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SpaceX discloses cause of Starship anomalies as it clears an FAA hurdle

arstechnica.com

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Re: SpaceX discloses cause of Starship anomalies as it clears an FAA hurdle

#121

Post by chasd00 »

RecycledEle wrote: post #82
Tuna-Fish wrote: post #11

Earlier quoted context omitted.

Most rockets don't have fuel filters, but this requires their tanks to be kept in a much more strict state of cleanliness, and any failure to do so would result in mission failures. SpaceX has long had a very different idea about FOD than most other rocket companies, famously Merlin engine qualification testing contains ingesting stainless steel nuts.

Those are big tanks.

yeah and even if starship tanks are perfectly clean you would also have to assume the tanks on the trucks delivering the fuel/oxi are also perfectly clean. As well as storage tanks, plumbing, and everything else.

Re: SpaceX discloses cause of Starship anomalies as it clears an FAA hurdle

#122

Post by JumpCrisscross »

wiz21c wrote: post #24
cubefox wrote: post #13

It's funny that SpaceX is using the term "rapid unscheduled disassembly" unironically, despite it originally being a humourous euphemism.

Why can't they just say "exploded" ?

> Why can't they just say "exploded" ?

The rocket exploded because it was instructed to explode. In fact, one of the problems was that it didn’t explode on time: the flight-termination system did not destroy the vehicle immediately.

Many rocket failures, especially those are high altitude, do not explode in a classical sense. The correct term would be that they failed; RUD seems more fun.

Re: SpaceX discloses cause of Starship anomalies as it clears an FAA hurdle

#123

Post by chasd00 »

foobarian wrote: post #35
Sebb767 wrote: post #9

Earlier quoted context omitted.

Why do those rockets have a fuel filter at all? I get why we have them in cars; we refuel quite often, in dirty environments and with possibly low quality fuel. For space rockets, it seems that it would be (comparatively) easy to ensure that the tanks are clean and the fuel is of high quality. On the other hand, if there wasn't any dirt, the filters would not have clogged, so I guess it does make sense after all.

In my mind a rocket engine would be much more tolerant of debris since you just pipe the fuel into a giant fireball (yes I can practically see the eyes rolling, sorry! :-). For ICEs I can understand clogging tiny injectors or carbs would be a problem, do rocket engines also have injectors or other narrow parts susceptible to clogs?

The thing is the energy density, flow rate/volume, and heat flux in a raptor is just so extreme. For example, there's two turbopumps operating at around 100k HP each in a volume not much bigger than the propane tank on your grill.. and those are basically just fuel pumps, not even where the real party is (pre-burners and combustion). Anything not going according to plan like a very small piece of debris in a filter causing turbulence or a change in flow rate is almost always catastrophic.

Re: SpaceX discloses cause of Starship anomalies as it clears an FAA hurdle

#124

Post by blendergeek »

akira2501 wrote: post #112
bradley13 wrote: post #66

I haven't watched launches since the space shuttle days. I have watched both of the Starship launches, and will watch all of them that I can. Excitement about space is back with a vengeance!

> Excitement about space Genuinely, or just because the marketing for it is that good?

Starship is the most powerful rocket in history and should be the first ever orbital launch system that is fully reusable. I don't know what you consider to be "genuinely" exciting, but I would consider entirely new generations of rocket launch tech to be genuinely exciting.

Re: SpaceX discloses cause of Starship anomalies as it clears an FAA hurdle

#125

Post by colechristensen »

Covzire wrote: post #113
somenameforme wrote: post #33

Earlier quoted context omitted.

Atlas 5 is already completely obsoleted by the Falcon Heavy which costs about half as much, for a reusable launch, and carries about 3x as much. But for Starship, most people don't seem to realize what a potential game changer this is. The goal for Starship is to get costs down to about 15x less than Falcon Heavy. When you can start sending stuff to space for a few dollars per pound, we're not talking about just prob…

Mini-factories in space could become a thing, supposedly a lot of industrial processes are only difficult because of friction and gravity.

Asteroid mining I think is one of the most interesting initial space industries. Something silly like a single asteroid having metals with current valuations of a million times the global GDP. Obviously you can't sell for that much but asteroid mining could make a lot of commodities become insanely cheap, and that would enable some pretty amazing things here at home, and in space.

Like what if steel were cheaper than plastic? If there was enough of it around to build a bridge between New York and London? If you could build a ship the size of Manhattan and then a city on top of it to roam the oceans? If you could build entire cities in orbit or city-ships that slowly wandered the solar system.

Re: SpaceX discloses cause of Starship anomalies as it clears an FAA hurdle

#126

Post by bryanlarsen »

looofooo0 wrote: post #117
bryanlarsen wrote: post #42

Earlier quoted context omitted.

It might actually be cheaper even if the booster is expended. Falcon9 is estimated to cost about $30M/launch. $20M to build the upper stage, and $10M to launch. Starship is estimated to cost about $100M to build both the booster and the second stage. Add $10M to launch. So 17t/$30M vs 150t/$110M.

110m crazy, a380 was 4x

$110M is insane. Anything under $1B seems unfathomable. $25M for a 2MN full flow staged combustion engine seems cheap. SpaceX plans on building them for $250K a piece. They're not there yet, but current estimates of $1M a piece are just as insane.

Re: SpaceX discloses cause of Starship anomalies as it clears an FAA hurdle

#128

Post by chasd00 »

inglor_cz wrote: post #110
pantalaimon wrote: post #69

Earlier quoted context omitted.

> if the fuel side clogs, the oxidizer might eat your chamber wall Ah, good old 'engine rich combustion'

I still remember the exhaust plume of one of the experimental Starships turning green. "Whoa, it is eating itself!" And verily it was.

yeah copper burns green and is commonly used in liners and other components. If it starts to burn, which it's not suppose to, you see green. You'll see a green flash when the merlin engines startup but that's because of the hypergolic fluids used to get the pumps running and ignition started, not copper burning. During Falcon night launches you can really see the green glow of the starter fluid on ignition.

Re: SpaceX discloses cause of Starship anomalies as it clears an FAA hurdle

#129

Post by gibolt »

foobarian wrote: post #104
TeMPOraL wrote: post #99

Earlier quoted context omitted.

I wouldn't notice. I stop watching them, because they got boring . Let me say that again: space launches got boring . I hoped, but never believed, I'll live long enough to see this happen.

Not only that, but freaking first stage landings got routine. Not quite boring yet - I still tear up any time I see one :-)

Watched up until #30, but it gets old watching the exact same thing that many times.

Exactly what you want for a reliable space vehicle.

Re: SpaceX discloses cause of Starship anomalies as it clears an FAA hurdle

#130

Post by ordu »

akira2501 wrote: post #112
bradley13 wrote: post #66

I haven't watched launches since the space shuttle days. I have watched both of the Starship launches, and will watch all of them that I can. Excitement about space is back with a vengeance!

> Excitement about space Genuinely, or just because the marketing for it is that good?

What the difference? Do you think people pretend to be interested in a product when marketing is good?

I think they become genuinely interested. People pretend when there are some benefits from pretending, social or monetary or whatever.

I can say for myself that my excitement about space is genuine, but I cannot say is it a result of the marketing. When two Falcon 9 boosters land side by side with a sub-second interval is it marketing or engineering excellence? I do not care, I like that moment, it seemed unreal at the time, it changed my perception of what is real and what is not. In other words it changed my perception of reality. It is a big deal, and I cannot care less if it is a marketing.

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