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#260
by
bombay
on 21 Jun, 2007 23:57
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Would someone be kind enough to please explain to me what constitutes a launch failure.
Between the Delta IV heavy that successfully placed 3 satellites into the wrong orbit and the AV009 that successfully came up short of the desired orbit, the AF and Space & Missile Systems Center, with the support of Boeing (Delta IV launch) and ULA (AV009), appear to be on a quest to redefine what a launch failure is.
It's as if there all in some sort of EELV protection mode.
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#261
by
Rocket Guy
on 22 Jun, 2007 00:17
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bombay - 21/6/2007 7:57 PM
the Delta IV heavy that successfully placed 3 satellites into the wrong orbit
The two small ride-along sats did not enter orbit; they burned up after a suborbital trajectory.
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#262
by
Nick L.
on 22 Jun, 2007 00:30
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bombay - 21/6/2007 7:57 PM
Would someone be kind enough to please explain to me what constitutes a launch failure.
Between the Delta IV heavy that successfully placed 3 satellites into the wrong orbit and the AV009 that successfully came up short of the desired orbit, the AF and Space & Missile Systems Center, with the support of Boeing (Delta IV launch) and ULA (AV009), appear to be on a quest to redefine what a launch failure is.
It's as if there all in some sort of EELV protection mode.
Failure: when it goes BOOM!
But seriously, a failure is when the satellite doesn't get into the right orbit. I don't think anyone, ULA or AF or otherwise, is claiming that either the Delta IV Heavy demo or AV-009 is an unqualified success.
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#263
by
sbt
on 22 Jun, 2007 00:31
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Note that they said "not intended to infer that the mission was a failure". It's quite possible for the launcher to underperform and the Satellites mission be achieved.
It then becomes a moot point as how large an 'underperformance' is a failure - 10 secs short? 3 secs? 1 sec? 0.1 sec? 0.001 sec? There is a grey area where pre-planned margins are invoked, systems fail over to redundant spares, planned alternative mission profiles used etc.
In the end I think I would class this as a LV failure as recovery from the shortfall depended on the design of the spacecraft being launched. Unless there is a minimum corrective manoeuvre capability specified for all payloads on the LV type this could have resulted in a mission failure for a spacecraft of arbitrary design.
Personal opinion only BTW and I expect to be corrected by the professionals on this.
Rick
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#264
by
yinzer
on 22 Jun, 2007 01:33
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There's no solid answer. Some possible definitions might be "payload lit on fire and dropped into the pacific", or "higher delta-V to final orbit than specified in the launch contract paperwork", or "whatever makes the insurance company have to pay out."
That said, something clearly went wrong on AV-009, and any potential customer will want to know what that was and how Lockheed intends to fix it. But I'd imagine that until more information comes out most potential customers will be less concerned by NROL-30 than they are by NSS-8, for instance.
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#265
by
Antares
on 22 Jun, 2007 04:41
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The solid generically-accurate answer is 3 standard deviations below nominal, unless as in the case of Falcon 1.2 the prepublished mission objectives were something other than a target orbit. I never saw prepublished objectives for Heavy Demo that would get it out of being a failure. Yinzer is right in that contracts are usually written to define a success as a maximum amount of delta-V to make the mission orbit, and for commercial sats insurance policies are redeemed when a certain amount of lifetime is lost as a result of launch vehicle performance (or, on orbit, premature solar panel degradation or XIPS malfs, etc.).
The payload contract for the AC-70 launch granted mission success at liftoff. Too bad the second stage couldn't start because it was iced up.
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#266
by
edkyle99
on 30 Jun, 2007 23:37
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#267
by
Rocket Guy
on 30 Jun, 2007 23:41
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They issued a press release on this two or three days ago, which is where they got that information. I had it but I did not save it; not sure where online it is. It also indicated the next launch would not be delayed as a result or that they would at least press on assuming it would be cleared.
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#268
by
Rocket Guy
on 30 Jun, 2007 23:44
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#269
by
edkyle99
on 01 Jul, 2007 00:12
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My first guess would be that a problem occurred with a (or the) liquid hydrogen vent valve during the coast phase. That valve would not "pop" open until the latter portion of the coast, which would be consistent with the apparent small fuel loss. Otherwise, the only other valves that I could think might be on the stage would be the engine inlet valve, the fuel inlet shutoff valve, a fill and drain valve, and maybe a propellant utilization valve. If any of those valves failed to close, the fuel loss would be substantial.
- Ed Kyle
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#270
by
edkyle99
on 21 Jul, 2007 14:41
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The Air Force now says it was a leaky hydrogen propellant valve in the Pratt & Whitney Rocketdyne RL10 Centaur upper stage engine that caused the AV-009 Atlas failure on June 15, 2007. Craig Covault of Aviation Week reported this on July 20.
An ongoing investigation to determine the cause of the failure will delay one Atlas launch by one week at least. RL10 engines power both Atlas V and Delta IV upper stages, and both EELVs are scheduled to fly during the final days of August, so additional delays are possible IMO.
RL-10 engines are equipped with several valves in the liquid hydrogen chain. These include a main fuel pump inlet shutoff valve, a pair of cooldown bleed and pressure relief valves, a thrust controller valve, and a main fuel shutoff valve positioned downstream from the fuel pump. I'm told that the main fuel pump inlet shutoff valve is the most likely mechanism involved in the AV-009 incident, which occurred during the Centaur coast phase prior to the second burn.
http://www.aviationweek.com/aw/blogs/space/index.jsp?plckController=Blog&plckScript=blogScript&plckElementId=blogDest&plckBlogPage=BlogViewPost&plckPostId=Blog%3a04ce340e-4b63-4d23-9695-d49ab661f385Post%3aaab64601-729e-43a2-874c-8579bd530aa9 - Ed Kyle
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#271
by
Nick L.
on 21 Jul, 2007 19:11
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edkyle99 - 21/7/2007 10:41 AM
The Air Force now says it was a leaky hydrogen propellant valve in the Pratt & Whitney Rocketdyne RL10 Centaur upper stage engine that caused the AV-009 Atlas failure on June 15, 2007. Craig Covault of Aviation Week reported this on July 20.
An ongoing investigation to determine the cause of the failure will delay one Atlas launch by one week at least. RL10 engines power both Atlas V and Delta IV upper stages, and both EELVs are scheduled to fly during the final days of August, so additional delays are possible IMO.
RL-10 engines are equipped with several valves in the liquid hydrogen chain. These include a main fuel pump inlet shutoff valve, a pair of cooldown bleed and pressure relief valves, a thrust controller valve, and a main fuel shutoff valve positioned downstream from the fuel pump. I'm told that the main fuel pump inlet shutoff valve is the most likely mechanism involved in the AV-009 incident, which occurred during the Centaur coast phase prior to the second burn.
http://www.aviationweek.com/aw/blogs/space/index.jsp?plckController=Blog&plckScript=blogScript&plckElementId=blogDest&plckBlogPage=BlogViewPost&plckPostId=Blog%3a04ce340e-4b63-4d23-9695-d49ab661f385Post%3aaab64601-729e-43a2-874c-8579bd530aa9
- Ed Kyle
Do you know if these valves are the same on the Delta IV RL10B-2 as on the Atlas RL10A-4? This could really throw a wrench in the works.
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#272
by
Jim
on 21 Jul, 2007 20:26
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They know it and both Delta and Atlas are working it
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#273
by
edkyle99
on 07 Aug, 2007 14:26
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#274
by
Jim
on 07 Aug, 2007 14:46
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The D-IVH delays are not due to AV-009
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#275
by
Analyst
on 07 Aug, 2007 15:00
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I wonder what the secrets are. Is it to much for Boeing or LM to say they are working a problem with the payload, with second stage engine etc. Heck, they (want to) offer these vehicles commercially. Even the Russians are more open. And what do you lose with being a little more open? Now people guess and come the false conclusions, then they will know. The first is better for reputation, something not bad in this business.
Analyst
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#276
by
Jim
on 07 Aug, 2007 15:19
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Analyst - 7/8/2007 11:00 AM
I wonder what the secrets are. Is it to much for Boeing or LM to say
Analyst
Yes, because they aren't anymore. It is ULA. But also the USAF does the PR for their own flights
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#277
by
Analyst
on 07 Aug, 2007 16:41
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Jim - 7/8/2007 5:19 PM
Analyst - 7/8/2007 11:00 AM
I wonder what the secrets are. Is it to much for Boeing or LM to say
Analyst
Yes, because they aren't anymore. It is ULA. But also the USAF does the PR for their own flights
So I replace Boeing or LM by ULA and USAF.
Analyst
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#278
by
Jim
on 07 Aug, 2007 17:00
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What little info the USAF provides is more than in the past, which was none. The USAF doesn't need nor wants the extra PR.
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#279
by
oscar71
on 07 Aug, 2007 17:04
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Jim - 7/8/2007 10:19 AM
Analyst - 7/8/2007 11:00 AM
I wonder what the secrets are. Is it to much for Boeing or LM to say
Analyst
Yes, because they aren't anymore. It is ULA. But also the USAF does the PR for their own flights
So why does the article mention "Lockheed Martin Commercial Launch Services (LMCLS)" and not ULA?
