Author Topic: SpaceX McGregor Testing Updates and Discussion (Thread 4)  (Read 538101 times)

Offline Nevyn72

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Re: SpaceX McGregor Testing Updates and Discussion (Thread 4)
« Reply #880 on: 02/02/2024 08:09 pm »
Could it have been a test of one of the engines from 1058?

They did say there was going to be some 'end of life' testing done to some of the components to learn how high usage, older parts were holding up...

Offline catdlr

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Re: SpaceX McGregor Testing Updates and Discussion (Thread 4)
« Reply #881 on: 02/02/2024 08:48 pm »
https://twitter.com/AdamCuker/status/1753531050171548065

Quote
SpaceX is pushing the limits of Raptors, on a test stand that is often used for the development program of the engine. This test is a good example, ending with a shower of sparks, providing good data on limits to engineers.
« Last Edit: 02/02/2024 08:49 pm by catdlr »
It's Tony De La Rosa, ...I don't create this stuff, I just report it.

Offline InterestedEngineer

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Re: SpaceX McGregor Testing Updates and Discussion (Thread 4)
« Reply #882 on: 02/02/2024 11:44 pm »
Because, you know if this was a test-to-failure or not?  (Performance, environment or lifetime?)

And if it wasn't, then this was likely an acceptance test, designed to find manufacturing faults, which can be due to process, or materials issues - but are acknowledged to occur sometimes (or else you wouldn't need acceptance tests)

Boeing OTOH flew passengers on an airplane that passed acceptance tests, with missing and under-torqued bolts (separate issues!) and unreliable documentation.

How is that comparable?


If it's an F9 accelerated life testing, then it's perfectly normal.

Acceptance tests should never fail at this level of consequence.  You don't find errors in parts using acceptance testing, you find faults in processes.  Failure at acceptance testing almost guarantees you are leaking defects into end-user scenarios, because tests never find 100% of defects, they are a sampling plan  for your manufacturing process.

 I base this on 5 years of mfgr and 25 years of design in the electronics area.

That being said, the hypothesis that this is F9 accelerated life testing is probably the most likely scenario.

Offline meekGee

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Re: SpaceX McGregor Testing Updates and Discussion (Thread 4)
« Reply #883 on: 02/03/2024 02:04 am »
Because, you know if this was a test-to-failure or not?  (Performance, environment or lifetime?)

And if it wasn't, then this was likely an acceptance test, designed to find manufacturing faults, which can be due to process, or materials issues - but are acknowledged to occur sometimes (or else you wouldn't need acceptance tests)

Boeing OTOH flew passengers on an airplane that passed acceptance tests, with missing and under-torqued bolts (separate issues!) and unreliable documentation.

How is that comparable?


If it's an F9 accelerated life testing, then it's perfectly normal.

Acceptance tests should never fail at this level of consequence.  You don't find errors in parts using acceptance testing, you find faults in processes.  Failure at acceptance testing almost guarantees you are leaking defects into end-user scenarios, because tests never find 100% of defects, they are a sampling plan  for your manufacturing process.

 I base this on 5 years of mfgr and 25 years of design in the electronics area.

That being said, the hypothesis that this is F9 accelerated life testing is probably the most likely scenario.

Not true about rocket engines, because the margins are low and the chain of consequences is very fast acting.

There's a flaw in your logic.  If acceptance tests shouldn't find defects, then why have them?

The answer is that there's no such thing as zero defects.  There's only probabilities.  The parts arriving at acceptance testing should already at a certain high reliability level, but the acceptance test increases the reliability.

It's not like they're finding defective engines everywhere.  Their engines are running at thousands of starts per year and not failing.

There's no reason to start yelling "negligence" or "incompetence" or whatever Boeing adjective you had in mind. (well, nouns, actually.)
ABCD - Always Be Counting Down

Offline InterestedEngineer

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Re: SpaceX McGregor Testing Updates and Discussion (Thread 4)
« Reply #884 on: 02/03/2024 05:06 am »

Not true about rocket engines, because the margins are low and the chain of consequences is very fast acting.

There's a flaw in your logic.  If acceptance tests shouldn't find defects, then why have them?

The answer is that there's no such thing as zero defects.  There's only probabilities.  The parts arriving at acceptance testing should already at a certain high reliability level, but the acceptance test increases the reliability.

It's a common view, but utterly wrong.  Acceptance testing is a method of measurement of quality of a process, it doesn't by itself improve quality without feedback into that process (and it's the wrong place to have feedback, so what it really measured is some feedback process isn't working correctly)

Offline meekGee

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Re: SpaceX McGregor Testing Updates and Discussion (Thread 4)
« Reply #885 on: 02/03/2024 06:33 pm »

Not true about rocket engines, because the margins are low and the chain of consequences is very fast acting.

There's a flaw in your logic.  If acceptance tests shouldn't find defects, then why have them?

The answer is that there's no such thing as zero defects.  There's only probabilities.  The parts arriving at acceptance testing should already at a certain high reliability level, but the acceptance test increases the reliability.

It's a common view, but utterly wrong.  Acceptance testing is a method of measurement of quality of a process, it doesn't by itself improve quality without feedback into that process (and it's the wrong place to have feedback, so what it really measured is some feedback process isn't working correctly)
In practical terms, it's the same.

Every process in the world has rejects.  There's no perfect process, just an illusion of one.

Even if it's 0.01%.  Acceptance testing of courses helps you measure that reject rate, but it's also another bar that pushes the reliability up another couple of orders of magnitude, since the reliability numbers get multiplied.

If you're passing acceptance tests with zero failure (depending on how field operations are) it may be that your test is not really testing.

Now you can switch back to your Boeing analogy.  The plane went into commercial service with a door that's held on place by a prayer.  Yes the plane clearly got accepted.

So your jump from "defect exposed in acceptance testing" to "OMG that's Boeing level" is not credible.  If anything, this is the opposite of what happened with Boeing.

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Offline FutureSpaceTourist

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Re: SpaceX McGregor Testing Updates and Discussion (Thread 4)
« Reply #886 on: 02/04/2024 04:59 am »
https://twitter.com/adamcuker/status/1753998533554806926

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Booster 1087 still undergoing testing at SpaceX in McGregor tonight. This Falcon Heavy center core will support the launch of NASA's GOES-U satellite.
@NASASpaceflight

nsf.live/mcgregor

Offline cpushack

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Re: SpaceX McGregor Testing Updates and Discussion (Thread 4)
« Reply #887 on: 02/05/2024 06:23 pm »
A thought occurred to me, this may have not been an issue with the Merlin, but rather an issue with the stand.

Is it just me or does this test on the horizontal stand from earlier this evening look like the raptor is absolutely cooking something a little ways away from the test stand. Image + test clip below. 

Offline catdlr

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Re: SpaceX McGregor Testing Updates and Discussion (Thread 4)
« Reply #889 on: 02/06/2024 03:45 am »
Is it just me or does this test on the horizontal stand from earlier this evening look like the raptor is absolutely cooking something a little ways away from the test stand. Image + test clip below. 

Great catch, good eyes.  Probably not another water deluge test as you would have seen water coming out of it before the engine fired up and the test wouldn't last that long.  My only other theory is to test a slab of perhaps a new version of heat tiles to simulate reentry.
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Offline FutureSpaceTourist

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Re: SpaceX McGregor Testing Updates and Discussion (Thread 4)
« Reply #890 on: 02/10/2024 04:46 am »
https://twitter.com/nerdplysgames/status/1756160795195449617

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Pop goes the Raptor! A sea-level Raptor engine experienced an Rapid Unscheduled Disassembly (RUD) on the Raptor Vertical stand earlier today.

Will have some stats in the thread below.

Watch earlier testing @NASASpaceflight's McGregor Live nsf.live/mcgregor

(1/2🧵)

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This test marks the 12th RUD recorded since McGregor Live started with three RUDS being since the start of the month. With two being Raptors and one Merlin. Which is the only Merlin RUD we have seen on McGregor Live
(2/2🧵)


Quote
Booster 1087 still undergoing testing at SpaceX in McGregor tonight. This Falcon Heavy center core will support the launch of NASA's GOES-U satellite.
@NASASpaceflight

nsf.live/mcgregor

So I must have missed it but this core is now gone from the test stand, and didnt complete a static fire test, correct? Wonder if there was some issue that required it to be sent back to hawthorne?

Offline FutureSpaceTourist

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Re: SpaceX McGregor Testing Updates and Discussion (Thread 4)
« Reply #892 on: 03/04/2024 04:00 pm »
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Throttling Raptor on the Tripod stand at SpaceX McGregor bids you a good morning.
nsf.live/mcgregor

https://twitter.com/nasaspaceflight/status/1764691390217249103

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Interesting observation is a lot of tests timed at 40 seconds with Raptors. It's like they are specifically testing something related to that burn time?

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Landing burn would take about 40 seconds

https://twitter.com/nasaspaceflight/status/1764696202384228565

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Apparently 18 seconds for booster landing burn. Ship should be similar, but still interesting.

Offline Nevyn72

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Re: SpaceX McGregor Testing Updates and Discussion (Thread 4)
« Reply #893 on: 03/06/2024 07:49 pm »
Would 40 seconds be the ship on orbit re-entry burn?

Offline LouScheffer

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Re: SpaceX McGregor Testing Updates and Discussion (Thread 4)
« Reply #894 on: 03/07/2024 10:42 pm »
Maybe 40 seconds is the acceptance test for new engines?  Long enough to rule out manufacturing errors, and reach steady state, so a longer burn would not tell you much more.

That would explain why there are a lot of these tests - they must be acceptance testing many engines if they want to hit a 1 per month test flight, as they have indicated.

Offline FutureSpaceTourist

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Re: SpaceX McGregor Testing Updates and Discussion (Thread 4)
« Reply #895 on: 03/08/2024 02:14 pm »
https://twitter.com/adamcuker/status/1765947053169942992

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Video of B1087 performing a 79 second static fire. @NASASpaceflight

twitter.com/alexphysics13/status/1765932660252168620

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After having been reinstalled on the McGregor booster stand, B1087 has just performed its qualification static fire test ahead of its launch later this year.

nsf.live/mcgregor

Offline FutureSpaceTourist

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Re: SpaceX McGregor Testing Updates and Discussion (Thread 4)
« Reply #896 on: 03/22/2024 05:52 pm »
https://twitter.com/jswartzphoto/status/1771207345927754005

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We donít see a Raptor RUD very often but there was a good one just now on the Tripod stand at McGregor.  Head over and watch the full test replay at nsf.live/mcgregor

The cows werenít impressed though 😂

@NASASpaceflight

Offline lykos

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Re: SpaceX McGregor Testing Updates and Discussion (Thread 4)
« Reply #897 on: 03/31/2024 01:04 pm »
Quote
..The cows werenít impressed though 😂

Is there evidence that the hearing of this cows is still normal?

If there are "Space Cowboys" maybe there are "Space Cows" too, or cows V-3?

Offline darkenfast

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Re: SpaceX McGregor Testing Updates and Discussion (Thread 4)
« Reply #898 on: 03/31/2024 01:43 pm »
Quote
..The cows werenít impressed though 😂

Is there evidence that the hearing of this cows is still normal?

If there are "Space Cowboys" maybe there are "Space Cows" too, or cows V-3?

That's just bull...

I'll see myself out.
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