I were Griffin" launch vehicle selections. I'm not a
big fan of the SRB solution
What is wrong with SRB?
They are not safe.
Compared to what?
Just about anything Atlas, Delta and Falcon would all be safer then
this Wiley Coyote creation. This is not a way to get people into orbit
it is the way to kill the manned space program.
At best Wiley leads us right back to where we are now, grounded.
Post by Ed Kyle
A more reliable vehicle makes it easier to
design an escape system that will meet crew
survivability goals (escape systems have their own
odds of success/fail).
I agree more reliable and safer rockets are the way to go.
Atlas, Delta and Falcon are less likely to have a non-survivable failure.
Just because unsurvivable failure modes are a
smaller proportion of total failures on liquid
rockets than on solid rockets doesn't answer
the question. Liquids fail more often than
solids, so the question to ask is which system
type will, over the life of the program, produce
the lowest number of unsurvivable failures.
More than one study has answered "solid".

- Ed Kyle
Paul F. Dietz
2005-07-13 00:01:01 UTC
Permalink
Post by Ed Kyle
What is wrong with SRB?
If it fails you likely kill the crew.

Paul
Ed Kyle
2005-07-13 04:36:58 UTC
Permalink
Post by Paul F. Dietz
Post by Ed Kyle
What is wrong with SRB?
If it fails you likely kill the crew.
SAIC did a risk assessment for Thiokol that
predicted otherwise - that an escape system
could render at least 80% of SRB failures
crew-survivable. The flight record shows
that SRB failures occur much less often
(perhaps half as often or less) than liquid
booster failures.

- Ed Kyle
George William Herbert
2005-07-13 06:31:04 UTC
Permalink
Post by Ed Kyle
Post by Paul F. Dietz
Post by Ed Kyle
What is wrong with SRB?
If it fails you likely kill the crew.
SAIC did a risk assessment for Thiokol that
predicted otherwise - that an escape system
could render at least 80% of SRB failures
crew-survivable. The flight record shows
that SRB failures occur much less often
(perhaps half as often or less) than liquid
booster failures.
Right, but that was because most SRB failures are due
to mechanisms which are "soft" in either launcher category.

The fact that SRBs sometimes explosively dissassemble
in a manner not seen in flight liquid stages in some
time does even the risk playing field some.


-george william herbert
***@retro.com
Tom Cuddihy
2005-07-13 16:18:29 UTC
Permalink
Post by George William Herbert
Post by Ed Kyle
Post by Paul F. Dietz
Post by Ed Kyle
What is wrong with SRB?
If it fails you likely kill the crew.
SAIC did a risk assessment for Thiokol that
predicted otherwise - that an escape system
could render at least 80% of SRB failures
crew-survivable. The flight record shows
that SRB failures occur much less often
(perhaps half as often or less) than liquid
booster failures.
Right, but that was because most SRB failures are due
to mechanisms which are "soft" in either launcher category.
The fact that SRBs sometimes explosively dissassemble
in a manner not seen in flight liquid stages in some
time does even the risk playing field some.
-george william herbert
It's doubtful an SRB would 'explosively disassemble' in the manner of a
normal strap-on solid booster. If a massive failure happened, it would
likely involve only one segment of the 4 segment SRB, resulting largely
in thrust termination, unless the failure happened directly on the top
of the pressure vessel--in which case it probably is a bad day for the
crew.

cuddihy
Derek Lyons
2005-07-13 18:01:28 UTC
Permalink
Post by Tom Cuddihy
It's doubtful an SRB would 'explosively disassemble' in the manner of a
normal strap-on solid booster. If a massive failure happened, it would
likely involve only one segment of the 4 segment SRB, resulting largely
in thrust termination,
You live in a dream world.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
Pat Flannery
2005-07-13 20:09:48 UTC
Permalink
Post by Derek Lyons
Post by Tom Cuddihy
It's doubtful an SRB would 'explosively disassemble' in the manner of a
normal strap-on solid booster. If a massive failure happened, it would
likely involve only one segment of the 4 segment SRB, resulting largely
in thrust termination,
You live in a dream world.
D.
No, that's very likely what would happen. Thiokol did a intentional SRB
casing failure to see what would occur- the case of the segment
separated in a longitudinal crack that was limited to that particular
segment of the SRB, and did not spread to the segments above or below it.
As we discussed a while back, the Titan III's SRBs were originally
intended to have a abort system that vented the casing at its top into
an outward facing vent on the SRB nose cone. The sudden loss in pressure
inside the SRB tended to snuff out its combustion upon venting. This was
for the rocket's intended use as a Dyna-Soar/MOL booster. As to whether
a crack in a SRB segment would create enough of a pressure drop to stop
combustion is a good question; but the casing of the SRB should stay
together in one piece.

Pat
Derek Lyons
2005-07-13 21:01:20 UTC
Permalink
Post by Pat Flannery
Post by Derek Lyons
Post by Tom Cuddihy
It's doubtful an SRB would 'explosively disassemble' in the manner of a
normal strap-on solid booster. If a massive failure happened, it would
likely involve only one segment of the 4 segment SRB, resulting largely
in thrust termination,
You live in a dream world.
D.
No, that's very likely what would happen. Thiokol did a intentional SRB
casing failure to see what would occur- the case of the segment
separated in a longitudinal crack that was limited to that particular
segment of the SRB, and did not spread to the segments above or below it.
ROTFLMAO. And a massive thrust *sideways* as the propellant vents
through the crack (tumbling the stack at best (the Stick/other SDLV),
or possibly tearing the SRB from the ET (other SDLV) or directing a
massive blowtorch at the ET (other SDLV), will result in nothing more
than thrust termination?
Post by Pat Flannery
As we discussed a while back, the Titan III's SRBs were originally
intended to have a abort system that vented the casing at its top into
an outward facing vent on the SRB nose cone. The sudden loss in pressure
inside the SRB tended to snuff out its combustion upon venting.
And enormous loads are imposed on the stack in the process (which is
why thrust termination wasn't used on Shuttle). It takes a lot of
weight to resist these loads and careful design to ensure that all the
seperation events happen in the right order and at the right time.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
Pat Flannery
2005-07-14 02:10:21 UTC
Permalink
Post by Derek Lyons
ROTFLMAO. And a massive thrust *sideways* as the propellant vents
through the crack (tumbling the stack at best (the Stick/other SDLV),
or possibly tearing the SRB from the ET (other SDLV) or directing a
massive blowtorch at the ET (other SDLV), will result in nothing more
than thrust termination?
That's what you have the escape tower for; the escape tower can be set
up to automatically fire if it senses a problem in the SRB. (does anyone
have data on how long the Apollo LES took to work from fault detection
till escape motor firing? I haven't been able to find info on the
specifics.)
In the case of Challenger, the SRB kept happily flying along with the
hole in its side and flame venting out of it until range safety
destroyed it. The thing is so heavy that it would take a lot of thrust
to get it up to a high rate of of direction change per second, and a
hole in the side isn't a very good shape for efficiently generating
thrust, like the engine nozzle does.
Any side thrust would have a lot of inertia to overcome, and with luck
the escape tower would fire around the time the vehicle deviated a few
degrees from its intended orientation, like it does on Soyuz. (which led
to the strange unmanned aborted launch accident where they forgot to
shut off the escape system and its gyro detected the rotation of the
Earth and interpreted it as the rocket starting to topple over.) If
the side thrust is severe enough it will probably cause the second stage
to structurally fail, and that would at least be one way of separating
the CEV from the stick, although certainly not the preferable one. :-)
Post by Derek Lyons
Post by Pat Flannery
As we discussed a while back, the Titan III's SRBs were originally
intended to have a abort system that vented the casing at its top into
an outward facing vent on the SRB nose cone. The sudden loss in pressure
inside the SRB tended to snuff out its combustion upon venting.
And enormous loads are imposed on the stack in the process (which is
why thrust termination wasn't used on Shuttle). It takes a lot of
weight to resist these loads and careful design to ensure that all the
seperation events happen in the right order and at the right time.
If you're horizontally stacking, it's a whole other ball of wax than if
everything is sitting one-on-top-of-the-other.
Having the SRBs venting in close proximity to the fragile orbiter and
very lightly built ET could be a real mess.
Having whatever is going wrong happening around forty feet or so behind
you at least gives you some chance.

Pat
George William Herbert
2005-07-13 21:30:26 UTC
Permalink
Post by Pat Flannery
Post by Derek Lyons
Post by Tom Cuddihy
It's doubtful an SRB would 'explosively disassemble' in the manner of a
normal strap-on solid booster. If a massive failure happened, it would
likely involve only one segment of the 4 segment SRB, resulting largely
in thrust termination,
You live in a dream world.
No, that's very likely what would happen. Thiokol did a intentional SRB
casing failure to see what would occur- the case of the segment
separated in a longitudinal crack that was limited to that particular
segment of the SRB, and did not spread to the segments above or below it.
Pat...

There's a hole in the side of a mountain where there used to be
a test stand for the Titan IVA SRB units. One of those, segmented
solid boosters, exploded some years back and blew the test stand
and the rock it was sitting on to kingdom come. Had there been
a liquid hydrogen stage and a capsule sitting on top of that
booster, the people would almost certainly not have survived
the shockwave passage through the capsule. An escape tower
would not have had time to act.

Truly catastrophic high order SRB failues are not unheard of.
SRBs gently leaking instead of blowing themselves to bits is
in fact the rare failure mode.

That there exist structural failure modes which don't
cause high order detonation is not in debate. The question
is, are there failure modes where the result is a loud
bang, or not. And we have extensive historical evidence
of the answer to that question being yes.


-george william herbert
***@retro.com / ***@venturerspace.com
Pat Flannery
2005-07-14 02:42:11 UTC
Permalink
Post by George William Herbert
Pat...
There's a hole in the side of a mountain where there used to be
a test stand for the Titan IVA SRB units. One of those, segmented
solid boosters, exploded some years back and blew the test stand
and the rock it was sitting on to kingdom come. Had there been
a liquid hydrogen stage and a capsule sitting on top of that
booster, the people would almost certainly not have survived
the shockwave passage through the capsule. An escape tower
would not have had time to act.
All SRBs are not created equal.
1.) We overbuilt the Shuttle SRBs with that failure mode in mind, and
knowing that it was going to be used on a manned vehicle without a
escape system; whatever else one can hypothesize about failure modes of
the SRB, they have had 216 firings with one complete failure; and in
that case the failure mode was benign enough that the LES could easily
have separated the CEV before there was a real problem with vehicle
breakup.
2.) The SRB redesign that occurred as a result of that accident makes
its reoccurrence far less likely.
3.) The Stick's design eliminates the "twang" problem that the
asymmetrical stacking of the Shuttle caused to the SRB field joints;
they are under far less strain in this design than it the Shuttle.
It could always be that we have just been incredibly lucky with the SRB,
and that one will explode on the next launch, but at the moment the SRB
is the most reliable large rocket stage on the face of the earth, based
not on theoretical mathematics, but actual use for over twenty years.
Delta 4 Heavy and Atlas V are both far from proven systems.
I know it's as far from being technologically "sweet" as it's possible
to get, but it does do its job.
Post by George William Herbert
Truly catastrophic high order SRB failues are not unheard of.
SRBs gently leaking instead of blowing themselves to bits is
in fact the rare failure mode.
Titan IV SRB and a Shuttle SRB are very different pieces of equipment-
you might as well compare the F-1 engine and the H-1 engine; they are
both liquid fueled engines, but their scale is very different and one
had a lot more work put into it's design.
Looking at the models in front of me, it appears that you could fit an
entire Titan II/Gemini into a Shuttle SRB casing.
Post by George William Herbert
That there exist structural failure modes which don't
cause high order detonation is not in debate. The question
is, are there failure modes where the result is a loud
bang, or not. And we have extensive historical evidence
of the answer to that question being yes.
Haven't had a Shuttle SRB go "bang" yet though, and it's been over
twenty years.

Pat
George William Herbert
2005-07-14 05:30:51 UTC
Permalink
Post by Pat Flannery
Post by George William Herbert
Pat...
There's a hole in the side of a mountain where there used to be
a test stand for the Titan IVA SRB units. One of those, segmented
solid boosters, exploded some years back and blew the test stand
and the rock it was sitting on to kingdom come. Had there been
a liquid hydrogen stage and a capsule sitting on top of that
booster, the people would almost certainly not have survived
the shockwave passage through the capsule. An escape tower
would not have had time to act.
All SRBs are not created equal.
True, however...
Post by Pat Flannery
1.) We overbuilt the Shuttle SRBs with that failure mode in mind,
A. That SRB failure happened after the RSRM was designed, and 20 years
after the original Shuttle SRB was designed.

B. Shuttle's SRBs haven't got that much higher a safety margin.

C. It's probably not practical to build that much safety margin
into a launcher... the Titan IV ASRM that blew was on its way
to astronomical overpressures when it ruptured at right around
its predicted burst pressure. Choking the gas flow partway
down the SRB grain is a short trip to a bad day.
Post by Pat Flannery
and
knowing that it was going to be used on a manned vehicle without a
escape system; whatever else one can hypothesize about failure modes of
the SRB, they have had 216 firings with one complete failure; and in
that case the failure mode was benign enough that the LES could easily
have separated the CEV before there was a real problem with vehicle
breakup.
None of which indicates that its odds of catastrophic dissassembly
are necessarily much better than 1/217 or so.

I don't think they're nearly that high; but purely from a historical
standpoint, the number of 'oops, we've never seen that before'
catastrophic SRB failures argues that all of design, assembly,
and flight hold new and exciting ways for them to discover their
inherent ability to rapidly release their high energy content.

A combination of engineering analysis, test, and flight results
tells us that the RSRM is a good motor. But it's not possible
for the best technologically possible solid rocket motor today
to zero the odds of CATO due to unforseen gotcha. And if it
CATOs badly, the crew are going to get killed, period.

What are the real odds? There isn't enough info to establish
the risk definitively. I would say, as a reasonable outer bound,
no further out than 1/1000. And possibly much closer to 1/250.
Historical evidence is that no SRB program has proven immune to
nasty suprises, and the total catastrophic loss rate of large SRBs
(segmented or not) is statistically significant. Even if we
grant that RSRM is a good SRB, it's still a SRB, and CATOs
remain within the predicted future risk envelope for SRBs.
Period.

Is 1/1000 an acceptable risk? Is 1/250 an acceptable risk?
These are separate questions. I think most astronauts will
feel that they're in a reasonable ballpark (STS is still
worse than those). Future commercial astronauts may not agree.
Those are separate questions, though, from assessing the risk
of CATO.


-george william herbert
***@retro.com
Reed Snellenberger
2005-07-14 07:04:57 UTC
Permalink
Post by George William Herbert
What are the real odds? There isn't enough info to establish
the risk definitively. I would say, as a reasonable outer bound,
no further out than 1/1000. And possibly much closer to 1/250.
Historical evidence is that no SRB program has proven immune to
nasty suprises, and the total catastrophic loss rate of large SRBs
(segmented or not) is statistically significant. Even if we
grant that RSRM is a good SRB, it's still a SRB, and CATOs
remain within the predicted future risk envelope for SRBs.
Period.
Pretty thought-provoking post -- thanks...

A couple of questions come to mind...

(1) Has a timeline ever been published for any of the Titan III/IV SRM
incidents? I've seen video of the Vandenburg explosion and although it
seems instantaneous, I'm sure it took a finite amount of time to go from
initiation to fireball. Assuming a similar time for the SRB would give
some kind of lower bound on how quickly any crew escape system would need
to react... assuming a sensor could detect the onset of the problem
(pressure sensor, break wires in the case, etc).

(2) Although there hasn't been much incentive in the past, has there been
any effort to develop an SRM with "blow-out panels" or something similar
to moderate the severity of an incident? It would obviously need to work
in a range that provided a reasonable margin over the normal operating
pressures (plus any normal transients), but "opened" at something less
than the case failure pressure. I imagine, however, that the propellant
is going to distribute the internal pressure in an upset over a wider
area of the case wall than if it were a less rubbery material, so the
panels would be difficult to design and would require some significant
testing.
Post by George William Herbert
Is 1/1000 an acceptable risk? Is 1/250 an acceptable risk?
These are separate questions. I think most astronauts will
feel that they're in a reasonable ballpark (STS is still
worse than those). Future commercial astronauts may not agree.
Those are separate questions, though, from assessing the risk
of CATO.
An optimist would point out that the Stick would at least reduce the
*existing* risk of a catastrophic SRB failure by half over that of the
Shuttle -- and possibly by a little more since (as someone pointed out
earlier) you're eliminating the "twang" that the Shuttle SRB undergoes
today.
--
I was punching a text message into my | Reed Snellenberger
phone yesterday and thought, "they need | GPG KeyID: 5A978843
to make a phone that you can just talk | rsnellenberger
into." Major Thomb | -at-houston.rr.com
Pat Flannery
2005-07-14 14:24:01 UTC
Permalink
Post by Reed Snellenberger
(2) Although there hasn't been much incentive in the past, has there been
any effort to develop an SRM with "blow-out panels" or something similar
to moderate the severity of an incident?
The Titan III SRM was first designed when Titan III was seen as a manned
carrier rocket for the Manned Orbiting Laboratory (MOL) and X-20
Dyna-Soar spaceplane. Because SRMs were looked at askance from a safety
point of view at the time (some thing's never change, do they?) they
were designed with the ability to be able to terminate thrust via having
a blow-off panel at the top of their fuel grain that would allow the
exhaust to vent from the SRM into a pair of dump ducts mounted on the
SRM's nose cone that pointed ninety degrees away from the core stage-
they are the circular items on this cutaway:
http://history.nasa.gov/SP-4221/p49.htm
It was found during testing that the rapid drop of internal pressure
inside the fuel grain that resulted in quickly venting it this way
caused it to cease combustion.
After both Dyna-Soar and MOL were canceled the need for a
crew-survivable abort mode for Titan III vanished, and the venting
system was deleted from the design. The original Shuttle SRB design was
going to use a similar system, but due to the vehicles horizontally
stacked arrangement on the ET it was thought to be unworkable (the
blow-off panels and venting gas would go into the orbiter unless you
canted the ones on the orbiter side of the stack outwards- and that
would mean the ones 180 degrees opposite of them would be canted
inwards, and impinge on the ET and destroy it if the system were used.)
From that system they went to burn-through detectors on the SRBs and
solid-fueled abort motors on the orbiter to allow it to separate from
the launch stack while the SRBs were still firing; these in turn were
then deleted in the interests of economy and weight. Which is
unfortunate, as this system could have given Challenger's crew at least
a fighting chance.

Pat
Derek Lyons
2005-07-14 18:21:30 UTC
Permalink
Post by Pat Flannery
It was found during testing that the rapid drop of internal pressure
inside the fuel grain that resulted in quickly venting it this way
caused it to cease combustion.
However, it induced extremely large loads on the stack - careful
design was needed to ensure that all the termination and separation
events happened correctly.

You always lie by omission by leaving that part out.
Post by Pat Flannery
After both Dyna-Soar and MOL were canceled the need for a
crew-survivable abort mode for Titan III vanished, and the venting
system was deleted from the design. The original Shuttle SRB design was
going to use a similar system, but due to the vehicles horizontally
stacked arrangement on the ET it was thought to be unworkable (the
blow-off panels and venting gas would go into the orbiter unless you
canted the ones on the orbiter side of the stack outwards- and that
would mean the ones 180 degrees opposite of them would be canted
While the position of the vent ports was fixable; the great loads
induced by termination were deemed unsurvivable - the orbiter and ET
were too fragile, and strengthening them would take too much weight.

You always lie by omission by leaving that part out.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
Pat Flannery
2005-07-15 15:44:22 UTC
Permalink
Post by Derek Lyons
Post by Pat Flannery
It was found during testing that the rapid drop of internal pressure
inside the fuel grain that resulted in quickly venting it this way
caused it to cease combustion.
However, it induced extremely large loads on the stack - careful
design was needed to ensure that all the termination and separation
events happened correctly.
You always lie by omission by leaving that part out.
If it comes out of both sides simultaneously, the forces are matched in
at least a horizontal aspect.
It it really were going to screw things up, they wouldn't use this for
thrust termination on the upper stages of ICBMs and SLBM's as it would
throw off the accuracy of the warhead bus.
Post by Derek Lyons
While the position of the vent ports was fixable; the great loads
induced by termination were deemed unsurvivable - the orbiter and ET
were too fragile, and strengthening them would take too much weight.
You always lie by omission by leaving that part out.
First off, CEV/stick isn't horizontally stacked, like the Shuttle, but
vertically stacked.
Remember when Challenger blew? That was pretty catastrophic- yet the
crew module came off the top of the orbiter in fairly intact condition.
I could picture an explosion of the SRB tearing the hell out of the
second stage of the Stick, and having the CEV still intact on what
remains, and using its escape tower. The other classic SRM catastrophic
failure was on the Polaris pad launch at the Cape during its
development. In that case, the first stage blew itself all over the
place, but the second stage ignited and started climbing skywards with
the RV simulator nicely intact on top of it until range safety destroyed it.

Pat
Derek Lyons
2005-07-16 16:56:35 UTC
Permalink
Post by Pat Flannery
Post by Derek Lyons
However, it induced extremely large loads on the stack - careful
design was needed to ensure that all the termination and separation
events happened correctly.
You always lie by omission by leaving that part out.
If it comes out of both sides simultaneously, the forces are matched in
at least a horizontal aspect.
Of course that ignores the vertical aspect - non trivial to say the
least.
Post by Pat Flannery
It it really were going to screw things up, they wouldn't use this for
thrust termination on the upper stages of ICBMs and SLBM's as it would
throw off the accuracy of the warhead bus.
If you knew what you were talking about - you'd know why this false.
But you don't, so I'll explain it: The termination ports on an
ICBM/SLBM's aren't used for emergency thrust termination, they are
used for normal termination. This means it's far easier to 'get
ready' for, as it happens above the atmosphere at a reasonably
predictable time. Furthermore, the ports on ICBM/SLBM's are directed
upwards and outwards - the separation hardware and the thrust
termination ports are fired simultaneously. (An option not available
for the Shuttle in the atmosphere - and maybe possible for a Stick.)
This snatches the spent stage clear of the bus with little fuss.
Post by Pat Flannery
Post by Derek Lyons
While the position of the vent ports was fixable; the great loads
induced by termination were deemed unsurvivable - the orbiter and ET
were too fragile, and strengthening them would take too much weight.
You always lie by omission by leaving that part out.
First off, CEV/stick isn't horizontally stacked, like the Shuttle, but
vertically stacked.
Certainly - but you were discussing the Shuttle not the Stick.
Post by Pat Flannery
Remember when Challenger blew? That was pretty catastrophic- yet the
crew module came off the top of the orbiter in fairly intact condition.
ROTFLMAO. 'fairly intact' *chuckle*.
Post by Pat Flannery
I could picture an explosion of the SRB tearing the hell out of the
second stage of the Stick, and having the CEV still intact on what
remains, and using its escape tower.
I can equally picture such an explosion inducing large vertical loads
- and potentially disabling the CEV/escape system. Or tumbling the
upper section.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
Pat Flannery
2005-07-16 17:58:22 UTC
Permalink
Post by Derek Lyons
Post by Pat Flannery
If it comes out of both sides simultaneously, the forces are matched in
at least a horizontal aspect.
Of course that ignores the vertical aspect - non trivial to say the
least.
If the thing completely explodes, the vast majority of the blast and
shrapnel will blow out sideways.
The real problem would be if the top dome on the SRB separated and
headed straight up into the second stage; if that's the case it will
have to get through a J-2 engine and four propellant tank bulkheads
before reaching the CEV itself (plus the LOX and LH2 in the fully fueled
second stage) that should dissipate a lot of its energy, although I can
see it being a fatal situation.
If it's just a sudden loss of thrust, then all that happens is that the
actual G loading on the vehicle suddenly decreases; although atmospheric
drag on the vehicle may cause a minor reverse G effect if thrust
suddenly drops to zero, it probably wont be anything too significant.
The major bad situation that they looked into in the study for the
vehicle: http://www.boom.net/~jake/atk_docs/ATK_Thiokol_SRB.J_2S_PRA.pdf
...was a rupture near the top SRB generates a shockwave that goes up
the side of the vehicle and reaches the CEV; the effect is severe on the
pad, but decreases as the vehicle's speed increases during ascent, and
the airflow around it drives the blast effect backwards. At max Q it
doesn't get beyond the interstage structure, as shown on page 11 of the
report.
In the report they list catastrophic failure of the SRB as a 100% fatal
situation, but note that they are erring on the conservative side, and
that the vehicle's crew may well be able to survive this in some
situations due to the vehicle's ability to abort using its escape tower.
Post by Derek Lyons
Post by Pat Flannery
It it really were going to screw things up, they wouldn't use this for
thrust termination on the upper stages of ICBMs and SLBM's as it would
throw off the accuracy of the warhead bus.
If you knew what you were talking about - you'd know why this false.
But you don't, so I'll explain it: The termination ports on an
ICBM/SLBM's aren't used for emergency thrust termination, they are
used for normal termination. This means it's far easier to 'get
ready' for, as it happens above the atmosphere at a reasonably
predictable time. Furthermore, the ports on ICBM/SLBM's are directed
upwards and outwards - the separation hardware and the thrust
termination ports are fired simultaneously. (An option not available
for the Shuttle in the atmosphere - and maybe possible for a Stick.)
This snatches the spent stage clear of the bus with little fuss.
Post by Pat Flannery
Post by Derek Lyons
While the position of the vent ports was fixable; the great loads
induced by termination were deemed unsurvivable - the orbiter and ET
were too fragile, and strengthening them would take too much weight.
You always lie by omission by leaving that part out.
First off, CEV/stick isn't horizontally stacked, like the Shuttle, but
vertically stacked.
Certainly - but you were discussing the Shuttle not the Stick.
No, I'm talking about the Stick, and why it's okay to use a SRB as its
first stage. I never liked the Shuttle's horizontal stacking because any
failure of the SRB would almost certainly doom the crew, due to the
proximity of the SRBs to the Orbiter/ET, and the inability to separate
the Orbiter from the stack during SRB burn. A catastrophic SRB failure
on the Shuttle would reduce the ET to scrap metal and blow one entire
wing off the orbiter (at the very least) in under a second.
With the SRB CEV booster whatever goes wrong happens behind you, not
beside you, and that's a major improvement from the safety point of view.
Post by Derek Lyons
Post by Pat Flannery
Remember when Challenger blew? That was pretty catastrophic- yet the
crew module came off the top of the orbiter in fairly intact condition.
ROTFLMAO. 'fairly intact' *chuckle*.
Intact enough that it fell into the ocean in one piece with the crew
still alive (and conscious immediately after the orbiter break-up, as
the activation of the PEAPS shows) inside of it, even though it was
never intended to be separated from the Orbiter in this manner.
Post by Derek Lyons
Post by Pat Flannery
I could picture an explosion of the SRB tearing the hell out of the
second stage of the Stick, and having the CEV still intact on what
remains, and using its escape tower.
I can equally picture such an explosion inducing large vertical loads
- and potentially disabling the CEV/escape system. Or tumbling the
upper section.
Theoretically, you should be able to have a completely automatic
fast-acting sensor activation system for the CEV LES that fires it in
under one second if trouble develops with the SRB. If the whole SRB case
is going to rupture it's going to be due to a catastrophic pressure
increase inside the casing, and the sensors would pick that up as it's
starting to occur.
The best indication that that's not going to happen very often is that
we've fired 216 SRBs and had one that leaked, but never one that
exploded. And as Stalin said "Quantity has a quality all of its own".

Pat
Pat Flannery
2005-07-14 13:40:24 UTC
Permalink
Post by George William Herbert
True, however...
Post by Pat Flannery
1.) We overbuilt the Shuttle SRBs with that failure mode in mind,
A. That SRB failure happened after the RSRM was designed, and 20 years
after the original Shuttle SRB was designed.
B. Shuttle's SRBs haven't got that much higher a safety margin.
C. It's probably not practical to build that much safety margin
into a launcher... the Titan IV ASRM that blew was on its way
to astronomical overpressures when it ruptured at right around
its predicted burst pressure. Choking the gas flow partway
down the SRB grain is a short trip to a bad day.
I don't see what you are driving at here- the Titan IV SRB and the
Shuttle SRB are two different systems (and built by two different
contractors BTW)- they are both solid-fueled rockets, but I don't know
why one's failings should be related to the reliability of the other.
Post by George William Herbert
Post by Pat Flannery
knowing that it was going to be used on a manned vehicle without a
escape system; whatever else one can hypothesize about failure modes of
the SRB, they have had 216 firings with one complete failure; and in
that case the failure mode was benign enough that the LES could easily
have separated the CEV before there was a real problem with vehicle
breakup.
None of which indicates that its odds of catastrophic dissassembly
are necessarily much better than 1/217 or so.
I don't think they're nearly that high; but purely from a historical
standpoint, the number of 'oops, we've never seen that before'
catastrophic SRB failures argues that all of design, assembly,
and flight hold new and exciting ways for them to discover their
inherent ability to rapidly release their high energy content.
A combination of engineering analysis, test, and flight results
tells us that the RSRM is a good motor. But it's not possible
for the best technologically possible solid rocket motor today
to zero the odds of CATO due to unforseen gotcha. And if it
CATOs badly, the crew are going to get killed, period.
How many total flights do you envision for the Stick/CEV before it's
retired? Without a space station to take crew to (I think we are going
to gracefully bow out of the ISS in fairly short order) it's mission
becomes wholly related to the Moon and Mars missions, unlike the Soyuz
crew ferry ships. I think that we will probably see forty to fifty CEV
flights total to accomplish those ends (assuming the next administration
doesn't just cancel the whole thing, which I think is very likely), and
with that few flights the odds of catastrophic failure you cite are
probably acceptable.
It should be pointed out that a catastrophic failure wouldn't just
happen out of the blue for no reason; it would mean something in the SRB
wasn't working as it was supposed to- either there was a problem with
the fuel grain, the casing, or the casing's field joints. And that
should be able to be pretty much eliminated with thorough inspection and
strict quality control of the SRB's production and assembly. One nice
aspect of the SRBs is that we get to examine them in detail after they
are recovered; a luxury we don't have with other rocket stages,
including the Titan IV's SRBs.
If you can look things over after it has flown its mission you can spot
anomalies and correct them before you have a catastrophic failure. The
Titan IV SRB blew during testing (as did more than one F-1 engine, IIRC)
and the launch vehicle's in-flight SRB failure on August 2, 1993 was
directly traceable to radial cuts made in the SRB fuel grain's
restrictor that reached the exterior casing when they shouldn't have
had. that's sloppy production, not an inherent design flaw.
Post by George William Herbert
What are the real odds? There isn't enough info to establish
the risk definitively. I would say, as a reasonable outer bound,
no further out than 1/1000. And possibly much closer to 1/250.
Historical evidence is that no SRB program has proven immune to
nasty suprises, and the total catastrophic loss rate of large SRBs
(segmented or not) is statistically significant. Even if we
grant that RSRM is a good SRB, it's still a SRB, and CATOs
remain within the predicted future risk envelope for SRBs.
Period.
Is 1/1000 an acceptable risk?
Yes, I would think that would be a perfectly acceptable risk. It's far
better than the Shuttle's, and we consider that to have an acceptable
risk envelope at the moment. Not that I'd ever climb aboard that damn thing.
Post by George William Herbert
Is 1/250 an acceptable risk?
Borderline, but I'd still say yes- provided you don't intend to make
over 249 flights with it. ;-)
Just kidding. Given the likely flight numbers (and my most likely flight
number is 0) I'd say you could get through the whole program with only
around a 1/4 to 1/8 odds of ever losing a crew to catastrophic SRB
failure during it at 1/250 odds of failure.
Post by George William Herbert
These are separate questions. I think most astronauts will
feel that they're in a reasonable ballpark (STS is still
worse than those). Future commercial astronauts may not agree.
Commercial astronauts on The Stick? I don't think it was ever intended
to do that. That would imply that commercial astronauts were heading to
the Moon or Mars, and that's a long, long, way into the future.

Pat
Rand Simberg
2005-07-14 17:02:39 UTC
Permalink
On Thu, 14 Jul 2005 08:40:24 -0500, in a place far, far away, Pat
Post by Pat Flannery
Commercial astronauts on The Stick? I don't think it was ever intended
to do that. That would imply that commercial astronauts were heading to
the Moon or Mars, and that's a long, long, way into the future.
It's not that long in the future, but no one who wants to get to the
moon affordably will use the Satay, or any hardware that NASA plans to
develop.
Tom Cuddihy
2005-07-14 19:10:23 UTC
Permalink
Post by Rand Simberg
It's not that long in the future,
A thousand years is like a day to God.
Pat Flannery
2005-07-16 06:10:06 UTC
Permalink
Post by Tom Cuddihy
Post by Rand Simberg
It's not that long in the future,
A thousand years is like a day to God.
That explains why Jesus wasn't shown up yet- God has apparently decided
to put the second coming off till the weekend. :-)

Pat
Derek Lyons
2005-07-14 18:16:50 UTC
Permalink
Post by George William Herbert
What are the real odds? There isn't enough info to establish
the risk definitively. I would say, as a reasonable outer bound,
no further out than 1/1000. And possibly much closer to 1/250.
Historical evidence is that no SRB program has proven immune to
nasty suprises, and the total catastrophic loss rate of large SRBs
(segmented or not) is statistically significant.
Which brings up a question I've been pondering for a while now;

Why are space related solids having Very Loud problems - while the
SLBM/Minuteman programs don't seem to be? It can't be the size or the
joints as we've had problems with the little ones too.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
Tom Cuddihy
2005-07-14 19:18:47 UTC
Permalink
Post by Derek Lyons
Post by George William Herbert
What are the real odds? There isn't enough info to establish
the risk definitively. I would say, as a reasonable outer bound,
no further out than 1/1000. And possibly much closer to 1/250.
Historical evidence is that no SRB program has proven immune to
nasty suprises, and the total catastrophic loss rate of large SRBs
(segmented or not) is statistically significant.
Which brings up a question I've been pondering for a while now;
Why are space related solids having Very Loud problems - while the
SLBM/Minuteman programs don't seem to be? It can't be the size or the
joints as we've had problems with the little ones too.
Derek, dont believe,
don't believe the hype.

If you'll notice, THE space related solid incident everyone keeps
referring to about happened more than 10 years ago. Challenger was 19
years ago. SLBMs completed major development way more than 10 years
ago, plus their failures were kept under wraps during the cold war.

There isn't a problem with space related solids any more than there is
with SLBMs. And with the SRSMs, there is clear and convincing evidence
that the recovery and inspection process has drastically increased SRSM
reliability. The number of post-launch anomalies is down to less than a
quarter of what it was immediately post-Challenger, and has been stable
and continuing to decrease ever since.
Thiokal has the motor pretty much nailed down.

cuddihy
Derek Lyons
2005-07-14 22:42:45 UTC
Permalink
Post by Derek Lyons
Post by George William Herbert
What are the real odds? There isn't enough info to establish
the risk definitively. I would say, as a reasonable outer bound,
no further out than 1/1000. And possibly much closer to 1/250.
Historical evidence is that no SRB program has proven immune to
nasty suprises, and the total catastrophic loss rate of large SRBs
(segmented or not) is statistically significant.
Which brings up a question I've been pondering for a while now;
Why are space related solids having Very Loud problems - while the
SLBM/Minuteman programs don't seem to be? It can't be the size or the
joints as we've had problems with the little ones too.
Derek, dont believe, don't believe the hype.
If you'll notice, THE space related solid incident everyone keeps
referring to about happened more than 10 years ago. Challenger was 19
years ago.
There is this little thing called a pattern Tom - and the pattern is
that space related solid rocket motors keep having Very Loud problems.
SLBMs completed major development way more than 10 years
ago, plus their failures were kept under wraps during the cold war.
As with Jorge - you need to learn who the fuck you are lecturing you
little twit. I was *in* the SLBM program for ten years - I've *read*
the classified reports on the failures. And there are launches *other*
than PEM (R&D to the rest of the world) - I.E. there are routine test
launches. (There were 6 D5 launchs in 2002 *alone*.)

I don't know about the rest of the places you hang out - but here on
s.s.*, there are a bunch of people who've actually been places and
done things - not mentally masturbating fanboys like yourself. (Not
that we don't have other like you mind - but it's a bad assumption to
make that the guy on the other end of your newsreader knows as little
as you do.)
There isn't a problem with space related solids any more than there is
with SLBMs.
Which is why SLBM's haven't been going kaboom on a routine basis - and
space related solids have, on a depressingly routine basis.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
Jim Davis
2005-07-15 00:08:33 UTC
Permalink
...you need to learn who the fuck you are lecturing you
little twit.
...there are a bunch of people who've actually been
places and done things - not mentally masturbating fanboys like
yourself.
-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
Derek, that temperance resolution just isn't doing the job. :-)

Jim Davis
Rand Simberg
2005-07-15 03:11:32 UTC
Permalink
On 15 Jul 2005 00:08:33 GMT, in a place far, far away, Jim Davis
Post by Jim Davis
...you need to learn who the fuck you are lecturing you
little twit.
...there are a bunch of people who've actually been
places and done things - not mentally masturbating fanboys like
yourself.
-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
Derek, that temperance resolution just isn't doing the job. :-)
Hey, resolutions are made to be broken.

That's why I don't bother.
Derek Lyons
2005-07-16 17:00:35 UTC
Permalink
Post by Jim Davis
...you need to learn who the fuck you are lecturing you
little twit.
...there are a bunch of people who've actually been
places and done things - not mentally masturbating fanboys like
yourself.
-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
Derek, that temperance resolution just isn't doing the job. :-)
It's been doing pretty well so far - this idiot is the first I've gone
off on in a *long* time. His handwaving ignorance and tendency to
lecture folks (Along with his condescening attitude - trying to
correct *me* on SLBM history?) just finally blew my fuse.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
Tom Cuddihy
2005-07-15 00:23:32 UTC
Permalink
Post by Derek Lyons
Post by Derek Lyons
Post by George William Herbert
What are the real odds? There isn't enough info to establish
the risk definitively. I would say, as a reasonable outer bound,
no further out than 1/1000. And possibly much closer to 1/250.
Historical evidence is that no SRB program has proven immune to
nasty suprises, and the total catastrophic loss rate of large SRBs
(segmented or not) is statistically significant.
Which brings up a question I've been pondering for a while now;
Why are space related solids having Very Loud problems - while the
SLBM/Minuteman programs don't seem to be? It can't be the size or the
joints as we've had problems with the little ones too.
Derek, dont believe, don't believe the hype.
If you'll notice, THE space related solid incident everyone keeps
referring to about happened more than 10 years ago. Challenger was 19
years ago.
There is this little thing called a pattern Tom - and the pattern is
that space related solid rocket motors keep having Very Loud problems.
SLBMs completed major development way more than 10 years
ago, plus their failures were kept under wraps during the cold war.
As with Jorge - you need to learn who the fuck you are lecturing you
little twit. I was *in* the SLBM program for ten years - I've *read*
the classified reports on the failures. And there are launches *other*
than PEM (R&D to the rest of the world) - I.E. there are routine test
launches. (There were 6 D5 launchs in 2002 *alone*.)
I don't know about the rest of the places you hang out - but here on
s.s.*, there are a bunch of people who've actually been places and
done things - not mentally masturbating fanboys like yourself. (Not
that we don't have other like you mind - but it's a bad assumption to
make that the guy on the other end of your newsreader knows as little
as you do.)
There isn't a problem with space related solids any more than there is
with SLBMs.
Which is why SLBM's haven't been going kaboom on a routine basis - and
space related solids have, on a depressingly routine basis.
D.
--
Touch-twice life. Eat. Drink. Laugh.
-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
Tom Cuddihy
2005-07-15 01:02:45 UTC
Permalink
Post by Derek Lyons
Post by Derek Lyons
Post by George William Herbert
What are the real odds? There isn't enough info to establish
the risk definitively. I would say, as a reasonable outer bound,
no further out than 1/1000. And possibly much closer to 1/250.
Historical evidence is that no SRB program has proven immune to
nasty suprises, and the total catastrophic loss rate of large SRBs
(segmented or not) is statistically significant.
Which brings up a question I've been pondering for a while now;
Why are space related solids having Very Loud problems - while the
SLBM/Minuteman programs don't seem to be? It can't be the size or the
joints as we've had problems with the little ones too.
Derek, dont believe, don't believe the hype.
If you'll notice, THE space related solid incident everyone keeps
referring to about happened more than 10 years ago. Challenger was 19
years ago.
There is this little thing called a pattern Tom - and the pattern is
that space related solid rocket motors keep having Very Loud problems.
SLBMs completed major development way more than 10 years
ago, plus their failures were kept under wraps during the cold war.
As with Jorge - you need to learn who the fuck you are lecturing you
little twit.
I suggest you let Jorge speak for Jorge, you pompous ass. It's not like
usenet tags have 'biography' attached to them.
Post by Derek Lyons
I was *in* the SLBM program for ten years - I've *read*
the classified reports on the failures.
I don't pretend to be anything other than what I am, a student studying
space systems eng for the first time. In a few years I'll be working on
acquisition of some of those national systems. You, on the other hand,
are coming off as a disgruntled former civil servant staking a position
about solid rockets on info that only you have--and something you
certainly didn't mention in your last post.
Post by Derek Lyons
And there are launches *other*
than PEM (R&D to the rest of the world) - I.E. there are routine test
launches. (There were 6 D5 launchs in 2002 *alone*.)
I don't know about the rest of the places you hang out - but here on
s.s.*, there are a bunch of people who've actually been places and
done things - not mentally masturbating fanboys like yourself. (Not
thanks for being my first usenet flamer. You do a pretty good
impression of a mentally masturbating geekwad yourself. What's sad is
that you're doing that at however old you must be given what your
experience is.
Post by Derek Lyons
that we don't have other like you mind - but it's a bad assumption to
make that the guy on the other end of your newsreader knows as little
as you do.)
There isn't a problem with space related solids any more than there is
with SLBMs.
Which is why SLBM's haven't been going kaboom on a routine basis - and
space related solids have, on a depressingly routine basis.
D.
--
Touch-twice life. Eat. Drink. Laugh.
-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
/\
/ \
and that just puts the cherry on the cup cake.
Tom Cuddihy
2005-07-15 01:14:15 UTC
Permalink
Post by Derek Lyons
I was *in* the SLBM program for ten years - I've *read*
the classified reports on the failures.
BTW, it just registered what that means...you're a boomer fag! You
absolute fake! trying to pass off time on a boomer as time in a missile
program! Give me an f'ing break.
Rand Simberg
2005-07-15 04:16:27 UTC
Permalink
On 14 Jul 2005 18:14:15 -0700, in a place far, far away, "Tom Cuddihy"
Post by Tom Cuddihy
Post by Derek Lyons
I was *in* the SLBM program for ten years - I've *read*
the classified reports on the failures.
BTW, it just registered what that means...you're a boomer fag! You
absolute fake! trying to pass off time on a boomer as time in a missile
program! Give me an f'ing break.
Tom, do you really think that this lends any credence to your
arguments, given your admission that your still soaking wet behind the
ears?
Rand Simberg
2005-07-15 04:17:35 UTC
Permalink
On Fri, 15 Jul 2005 04:16:27 GMT, in a place far, far away,
Post by Rand Simberg
Tom, do you really think that this lends any credence to your
arguments, given your admission that your still soaking wet behind the
ears?
Sorry, that should be "you're."

That's why I like blogs--a lot easier to edit...
Tom Cuddihy
2005-07-15 05:51:02 UTC
Permalink
Post by Rand Simberg
On 14 Jul 2005 18:14:15 -0700, in a place far, far away, "Tom Cuddihy"
Post by Tom Cuddihy
Post by Derek Lyons
I was *in* the SLBM program for ten years - I've *read*
the classified reports on the failures.
BTW, it just registered what that means...you're a boomer fag! You
absolute fake! trying to pass off time on a boomer as time in a missile
program! Give me an f'ing break.
Tom, do you really think that this lends any credence to your
arguments, given your admission that your still soaking wet behind the
ears?
I'm not the one trying to pass myself off as an expert. Driving circles
under the water and turning away from anything that looks like it might
be a contact on the AVSDU, while reading 7 page incident reports about
Polaris missiles misfired during the early 80s hardly makes Derek into
a solid rocket motor expert, and he damn well knows it. I wouldn't
claim to be an expert on the Tomahawk booster just because I read a few
incident reports about mishandled missiles while I was the A weps. And
here he is trying to pass himself off as some NASA expert like,
apparently Jorge is. Most of all, he pissed me off by being an asshole
for no reason.

Not to mention his largely passive missile experience bearing on my
point above that the main solid motor failure being talked about was
from a LONG time ago.
If he had actually worked on propulsion, and not just stood watch or
been a misile officer dept head after 6 months at SOAC, he would have
said so.

the 'boomer fag' thing is jsut a little repartee between a fast boat
guy and a...boomer baby.
Derek Lyons
2005-07-16 21:43:17 UTC
Permalink
Post by Tom Cuddihy
I'm not the one trying to pass myself off as an expert. Driving circles
under the water and turning away from anything that looks like it might
be a contact on the AVSDU, while reading 7 page incident reports about
Polaris missiles misfired during the early 80s hardly makes Derek into
a solid rocket motor expert, and he damn well knows it.
Did I pass myself off as a solid motor expert? No I did not. Did I
pass myself off as knowledgeable about SLBM's? Yes I did and do.
(Mostly because I've done far more than just read incident reports -
I've also widely read the literature.)
Post by Tom Cuddihy
I wouldn't claim to be an expert on the Tomahawk booster just because
I read a few incident reports about mishandled missiles while I was
the A weps. And here he is trying to pass himself off as some NASA expert
like, apparently Jorge is. Most of all, he pissed me off by being an
asshole for no reason.
I'm being an asshole because of your utterly ignorant pronouncements
about solid motor safety.
Post by Tom Cuddihy
Not to mention his largely passive missile experience bearing on my
point above that the main solid motor failure being talked about was
from a LONG time ago.
Anyone who claims that because an incident was a 'long time ago' is
meaningless *despite* ongoing failures and indications of problems is
an ignorant child.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
Derek Lyons
2005-07-16 21:49:04 UTC
Permalink
Post by Tom Cuddihy
I don't pretend to be anything other than what I am, a student studying
space systems eng for the first time.
A student at about the 8th grade level - a knowledgeable engineer
wouldn't make the idiot pronouncements you continue to make.
Post by Tom Cuddihy
You, on the other hand, are coming off as a disgruntled former civil
servant staking a position about solid rockets on info that only you have
Nope. All information easily available in the open literature - if
you have the wit to search it out and brainpower to comprehend it.
(To wit: Claiming that SLBM development was ten years in the past -
when it's trivially provable that launches are ongoing.)

And don't think I failed to notice that you avoided addressing a
single one of my factual points - concentrating on other matters
instead. I also note you fail to reply to Ed and George when *they*
show you wrong as well - concentrating on other matters instead.

That says much about you.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
George William Herbert
2005-07-14 22:47:07 UTC
Permalink
Post by Tom Cuddihy
Post by Derek Lyons
Post by George William Herbert
What are the real odds? There isn't enough info to establish
the risk definitively. I would say, as a reasonable outer bound,
no further out than 1/1000. And possibly much closer to 1/250.
Historical evidence is that no SRB program has proven immune to
nasty suprises, and the total catastrophic loss rate of large SRBs
(segmented or not) is statistically significant.
Which brings up a question I've been pondering for a while now;
Why are space related solids having Very Loud problems - while the
SLBM/Minuteman programs don't seem to be? It can't be the size or the
joints as we've had problems with the little ones too.
Derek, dont believe,
don't believe the hype.
If you'll notice, THE space related solid incident everyone keeps
referring to about happened more than 10 years ago.
There has been far more than just one single spectacular failure
of a solid booster in recent history. Just off the top of my head....

Jan 17, 1997: GEM on a Delta 7925 suffers catastrophic case
failure and the vehicle explodes shortly after liftoff
at the Cape.

Aug 2, 1993: Titan IV SRM suffers propellent grain failure
and explosion 101 sec after liftoff from Vandenberg.

Apr 18, 1986: Titan 34D SRM suffers case burnthrough and
catastrophic failure and explosion 8.5 sec after liftoff
from Vandenberg.

And then there was the Titan IV SRMU pad explosion we're
talking about on April 1, 1991, where the booster blew
up its test pad and the mountain side in a qualification
(non-flight) test.

And, of course, Challenger, and 11 other non-fatal
joint/seal/O-ring failures in prior Shuttle flights...

As the Delta, Titan 34D, and Titan IV flight failures show,
motors with extensive flight experience, and thought to be
"good solid motors", have had catastrophic accidents in
flight.

Even excluding the qualification test as statistically relevant
to flight risks, it is a true statement that most medium-large
SRBs have had flight failures after the design was in production
and "mature". RSRM is an exception to the rule, but there is a
difference between noting that it's one of the few designs
to not have had a failure, and asserting that lack of a failure
to date means that it will never have one.

Hubris kills.


-george william herbert
***@retro.com
Ed Kyle
2005-07-15 14:55:37 UTC
Permalink
Post by George William Herbert
There has been far more than just one single spectacular failure
of a solid booster in recent history. Just off the top of my head....
Jan 17, 1997: GEM on a Delta 7925 suffers catastrophic case
failure and the vehicle explodes shortly after liftoff
at the Cape.
Aug 2, 1993: Titan IV SRM suffers propellent grain failure
and explosion 101 sec after liftoff from Vandenberg.
Apr 18, 1986: Titan 34D SRM suffers case burnthrough and
catastrophic failure and explosion 8.5 sec after liftoff
from Vandenberg.
And then there was the Titan IV SRMU pad explosion we're
talking about on April 1, 1991, where the booster blew
up its test pad and the mountain side in a qualification
(non-flight) test.
And, of course, Challenger, and 11 other non-fatal
joint/seal/O-ring failures in prior Shuttle flights...
The April 1 ATK-SAIC reliability study
"http://www.boom.net/~jake/atk_ docs/ATK_Thiokol_SRB.J_2S_PRA. pdf"
implies that most of these incidents could have been
survivable because they did not involve propellant
detonation, but case burst with propellant dispersal.
A CEV might be able to survive the pressure waves
produced by these incidents, at least according to
some smart guys at SAIC who will never have to ride
atop an SRB. They predicted that only 1 out of
3,145 crews launched by an SRB/J2S equipped with an
effective escape system would be lost.

Personally, I don't trust this probabilistic risk
assessment stuff, because it always seems to
underestimate the real risks. SAIC says that SRB
failures of all types will happen only about one
time in every 3,000 launches. I think that most
engineers who have been around these machines for
any length of time would say that this one in
3,000 stuff is bonafide hogwash.

I think that the only safe assumption to make is
that SRBs will fail in the future roughly as often
as they have failed in the past - something like
one failure in every 200 to 250 SRB burns. But
some of these failures are going to be survivable.
The big question is how many. If three out of
four are survivable, then the SRB loss of crew
probability could approach 1 in 1,000.

But then there is the upper stage to worry about,
and staging events, etc. Not all upper stage
failures, even benign early shutdowns, are
survivable. Crews could survive the initial event,
only to be lost during or after their descent. My
guess is that upper stage failure survival rates
are going to be only somewhat better than SRB rates.
The net result would be a total launch vehicle loss
of crew probability of something better than
1 in 500.

This doesn't sound superior, but I think that an
EELV, when you consider that it has more complex
components and more components altogether so that
the base failure rate is higher than SRB, would
provide roughly the same crew survival results.

- Ed Kyle
Ed Kyle
2005-07-14 19:32:30 UTC
Permalink
Post by Derek Lyons
Which brings up a question I've been pondering for a while now;
Why are space related solids having Very Loud problems - while the
SLBM/Minuteman programs don't seem to be? It can't be the size or the
joints as we've had problems with the little ones too.
Perhaps it is simply that the military solids
have progressed much further through the learning
curve than space solids. There have been almost
850 Minuteman test flights (more than any other
type of large U.S. rocket), and many static tests
of Minuteman motors, for example. They've been
flying them continuously since 1959. By contrast,
there have only been 122 solid-boosted Titan
launches since the first in 1965 (244 SRM or SRMU
flights) and 113 shuttle flights (226 SRB flights)
since 1981. The Minuteman program has experienced
34 failures, according to astronautix.com, (failure
mode is not reported, so it is likely that only a
few of these were motor-related failures), but half
of these failures had occurred by the end of *1962*.

But there have been Minuteman failures since. The
most recent was in May 2000. Another one blew up,
or was blown up, spectacularly at low altitude in
June 1998.

- Ed Kyle
Ed Kyle
2005-07-14 20:34:12 UTC
Permalink
Post by Ed Kyle
Post by Derek Lyons
Which brings up a question I've been pondering for a while now;
Why are space related solids having Very Loud problems - while the
SLBM/Minuteman programs don't seem to be? It can't be the size or the
joints as we've had problems with the little ones too.
Perhaps it is simply that the military solids
have progressed much further through the learning
curve than space solids. There have been almost
850 Minuteman test flights (more than any other
type of large U.S. rocket), and many static tests
of Minuteman motors, for example. They've been
flying them continuously since 1959. By contrast,
there have only been 122 solid-boosted Titan
launches since the first in 1965 (244 SRM or SRMU
flights) and 113 shuttle flights (226 SRB flights)
since 1981. The Minuteman program has experienced
34 failures, according to astronautix.com, (failure
mode is not reported, so it is likely that only a
few of these were motor-related failures), but half
of these failures had occurred by the end of *1962*.
But there have been Minuteman failures since. The
most recent was in May 2000. Another one blew up,
or was blown up, spectacularly at low altitude in
June 1998.
Sorry. That should have been February 1998.
Post by Ed Kyle
- Ed Kyle
John Schilling
2005-07-13 19:31:06 UTC
Permalink
In article <***@o13g2000cwo.googlegroups.com>, Tom Cuddihy
says...
Post by Tom Cuddihy
Post by George William Herbert
Post by Ed Kyle
Post by Paul F. Dietz
Post by Ed Kyle
What is wrong with SRB?
If it fails you likely kill the crew.
SAIC did a risk assessment for Thiokol that
predicted otherwise - that an escape system
could render at least 80% of SRB failures
crew-survivable. The flight record shows
that SRB failures occur much less often
(perhaps half as often or less) than liquid
booster failures.
Right, but that was because most SRB failures are due
to mechanisms which are "soft" in either launcher category.
The fact that SRBs sometimes explosively dissassemble
in a manner not seen in flight liquid stages in some
time does even the risk playing field some.
It's doubtful an SRB would 'explosively disassemble' in the manner of a
normal strap-on solid booster. If a massive failure happened, it would
likely involve only one segment of the 4 segment SRB, resulting largely
in thrust termination...
And possibly termination of a whole lot of other things.

Does the phrase "Titan IV SRMU" ring a bell? Because I can walk outside
and gaze in awe at the bit of local hard-rock landscape that got rearranged
by that little "thrust termination event".

Large segmented solid rocket motors *do* have catastrophic failure modes,
including high-order detonations, and even if we do magically confine the
failure to one segment, any one segment packs more energy than a Grand
Slam bomb.
--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
****@spock.usc.edu * for success" *
*661-951-9107 or 661-275-6795 * -58th Rule of Acquisition *
Ian Stirling
2005-07-14 20:19:29 UTC
Permalink
The Apprentice <***@galaxy.org> wrote:

Anyone else see the thread title, and immediately think of Thomas Covenants
work.
Quite an appropriate acronym.
Tom Cuddihy
2005-07-15 18:27:32 UTC
Permalink
Post by Ian Stirling
Anyone else see the thread title, and immediately think of Thomas Covenants
work.
Quite an appropriate acronym.
lol. "Visual Survey of Extremities?" Is that an implication that the
space program is leprous and decaying?


I'm sure Stephen R Donaldson would be proud.
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