Pad damage

What's NASA said about the damage?

On Tue, 03 Jun 2008 00:24:08 -0500, Pat Flannery
wrote:

If the subsurface material that the pad is built on has shifted or
slumped from age and repeated launchings, then the whole pad may be
dangerous to use without major reconstruction, pretty much from the
ground up.

....Ok, if it's not a leaky pipe, then there's only one other thing it
could be. Gophers.

OM
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] Let's face it: Sometimes you *need* [
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wrote:
The solid propellant doesn't detonate and if a chunk came out, it
would mean there is a problem with the SRM. Impossible with the
liquids.


The SRB propellant is pretty flexible anyway (something along the lines
of a pencil eraser), so it wouldn't be prone to shedding a chunk.
Early solid fuels could suffer fractures in their grains due to
temperature variations, like taking them into very cold or hot
environments, but that ceased to be a problem several decades ago with
improved fuel mixtures.
(This led to the odd heaters mounted inside of the cylinder that
surrounded the Soviet Frog-1 artillery rocket as it rode around on its
tank chassis in the cold Russian winter:
http://www.fas.org/man/dod-101/sys/m...frog-1_002.jpg
It may also account for why early Falcon AAMs were only carried
internally by interceptors that operated at high and cold altitudes,
though I'm not sure about that.)
I'll tell you one thing though... if you want a _lot_ of thrust out of a
solid fueled rocket engine, fire one with cracks in its fuel
grain...you'll be amazed at the short burn time and high thrust. I tried
out a ignition system on one of my homemade ones that involved a soda
straw full of black powder inserted up the bore in the grain, and it
shattered the grain when the black powder went off...and converted a
planned burn time of around three seconds at around one hundred pounds
thrust into a burn time of around one second at around five hundred to
seven hundred pounds thrust - that shot out a exhaust flame around
twenty feet long which set fire to the tree is it was being fired
nozzle-up under. It was buried in the ground when this happened, and
thank God the casing held... as otherwise it probably would have gone
off like a landmine. Considering that the casing was a iron plumbing
pipe this would probably not have been good from a shrapnel viewpoint...
particularly since the test was going on around twenty feet from my
childhood house. :-D

Pat

Pat Flannery wrote in
dakotatelephone:



OM wrote:
...And weren't you also noting that the downlink audio had a
significant vibration to it? I'm now wondering if there was more to it
now, Brian.


Some sort of resonance between the acoustic exhaust frequencies of the
SRBs or SSMEs?
If there was damaged caused, you'd expect it to be a lot more likely
that the SRBs would be involved, due to their far greater acoustic
shockwave output.
Although you can explain the shed concrete panels in the interior of the
flame trench (via the zipper effect after one shed in the high velocity
exhaust flow from the SRBs), those shifted panels on the ramp that
surrounds the flame trench proper are more worrying.
If the subsurface material that the pad is built on has shifted or
slumped from age and repeated launchings, then the whole pad may be
dangerous to use without major reconstruction, pretty much from the
ground up.
That would be very time-consuming and expensive.

Yes, possibly. Now imagine this scenario with a full-up Ares V at
around 10 million pounds of thrust...

--Damon

The downlink audio on the launch is always slightly different I find. it
would be hard to say if any acoustic differences wer due to placement of
microphones, which I understand are a fair way away an very directional,
or debris.

Things tend to age and so I'd suggest that the launch may just have been
the proverbial straw as there was some underlying damage that could not be
seen on the surface.

Brian

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Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
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"OM" wrote in message
...
On Mon, 02 Jun 2008 22:22:50 GMT, "Brian Gaff"
wrote:

So then, what is the cause. Is it subsidence? Sounds like some ultrasound
testing might be in order in the trench.

...And weren't you also noting that the downlink audio had a
significant vibration to it? I'm now wondering if there was more to it
now, Brian.

OM
--
]=====================================[
] OMBlog - http://www.io.com/~o_m/omworld [
] Let's face it: Sometimes you *need* [
] an obnoxious opinion in your day! [
]=====================================[

Did all the water sprays actually work correctly do we know.

From the tank point of view, I'd say this is a red herring, myself. The
fact is that this is a new tank and has been made with the mods from the
ground up. What is not known of course is how much of the good performance
of the modified tanks was due to the re application of foam after the mods
being better than the normal application.


I'd have expected a lot more damage to the tank than apparently there was if
the debris from the pad had hit it, likewise with the orbiter of course. One
tiny bit of torn blanket patch is hardly major damage, though one has to
wonder if micro sized debris got into the oms mechanics and upset the back
up striiing later in the ascent.

I doubt anyone will be able to tell for certain till the orbiter gets back.

Brian

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Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
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"Brian Thorn" wrote in message
...
On Mon, 02 Jun 2008 18:11:35 -0500, OM
wrote:

On Mon, 02 Jun 2008 22:22:50 GMT, "Brian Gaff"
wrote:

So then, what is the cause. Is it subsidence? Sounds like some ultrasound
testing might be in order in the trench.

...And weren't you also noting that the downlink audio had a
significant vibration to it? I'm now wondering if there was more to it
now, Brian.

And the disturbing increase in number and size of debris from a Tank
that was supposed to be the "best yet" (but in reality looks to be the
second worst since RTF.)

Related? Probably not, but with NASA seemingly unwilling to
acknowledge that the new Tank gave a far from stellar performance, its
hard to just dismiss the possibility.

Brian

Be interesting to see if the srbs show any signs of damage and they are back
around now I think.


I would not want to chance launching if the pad were unstable, but you would
think that if it were, some cracks would, by now be showing in the top of
it. Water could then get in and freeze assuming low enough temperatures.

I plump for a less severe scenario of some underlying movement of soil etc,
possibly caused by water and drying out cycles or similar, and the
unzipping effect. The sms do fire for a long time before the solids are lit,
long enough to loosen something ready for the shock wave of solid ignition
to pulverise the loose material and lift off turbulence to scatter it far
and wide.

Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"Damon Hill" wrote in message
...
Pat Flannery wrote in
dakotatelephone:



OM wrote:
...And weren't you also noting that the downlink audio had a
significant vibration to it? I'm now wondering if there was more to it
now, Brian.


Some sort of resonance between the acoustic exhaust frequencies of the
SRBs or SSMEs?
If there was damaged caused, you'd expect it to be a lot more likely
that the SRBs would be involved, due to their far greater acoustic
shockwave output.
Although you can explain the shed concrete panels in the interior of the
flame trench (via the zipper effect after one shed in the high velocity
exhaust flow from the SRBs), those shifted panels on the ramp that
surrounds the flame trench proper are more worrying.
If the subsurface material that the pad is built on has shifted or
slumped from age and repeated launchings, then the whole pad may be
dangerous to use without major reconstruction, pretty much from the
ground up.
That would be very time-consuming and expensive.

Yes, possibly. Now imagine this scenario with a full-up Ares V at
around 10 million pounds of thrust...

--Damon

Alan Erskine wrote:
What's NASA said about the damage?


http://www.spaceflightnow.com/shuttl...d3/index3.html
http://www.spaceflightnow.com/shuttl...ad/damage.html

Pat

On Mon, 02 Jun 2008 20:18:07 -0500, Damon Hill
wrote:

Rick Jones wrote in news:g2227b$pdk$1
:

How much can come off an SRB without it being "fatal?" Could a chunk
of propellant have come-loose and detonated somewhere in the tunnel?
How about the liquid propellants?

No. Most likely the pad's aged and deteriorated enough that it's
started to fall apart under the stress. Imagine what a full-up
Ares V might do to it with 10 million pounds or more of thrust...

Way back in the 70's, I had the unique opportunity to walk through
one of those trenches. I don't remember the lining being so clean
appearing; seemed like it was pretty sooty.

I read either on NYTimes.com or BBC.com that some of the blocks were
blown 1800 feet away. Come to think of it, the number was also given
as 550 meters, so it must have been the latter source. Pretty
impressive. Quite the demonstration of the power of this thing. I'm
sure they'll get it fixed up for a few million bucks in time for the
next launch. Probably just an incidental but interesting expense in
the big scheme of things.

Dale

"Pat Flannery" wrote in message
dakotatelephone...


Alan Erskine wrote:
What's NASA said about the damage?

http://www.spaceflightnow.com/shuttl...d3/index3.html
http://www.spaceflightnow.com/shuttl...ad/damage.html

Pat

Thank you, Mr Flannery. If you take a look at the second image from the
second link, it looks like the flame trench itself has been pushed outward,
squashing the concrete panels; like the crumpling seen when one squeezes a
matchbox.