Author Topic: Vulcan VC2S V001 - Peregrine Lander - CCSFS SLC-41 - 8 Jan 2024 (07:18 UTC)  (Read 442494 times)

Offline Newton_V

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i find it highly ironic that despite all the bashing of the BE-4 engine being late, turns out its the tried and proven centaur that ultimately delayed the launch of the vulcan lol ::)
It's a different beast, the 5m.

Offline Apollo-phill

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The dome repair .

Is the top dome ( LH2) welded ?

If so, how easy to remove , strengthen ( extra added panel?) and reweld ?

Was the welding automated or manual ?

Will they examine the lower LOX Dome once inside stage?


Offline edkyle99

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What explosion?  It was a Rapid Unplanned Venting, like popping a balloon.
NFPA 921's definition of an "explosion" (the one I use) is the "sudden conversion of potential energy (chemical or mechanical) into kinetic energy with the production and release of gases under pressure, or the release of gas under pressure". 

That's what happened during the Centaur 5 test.

As for the fix, the in old days they would have added doublers to key points, perhaps as an interim fix until thicker panels could be used to new build stages.  Not sure how ULA will do things.  Manufacturing is different these days.

 - Ed Kyle
« Last Edit: 06/25/2023 12:26 pm by edkyle99 »

Offline WindnWar

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What explosion?  It was a Rapid Unplanned Venting, like popping a balloon.
NFPA 921's definition of an "explosion" (the one I use) is the "sudden conversion of potential energy (chemical or mechanical) into kinetic energy with the production and release of gases under pressure, or the release of gas under pressure". 

That's what happened during the Centaur 5 test.

As for the fix, the in old days they would have added doublers to key points, perhaps as an interim fix until thicker panels could be used to new build stages.  Not sure how ULA will do things.  Manufacturing is different these days.

 - Ed Kyle

I would assume the doublers get welded to the existing weld lines correct? Any risk especially with such thin metal to begin with that it makes those welds more brittle?

Offline Apollo-phill

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Dome repair.

I was asking to try get a " handle " on how long repair/s may take.

I'm fairly certain they'll have to " dryout" tank of any residual liquids/ gas still  inside before any repair operation. That may take a few days.

Was the Centaur tank built
 using "Friction Stir Welding" to form?

I'm thinking they could use plasma cutting to cut through original weld line though ' normal ' torch welding may work ?

Is there a "reverse undo" method for friction stir welding ?

On such a large cylinder object I assume the weld machine is " static " and the dome/tank rotated past work head?

Or do they do manually?

Whatever methods going take a few weeks and, of course, if only one machine will take longer to do the minimum repairs - flight version and test version

Quality control at end process has to be high to ensure over welds 100%

Wish team all success on this


Offline Apollo-phill

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Just researched ULA re Vulcan and Centaur.

Frictional Stir Welding (FSW) is used on both Vulcan 1st stage and Centaur . ULA have a wealth of experience with FSW having used on Delta,Atlas and Shuttle programs.


Offline woods170

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i find it highly ironic that despite all the bashing of the BE-4 engine being late, turns out its the tried and proven centaur that ultimately delayed the launch of the vulcan lol ::)
It's a different beast, the 5m.

In its current form, as it will fly on the first several flights, it is in fact not much different from Centaur III DEC. Only major differences are the different diameter and the improved insulation. But for most other aspects, such as engine layout, RCS, tank pressurization, avionics, etc., it is highly similar to Centaur III DEC.

Offline woods170

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What explosion?  It was a Rapid Unplanned Venting, like popping a balloon.
NFPA 921's definition of an "explosion" (the one I use) is the "sudden conversion of potential energy (chemical or mechanical) into kinetic energy with the production and release of gases under pressure, or the release of gas under pressure". 

That's what happened during the Centaur 5 test.

As for the fix, the in old days they would have added doublers to key points, perhaps as an interim fix until thicker panels could be used to new build stages.  Not sure how ULA will do things.  Manufacturing is different these days.

 - Ed Kyle

The explosion took place not inside Centaur V, but outside Centaur V, due to the stage springing a leak and rapidly filling up the enclosed space around the Centaur V test article with gaseous hydrogen, which then exploded.

So, it was not the stage itself that exploded, but part of the test stand. Unfortunately for Centaur V, it was sitting inside the igniting cloud of gaseous hydrogen, so you can imagine what happened when the shockwave hit the extremely thin walls of Centaur V: crushed like a beer can. This released the remaining hydrogen which fed a large hydrogen fire for a the next 30 seconds.

Offline Jim

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t several Centaur V stages are in production

That was a given.  Production is concurrent with development testing.
« Last Edit: 06/26/2023 02:31 pm by Jim »

Offline Jim

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i find it highly ironic that despite all the bashing of the BE-4 engine being late, turns out its the tried and proven centaur that ultimately delayed the launch of the vulcan lol ::)
It's a different beast, the 5m.

In its current form, as it will fly on the first several flights, it is in fact not much different from Centaur III DEC. Only major differences are the different diameter and the improved insulation. But for most other aspects, such as engine layout, RCS, tank pressurization, avionics, etc., it is highly similar to Centaur III DEC.

Not really, there are major differences like reversed common bulkhead, internal feed lines and all avionics mounted on the aft deck.

So testing of the upper stage was the critical path and not the BE-4 engines? Or did ULA stop all testing because they weren't sure the BE-4 engines could be made workable? Are there other explanations? Otherwise, I don't understand what happened.
Maybe we should call this thread the Padliner thread.

Offline Vettedrmr

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So testing of the upper stage was the critical path and not the BE-4 engines? Or did ULA stop all testing because they weren't sure the BE-4 engines could be made workable? Are there other explanations? Otherwise, I don't understand what happened.

Not involved, so don't have facts.  But I've been involved in this kind of development work in a prior career, and if you're not THE long pole then you don't get much outside publicity.  My guess is the Centaur development wasn't considered high risk, therefore didn't get much notice by us outsiders.
Aviation/space enthusiast, retired control system SW engineer, doesn't know anything!

Offline edkyle99

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So testing of the upper stage was the critical path and not the BE-4 engines? Or did ULA stop all testing because they weren't sure the BE-4 engines could be made workable? Are there other explanations? Otherwise, I don't understand what happened.
I noted it was the pacing item a year or two ago.  I based that observation on the fact that the test articles had not been built in time to support the originally-projected launch date.  Centaur 5 is, structurally, a brand new stage.  It was always going to be more complex, structurally, than the first stage.  But this is a new launch vehicle.  *Something* was going to pace the development, and who knows, there still may be *something else* before it is operational.

 - Ed Kyle 

Offline Purona

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So testing of the upper stage was the critical path and not the BE-4 engines? Or did ULA stop all testing because they weren't sure the BE-4 engines could be made workable? Are there other explanations? Otherwise, I don't understand what happened.

BE-4 was just the easy target to complain about for news articles and internet commentators.  Thats it really


So testing of the upper stage was the critical path and not the BE-4 engines? Or did ULA stop all testing because they weren't sure the BE-4 engines could be made workable? Are there other explanations? Otherwise, I don't understand what happened.

BE-4 was just the easy target to complain about for news articles and internet commentators.  Thats it really
I think you are right and that there is a lesson there.
Maybe we should call this thread the Padliner thread.

Online Robert_the_Doll

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So testing of the upper stage was the critical path and not the BE-4 engines? Or did ULA stop all testing because they weren't sure the BE-4 engines could be made workable? Are there other explanations? Otherwise, I don't understand what happened.

Neither.

All of it to some degree or the other was on the "critical path", but BE-4 was the most publicly prevalent on the radar given that it was one of the first major products from Blue Origin and a very complex as well as difficult one to bring to fruition, perhaps even than New Shepard in many ways. And because the other elements weren't given high profile scrutiny until only about early 2022, few were concerned, except a few of the more knowledgeable observers. And of those people, few wanted to because demonizing BE-4 and Blue Origin made for good clickbait on YouTube.

So, to the casual space observers, this completely blindsided them that something like this could even have happened.

Offline LouScheffer

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So testing of the upper stage was the critical path and not the BE-4 engines? Or did ULA stop all testing because they weren't sure the BE-4 engines could be made workable? Are there other explanations? Otherwise, I don't understand what happened.
This is a natural result of management trying to be as lean and efficient as possible during development.  Once one item (for example, the BE-4) is determined to be late, then all other components can assigned a lower effort level, until they are just ready (with some margin) before the new deadline.

In theory, this is the most efficient way to deploy people and other resources, and will not affect the delivery date.  But in practice, if one of the subtasks encounters an unanticipated delay, it risks becoming the new critical path.  This is exactly what happened here.

Management of expectations is tricky business. There is organizational pathology associated with managers taking risks when setting expectations. Managers are put up against artificial and real walls and feel like they can't say no. I've been there many times, so I don't blame Tony Bruno; to my mind, he's the hero in all of this.
Perhaps ULA calculated that the upper-stage testing was low risk, playing the odds, they set expectations based on the gamble that testing would go well. Now we will find out how real the pressure put on ULA's management is. We will see what it all means.
Maybe we should call this thread the Padliner thread.

Online FutureSpaceTourist

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https://twitter.com/sciguyspace/status/1674133237160091648

Quote
ULA confirms Vulcan debut will launch NET 4Q 2023. It seems almost certain now that some NSSL Phase 2 missions will move from Vulcan to Falcon.

https://arstechnica.com/space/2023/06/ula-shipping-vulcan-upper-stage-back-to-factory-for-more-work/

Offline Newton_V

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Quote
ULA confirms Vulcan debut will launch NET 4Q 2023. It seems almost certain now that some NSSL Phase 2 missions will move from Vulcan to Falcon.
How does he come to that conclusion?  I would say it's more like a <1% chance they would move anything.  It's takes longer to re-integrate than wait.  Even if Centaur didn't pop it's top, Astrobotic was the only primary ready to launch on it's planned ILC.
Edit:  Maybe SF-106 but I'm not sure about that.
« Last Edit: 06/29/2023 08:36 pm by Newton_V »

 

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