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| Fred J. McCall... |
 Posted: Thu Nov 05, 2009 2:48 pm |
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"Jeff Findley" <jeff.findley at (no spam) ugs.nojunk.com> wrote:
:
:"Damon Hill" <damon1SIX1 at (no spam) comcast.netnet> wrote in message
:news:Xns9CBA719AC458Fdamon161attbicom at (no spam) 127.0.0.1...
:> "Jeff Findley" <jeff.findley at (no spam) ugs.nojunk.com> wrote in
:> news:26918$4af31b41$927a2cda$10992 at (no spam) FUSE.NET:
:>
:>>
:>> "Brian Thorn" <bthorn64 at (no spam) suddenlink.net> wrote in message
:>> news:rhb4f5he1cge0sogl8e7t4pag7r752bd1m at (no spam) 4ax.com...
:>>> On Wed, 4 Nov 2009 11:16:19 -0500, "Jeff Findley"
:>>> <jeff.findley at (no spam) ugs.nojunk.com> wrote:
:>>>
:>>>
:>>>>Depens on how reliable a single engine is, then you can use
:>>>>statistics to figure out the chance of engine failure. Even so,
:>>>>liquid engine failures are usually benign. With nine engines on each
:>>>>core, you simply shut the malfunctioning engine and continue the
:>>>>mission.
:>>>
:>>> And hope the wiring didn't get botched between the controllers and
:>>> all those engines, resulting in a good engine being turned off and
:>>> the bad one going kablooey.
:>>
:>> That particular Russian failure ought to have been caught during
:>> pre-launch testing, but they were in a race to beat the Americans and
:>> corners were cut in the name of time. Hopefully SpaceX is more detail
:>> oriented than the Russians were during the space race.
:>
:> Hasn't that scenario already been tested on the ground with Falcon 9?
:> Engines will normally be shut down near the end of the first stage
:> burn to limit acceleration and shutdown transients.
:>
:> I'd like to think communications between the flight controller and
:> individual engine controllers will more sophisticated than the N-1
:> apparently was.
:
:I don't think the "sophistication" of an engine controller matters if the
:guys assembling the rocket stage don't plug the right connectors into the
:right sockets. Getting your "wires crossed" in this manner can have
:disastrous consequences, so you would want to run tests on the ground before
:you launch the thing.
:
What if they don't connect the brake lines on your car to the right
things? What if the flight controls on that jetliner you're riding
are reversed?
Some things are just preposterous to worry about.
--
"Rule Number One for Slayers - Don't die."
-- Buffy, the Vampire Slayer |
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| Derek Lyons... |
| Posted: Thu Nov 05, 2009 3:57 pm |
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"Jeff Findley" <jeff.findley at (no spam) ugs.nojunk.com> wrote:
[quote]
"Brian Thorn" <bthorn64 at (no spam) suddenlink.net> wrote in message
news:rhb4f5he1cge0sogl8e7t4pag7r752bd1m at (no spam) 4ax.com...
On Wed, 4 Nov 2009 11:16:19 -0500, "Jeff Findley"
jeff.findley at (no spam) ugs.nojunk.com> wrote:
Depens on how reliable a single engine is, then you can use statistics to
figure out the chance of engine failure. Even so, liquid engine failures
are usually benign. With nine engines on each core, you simply shut the
malfunctioning engine and continue the mission.
And hope the wiring didn't get botched between the controllers and all
those engines, resulting in a good engine being turned off and the bad
one going kablooey.
That particular Russian failure ought to have been caught during pre-launch
testing, but they were in a race to beat the Americans and corners were cut
in the name of time. Hopefully SpaceX is more detail oriented than the
Russians were during the space race.
[/quote]
Yet, the detail oriented Americans made an equally significant wiring
error on AS-502.
D.
--
Touch-twice life. Eat. Drink. Laugh.
http://derekl1963.livejournal.com/
-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL |
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| Jeff Findley... |
| Posted: Thu Nov 05, 2009 4:08 pm |
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"Fred J. McCall" <fjmccall at (no spam) gmail.com> wrote in message
news:iua6f5pohgpbbipo387nj98ahdle4lh6s9 at (no spam) 4ax.com...
[quote]"Jeff Findley" <jeff.findley at (no spam) ugs.nojunk.com> wrote:
:I don't think the "sophistication" of an engine controller matters if the
:guys assembling the rocket stage don't plug the right connectors into the
:right sockets. Getting your "wires crossed" in this manner can have
:disastrous consequences, so you would want to run tests on the ground
before
:you launch the thing.
:
What if they don't connect the brake lines on your car to the right
things?
[/quote]
That doesn't seem to directly relate to complex wiring harnesses on
expendable vehicles which are hand built due to very low production rates.
[quote]What if the flight controls on that jetliner you're riding
are reversed?
[/quote]
Every time I've flown with a pilot friend of mine, he runs through a
pre-flight check which would catch this problem. Neglecting to perform
basic pre-flight checks is especially foolish when you've never flown that
particular aircraft before (which is the case for every launch of an
expendable vehicle).
[quote]Some things are just preposterous to worry about.
[/quote]
Hope is not a satisfactory substitute for a quality assurance program.
Jeff
--
"Take heart amid the deepening gloom
that your dog is finally getting enough cheese" - Deteriorata - National
Lampoon |
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| Jeff Findley... |
| Posted: Thu Nov 05, 2009 4:25 pm |
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"Derek Lyons" <fairwater at (no spam) gmail.com> wrote in message
news:4af33bc0.176222796 at (no spam) news.supernews.com...
[quote]"Jeff Findley" <jeff.findley at (no spam) ugs.nojunk.com> wrote:
"Brian Thorn" <bthorn64 at (no spam) suddenlink.net> wrote in message
news:rhb4f5he1cge0sogl8e7t4pag7r752bd1m at (no spam) 4ax.com...
On Wed, 4 Nov 2009 11:16:19 -0500, "Jeff Findley"
jeff.findley at (no spam) ugs.nojunk.com> wrote:
Depens on how reliable a single engine is, then you can use statistics
to
figure out the chance of engine failure. Even so, liquid engine
failures
are usually benign. With nine engines on each core, you simply shut the
malfunctioning engine and continue the mission.
And hope the wiring didn't get botched between the controllers and all
those engines, resulting in a good engine being turned off and the bad
one going kablooey.
That particular Russian failure ought to have been caught during
pre-launch
testing, but they were in a race to beat the Americans and corners were
cut
in the name of time. Hopefully SpaceX is more detail oriented than the
Russians were during the space race.
Yet, the detail oriented Americans made an equally significant wiring
error on AS-502.
[/quote]
True, and hopefully you learn from such early failures (this was only the
second, unmanned, flight test of the Saturn V).
Hand wired expendable launch vehicles such as these really ought to be
better tested before they're flown. Unfortunately, there are some things
that you simply can't test without flying. Every flight is the first flight
for an expendable, so infant mortality problems such as these become
especially troublesome.
Jeff
--
"Take heart amid the deepening gloom
that your dog is finally getting enough cheese" - Deteriorata - National
Lampoon |
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| Fred J. McCall... |
| Posted: Thu Nov 05, 2009 5:04 pm |
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Guest
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"Jeff Findley" <jeff.findley at (no spam) ugs.nojunk.com> wrote:
:
:"Fred J. McCall" <fjmccall at (no spam) gmail.com> wrote in message
:news:iua6f5pohgpbbipo387nj98ahdle4lh6s9 at (no spam) 4ax.com...
:> "Jeff Findley" <jeff.findley at (no spam) ugs.nojunk.com> wrote:
:> :I don't think the "sophistication" of an engine controller matters if the
:> :guys assembling the rocket stage don't plug the right connectors into the
:> :right sockets. Getting your "wires crossed" in this manner can have
:> :disastrous consequences, so you would want to run tests on the ground
:> before
:> :you launch the thing.
:> :
:>
:> What if they don't connect the brake lines on your car to the right
:> things?
:
:That doesn't seem to directly relate to complex wiring harnesses on
:expendable vehicles which are hand built due to very low production rates.
:
Doesn't it? Why not?
:> What if the flight controls on that jetliner you're riding
:> are reversed?
:
:Every time I've flown with a pilot friend of mine, he runs through a
:pre-flight check which would catch this problem. Neglecting to perform
:basic pre-flight checks is especially foolish when you've never flown that
:particular aircraft before (which is the case for every launch of an
:expendable vehicle).
:
Yeah, but there are lots of problems a 'stir' *won't* uncover.
:> Some things are just preposterous to worry about.
:
:Hope is not a satisfactory substitute for a quality assurance program.
:
Nobody said it was.
--
"Insisting on perfect safety is for people who don't have the balls to
live in the real world."
-- Mary Shafer, NASA Dryden |
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| Brian Thorn... |
| Posted: Thu Nov 05, 2009 9:00 pm |
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On Thu, 5 Nov 2009 13:36:49 -0500, "Jeff Findley"
<jeff.findley at (no spam) ugs.nojunk.com> wrote:
[quote]And hope the wiring didn't get botched between the controllers and all
those engines, resulting in a good engine being turned off and the bad
one going kablooey.
That particular Russian failure ought to have been caught during pre-launch
testing, but they were in a race to beat the Americans and corners were cut
in the name of time. Hopefully SpaceX is more detail oriented than the
Russians were during the space race.
[/quote]
It almost happened to Saturn V AS-502 also, the bad engine shut down
on its own, fortunately. And Martin-Marietta botched the wiring on
Commercial Titan III because they got the single payload/dual payload
setup reversed.
Brian |
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| Pat Flannery... |
| Posted: Mon Nov 09, 2009 3:52 pm |
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Dave U. Random wrote:
[quote]27 engines vs. 30 engines (First stage)
What are the chances of the Falcon 9 blowing up too?
[/quote]
I'd by concerned about that many engines generating some pretty involved
harmonic effects.
Pat |
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| Pat Flannery... |
| Posted: Mon Nov 09, 2009 4:03 pm |
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Jochem Huhmann wrote:
[quote]
Additionally the Russians did never test the N-1 first stage prior to
launch, while SpaceX already did a full test for the F-9 first stage.
This is not to say that the Falcon 9 (Heavy) can't fail, but it has a
much higher chance not to fail than the N-1.
[/quote]
All four N=1 failures were due to different causes, not some fundamental
flaw in the engines.
Pat |
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| Pat Flannery... |
| Posted: Mon Nov 09, 2009 4:06 pm |
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Anthony Frost wrote:
[quote]
There's also a considerable difference between feeding 30 engines from
a single set of tanks and feeding each group of nine engines from its
own set of tanks. The more complex the plumbing, the more potential
problems there are.
[/quote]
N-1 plumbing was a complex and heavy mess with so many long pipes being
involved that it was almost begging for some pipe or weld seam to fail
under launch vibration.
Pat |
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| Pat Flannery... |
| Posted: Mon Nov 09, 2009 4:17 pm |
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Jeff Findley wrote:
[quote]And hope the wiring didn't get botched between the controllers and all
those engines, resulting in a good engine being turned off and the bad
one going kablooey.
That particular Russian failure ought to have been caught during pre-launch
testing, but they were in a race to beat the Americans and corners were cut
in the name of time. Hopefully SpaceX is more detail oriented than the
Russians were during the space race.
[/quote]
The joys of KORD, a "reliability-improving" system that seemed almost
designed to cause a rocket to fail:
http://catless.ncl.ac.uk/Risks/21.53.html#subj4
Pat |
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| Pat Flannery... |
| Posted: Mon Nov 09, 2009 4:29 pm |
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Brian Thorn wrote:
[quote]
It almost happened to Saturn V AS-502 also, the bad engine shut down
on its own, fortunately. And Martin-Marietta botched the wiring on
Commercial Titan III because they got the single payload/dual payload
setup reversed.
[/quote]
Ariane V failed during its first launch when the guidance system
reverted into a ground test configuration during flight.
Pat |
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| Jochem Huhmann... |
| Posted: Mon Nov 09, 2009 6:38 pm |
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Guest
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Pat Flannery <flanner at (no spam) daktel.com> writes:
[quote]Jochem Huhmann wrote:
Additionally the Russians did never test the N-1 first stage prior to
launch, while SpaceX already did a full test for the F-9 first stage.
This is not to say that the Falcon 9 (Heavy) can't fail, but it has a
much higher chance not to fail than the N-1.
All four N=1 failures were due to different causes, not some fundamental
flaw in the engines.
[/quote]
But all were due to a flaw in the first stage which could have been
caught with full testing. They did never (to my knowlegde) a full
vibration test, a fuel flow test or (god forbid) a test with all engines
running for the full duration of the first stage burn.
All of that has been done with the Falcon 9 first stage, though. All
engines running with a full first stage attached for the full duration
of a real launch. This still leaves the aerodynamic effects out, but I
would say that there's about an order of magnitude more confidence in
the thing than in the N-1 now.
Jochem
--
"A designer knows he has arrived at perfection not when there is no
longer anything to add, but when there is no longer anything to take away."
- Antoine de Saint-Exupery |
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| OM... |
| Posted: Wed Nov 11, 2009 2:32 am |
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On Tue, 10 Nov 2009 00:38:45 +0100, Jochem Huhmann <joh at (no spam) gmx.net>
wrote:
[quote]But all were due to a flaw in the first stage which could have been
caught with full testing. They did never (to my knowlegde) a full
vibration test, a fuel flow test or (god forbid) a test with all engines
running for the full duration of the first stage burn.
[/quote]
....Correct. About the only static testing they did was individual
engines, and possibly 2-3 engines in cluster. The issue was secrecy,
in that either a static test of the full 30+ engine cluster and/or a
single-stage launch test could/would have been detected by US spy sats
- which is what happened anyway when they rolled the full stack out to
the launch site either the first or second time, there's some debate
about which pad checkout was caught and labled as "TT-5".
OM
--
]=====================================[
] OMBlog - http://www.io.com/~o_m/omworld [
] Let's face it: Sometimes you *need* [
] an obnoxious opinion in your day! [
]=====================================[ |
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| Me... |
| Posted: Wed Nov 11, 2009 5:26 am |
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On Nov 11, 2:32 am, OM <om at (no spam) all_trolls_must_DIE.com> wrote:
The issue was secrecy,
[quote]in that either a static test of the full 30+ engine cluster and/or a
single-stage launch test could/would have been detected by US spy sats
- which is what happened anyway when they rolled the full stack out to
[/quote]
It has nothing to do with secrecy. It was money and time, which they
didn't have. |
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| Jeff Findley... |
| Posted: Wed Nov 11, 2009 10:11 am |
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Guest
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"OM" <om at (no spam) all_trolls_must_DIE.com> wrote in message
news:9vpkf51gnj79euigtu1afm863q8nftmnmd at (no spam) 4ax.com...
[quote]On Tue, 10 Nov 2009 00:38:45 +0100, Jochem Huhmann <joh at (no spam) gmx.net
wrote:
But all were due to a flaw in the first stage which could have been
caught with full testing. They did never (to my knowlegde) a full
vibration test, a fuel flow test or (god forbid) a test with all engines
running for the full duration of the first stage burn.
...Correct. About the only static testing they did was individual
engines, and possibly 2-3 engines in cluster. The issue was secrecy,
in that either a static test of the full 30+ engine cluster and/or a
single-stage launch test could/would have been detected by US spy sats
- which is what happened anyway when they rolled the full stack out to
the launch site either the first or second time, there's some debate
about which pad checkout was caught and labled as "TT-5".
[/quote]
That and I don't think the Soviet Union was ever fully invested in the moon
race. It wasn't important enough for them to focus all of their efforts on
that single space program. They had several different programs going on
internally, so their efforts were always divided. Even their space station
work in the 70's suffered from this. Duplication of effort was rampant in
their space program and I'm not sure it ever completely ended.
Jeff
--
"Take heart amid the deepening gloom
that your dog is finally getting enough cheese" - Deteriorata - National
Lampoon |
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