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SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident

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Re: SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident

#211

Post by ehnto »

aedron wrote: post #206
ehnto wrote: post #200

Earlier quoted context omitted.

I guess the parent comment was pointing out that this actually wasn't unexpected, it was one of the expected failure modes for the test and it happened. I don't see any constructive reason to look at it negatively, failure is part of testing. We don't test to find success, we test to find failures so that we can get them out of our systems.

Fine, so don't call it "success!". It's a step on the way to (possible) success, but the hypersensitivity isn't helping anyone.

Negatively responding to failure during a test is like negatively responding to someone asking a question. I am sure the circlejerk gets annoying, but it's at least got a constructive outcome. It's obviously not going to affect professionals and companies, but if you apply your view to students or people trying to work out new problems you could dissuade them from being inquisitive.

Re: SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident

#212

Post by hyperpallium »

double0jimb0 wrote: post #127

I read this was a manufacturing pathfinder. Manufacturing and assembly of high strength hardened steel is near black art. Pathfinders do exactly what they say, they lead you through unknown territory to the outcome of the manufacturing journey you embarked on. Often things go boom, you find out why, add it to your corpus of black art knowledge, and keep pathfinding until you run out of budget / succeed / change missi…

Soumds similar to tracer bullet development.

Re: SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident

#213

Post by tinco »

Roark66 wrote: post #167
double0jimb0 wrote: post #127

I read this was a manufacturing pathfinder. Manufacturing and assembly of high strength hardened steel is near black art. Pathfinders do exactly what they say, they lead you through unknown territory to the outcome of the manufacturing journey you embarked on. Often things go boom, you find out why, add it to your corpus of black art knowledge, and keep pathfinding until you run out of budget / succeed / change missi…

Why would they be using hardened steel for a pressure vessel that has to deal with vibrations? Also, someone on twitter said a horizontal weld failed. If this is true I'm surprised they didn't do two things: - tune their welding procedure by destructive testing with the same type of steel - and X-ray (or use another non-destructive method) the welds after assembly. Welding (including more interesting metals) is my ho…

Maybe they did both things, and the weld still failed. The rocket's being engineered, which means they make it as weak as possible without it blowing up. Those welds might be perfect in the x-rays, they might've done all sorts of destructive analysis, and still the thing might fail in staging.

Of course, they might also be on a deadline, and just went ahead and built it to spec and test it. But I don't think you can just say there's routine testing procedures that ensure rockets never blow up. If that were the case we wouldn't have needed SpaceX to reinvigorate the space industry.

Re: SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident

#214

Post by ryanmercer »

CPLX wrote: post #172
double0jimb0 wrote: post #127

I read this was a manufacturing pathfinder. Manufacturing and assembly of high strength hardened steel is near black art. Pathfinders do exactly what they say, they lead you through unknown territory to the outcome of the manufacturing journey you embarked on. Often things go boom, you find out why, add it to your corpus of black art knowledge, and keep pathfinding until you run out of budget / succeed / change missi…

I must admit that Elon has done some fairly impressive things, and I respect his hustle and innovation. With that said, the cult that surrounds his projects where people say things like "this is what success looks like" when a big metal thing blows up unexpectedly or robot car goes flying off an exit ramp is a never ending source of amusement.

>With that said, the cult that surrounds his projects where people say things like "this is what success looks like"

Experimental rocket/spacecraft (that's a fairly rapid prototype as far as rockets are concerned), made out of non-traditional material for rockets, fails one way yielding tons of data to do it better on the next version.

That's some modicum of success no matter how you slice it. Go plug 'rocket launch fail' or 'rocket explosion' or some such into YouTube and watch various rockets failing spectacularly on the launchpad both during development and carrying actual payloads and compare it to this failure at this stage of development.

I mean, look at stuff like Apollo 1. An electrical fire killed all of the crew during a test less roughly a month before launch. Starship is a very early prototype that probably yielded more actionable data than the Apollo 1 accident did.

Re: SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident

#215

Post by tomatotomato37 »

jacquesm wrote: post #210
cbhl wrote: post #169

Earlier quoted context omitted.

"SpaceX chose to use an industrial grade (as opposed to aerospace grade) ... cast part" Hmm.. Isn't this a common cost-cutting strategy for Musk's companies? The touchscreen in the Model 3s was (is?) also industrial grade, if I recall correctly.

> The touchscreen in the Model 3s was (is?) also industrial grade, if I recall correctly. Isn't that exactly what it should be? Or would you expect aerospace grade material there? Or is there yet another grade in between called 'automotive'?

Yup! I think the common electronic tolerances go: commerical, industrial, automative, military, aerospace, and then space, though I may be missing one or two.

Re: SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident

#216

Post by marktangotango »

CPLX wrote: post #172
double0jimb0 wrote: post #127

I read this was a manufacturing pathfinder. Manufacturing and assembly of high strength hardened steel is near black art. Pathfinders do exactly what they say, they lead you through unknown territory to the outcome of the manufacturing journey you embarked on. Often things go boom, you find out why, add it to your corpus of black art knowledge, and keep pathfinding until you run out of budget / succeed / change missi…

I must admit that Elon has done some fairly impressive things, and I respect his hustle and innovation. With that said, the cult that surrounds his projects where people say things like "this is what success looks like" when a big metal thing blows up unexpectedly or robot car goes flying off an exit ramp is a never ending source of amusement.

Cult not withstanding, Elon has expressed on a few occasions how he's expected some rockets to blow up, and a few have. I've had the idea the past few years that he's felt he hasn't been pushing the envelope hard enough. Progress on Starship has been at an astonishing rate by anyone's measure.

I find it fascinating that we get to observe this all playing out in real time. You might agree.

Re: SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident

#217

Post by missosoup »

contravariant wrote: post #31
roywiggins wrote: post #13

Earlier quoted context omitted.

Rockets are actually pretty easy to poke holes in. They're meant to keep stuff in, not out. A dropped torque wrench blew up a Titan. https://en.m.wikipedia.org/wiki/1980_Damascus_Titan_missile_...

It's somewhat impressive that the actual nuclear warhead didn't so much as leak. Which is what's supposed to happen but still you don't usually design something to withstand a botched missile launch capable of 'catapulting' a 740 ton door.

There wouldn't be much to 'leak'. The nuclear material in weapons is relatively safe to handle as long as you don't ingest it. It's the post-explosion fission products that are nasty.

Also with nuclear weapons, as much engineering has gone into safety as into weapon design itself. It's astronomically improbable for a modern nuclear weapon to detonate prior to arming even if the explosive lens is set off.

The reentry vehicle is designed to come down at circa mach 14 so a little bit of heat and jostling isn't going to bother it.

Cool video about some of the engineering involved: https://www.youtube.com/watch?v=97t7Xj_iBv0

Re: SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident

#218

Post by Ari_Ugwu »

aedron wrote: post #206
ehnto wrote: post #200

Earlier quoted context omitted.

I guess the parent comment was pointing out that this actually wasn't unexpected, it was one of the expected failure modes for the test and it happened. I don't see any constructive reason to look at it negatively, failure is part of testing. We don't test to find success, we test to find failures so that we can get them out of our systems.

Fine, so don't call it "success!". It's a step on the way to (possible) success, but the hypersensitivity isn't helping anyone.

The semantics these days. Trade "success" for "progress"....but then also replace "accident" with "test result". Works both ways, so does the hyper-sensitivity.

We are silly animals. Links I can't help but click on....comments I can't help to respond to. The algorithms are winning.

Re: SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident

#219

Post by TeMPOraL »

jefftk wrote: post #202
TeMPOraL wrote: post #179

Earlier quoted context omitted.

Safety factors also mitigate stupidity (your bridge is rated for load X, but someone drives 1.1 X through it because they're in a hurry) and cascade failures (a component upstream of yours fails and sends more load down your way).

Those both sound like kinds of ways the real maximum load could be higher than what you've called your maximum load

Only as long as your "real maximum load" != "announced maximum load". For the type of stupidity mitigation I mentioned, you want the real maximum load to be greater than the max load you announce to the customer/users. For mitigating cascade failures, you want the real maximum load to be greater than the maximum load value meant to be used internally by people designing other components in the system (though here, a smarter way would be to do a system-wide analysis of load flows to prevent cascade failures under user stupidity; however, here we're rapidly approaching the point at which I just talk out of my ass, having no real expertise on the topic).

Re: SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident

#220

Post by saalweachter »

dehrmann wrote: post #137
namirez wrote: post #85

Earlier quoted context omitted.

I don't know what happened here, but if I remember correctly, in rockets, safety factor is typically smaller than 2 or the design would be too heavy. But I guess the safety factor for pressure testing is 4. Source: article 6.8.2.2 of this document; https://www.faa.gov/about/office_org/headquarters_offices/as... Edit: I didn't see the "/s" before writing this comment.

> in rockets, safety factor is typically smaller than 2 or the design would be too heavy Safety factors feel like p-values. Why .05? Because. What if it's not good enough? We'll move the goal post.

Note that ptrue, it's the threshold for something to be interesting. If your p-values are greater than 0.05, you're wasting your peers' time trying to show off your work.
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