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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

#221

Earlier quoted context omitted.

Way to misquote GP to confirm your preexisting bias. I think the quote you're looking for is: "So as manufacturing pathfinder, this is what success often looks like. " If blowing up a prototype enables changes to the manufacturing process that prevent the same thing happening later with a live crew on board, then it's considered a success. It doesn't matter who the CEO of the company happens to be.

On the other hand, perfection looks like nothing ever blowing up while job always getting done.

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

#222
post #65

Earlier quoted context omitted.

Fuel is very cheap. SpaceX has built their whole business around the idea that it's worth trading payload for re-usability.

SpaceX has built part of their business around the idea that it's worth trading a moderate amount of payload for re-usability as long as they can still reach the orbit their customers care about and it was considered an extremely risky bet before they made it routine. It doesn't make fuel cheap, let alone very cheap. Actually another significant part of SpaceX business is modern engineering and modern mean of product…

Musk has said the cost of the methane for one Starship/Super Heavy launch will be about $1 million.

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

#223
post #112

Earlier quoted context omitted.

Yeah, and with much higher required dv and more required stages this would be a huge problem. But we only need two stages to orbit when launching from Earth, so it's really not that big of a deal, and it turns out that optimizing for reusability ends up being a lot cheaper than optimizing for minimum fuel use. For example, it only costs $200k for a fuel load of Falcon 9 fuel. If you got rid of reusability you'd need…

Fuel becomes more expensive on reusable spacecraft. Granted, the first pound of fuel is cheap, but the costs keep rising. With one and done you have a larger mass fraction to work with. Reusable spacecraft operate on much tighter constraints. Every single wasted pound in Space X’s design likely costs them 100’s of thousands of dollars in lost profit over time.

Not sure what’s to disagree with about that: “The reusable Falcon 9’s performance to GTO is listed at 5,500 kilograms. The same rocket in fully expendable version can lift 50 percent more payload — 8,300 kilograms. For the Falcon Heavy, the performance to GEO is about 2.8x that of the reusable version” https://spacenews.com/spacexs-new-price-chart-illustrates-pe...

Reusable means cost savings, but it has a dramatic reduction in cargo capacity. This means more trips to get the same mass into orbit, which means mire fuel directly used and every extra lb in the design is then carried up multiple times while further requiring more trips.

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

#224

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…

What does pathfinder mean in the context of manufacturing?

Tabu search thru a semi-dynamic design space.

https://en.wikipedia.org/wiki/Tabu_search

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

#225

Earlier quoted context omitted.

On the other hand, perfection looks like nothing ever blowing up while job always getting done.

You never get the job done without blowing things up, in any field where you’re treading untrodden ground. See also: Soyuz 1, Soyuz 11, Challenger, Columbia, Apollo 1 - and that’s purely spacecraft which have killed people, never mind the vast list of experimental aviation deaths. Much better to blow up some prototypes than some humans.

Apollo 1 was afaik an unexpected engineering lesson. Challenger, and to a lesser extent Columbia, were failures of management not listening to engineers raising the alarm

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

#226
post #184
post #172

Earlier quoted context omitted.

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.

You're saying this to a community with the mantra, "move fast and break things."

If that ever was a dominant mantra on HN, it's certainly not these days. For better or worse, this place is not dominated by "disruptive" startup founders anymore. Nor does the community skew supportive of Facebook/Zuckerberg or their ethos.

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

#227
post #189

Earlier quoted context omitted.

On the other hand, perfection looks like nothing ever blowing up while job always getting done.

Unfortunately, for NASA and most other space companies before SpaceX came along, perfection looks more like almost nothing ever blowing up while almost nothing getting done...

And later on still blowing up far to many things.

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

#228
post #202

Earlier quoted context omitted.

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…

This is getting into the "really absolutely certain of the input criteria" category your initial parent was talking about

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

#230

Earlier quoted context omitted.

This twitter reply sums it up well: “SUCCESS! We now now max pressure the tank can hold and the damage a rupture might do.”

Ah so this wasn't an accident? They needed to know the pressure limits so they purposely blew the bulkhead?

It clearly was an accident, why would they put 3 rocket engines in it if they were going to stress test the tank?
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