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

arstechnica.com

241–250 of 420 posts

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

#241
post #16

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.

That's bonkers. What size nuts do they pass through their engine? Every engine before it goes to space has to have a nut passed through the system? Like a 12mm "go into space" grade nut or a little itty bitty nut like I might find holding down a heat sink assembly in a 1998 vintage motherboard? I'm off to the googles to find videos...

The tradition of passing nuts comes at least from the history of developing engines for Soviet Moon launcher, N-1. The engines used on all four launches, NK-15, were notoriously unreliable, and the suspicion was that their turbopumps, having quite tight clearances, sometimes had rotors touching walls during work. In oxygen-rich environment that led to engine fire. The engine which fixed those problems, NK-33, was working much better, and to demonstrate that it's robust for the problems like turbine misalignment, some metal parts, like nuts, were intentionally dropped into the propellant flow.

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

#242
post #215

Earlier quoted context omitted.

The downside is that rapid iteration doesn't always give the same insight in terms of scientific understanding. E.g., Design_A fails. We quickly pivot to Design_B, which works. However, we don't spend the time ultimately understanding why Design_A failed. This can be operationally great, but it can also risk conflating being lucky with being good. If you don't fundamentally understand why the thing failed the first t…

You can understand why design A failed. Just don’t need design B to be blocked on that with agile because the last iteration was working.

Sure, you can if you dedicate the resources to understanding the failure. What I saw personally is that is not always the case with SpaceX. In my experience, they changed a design and seemingly used that as an excuse to not further investigate the original design. (This was related to COPV failures. The general consensus seemed to be “we don’t need to understand why it failed because we’ve moved on to a different design.”)

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

#243
post #215

Earlier quoted context omitted.

Even SpaceX's methods of fail fast (and often explosively) is relatively cheap. SLS is doing it the hard and expensive way.

The downside is that rapid iteration doesn't always give the same insight in terms of scientific understanding. E.g., Design_A fails. We quickly pivot to Design_B, which works. However, we don't spend the time ultimately understanding why Design_A failed. This can be operationally great, but it can also risk conflating being lucky with being good. If you don't fundamentally understand why the thing failed the first t…

What's stopping them from choosing to revise design A over chosing design B?

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

#244

Earlier quoted context omitted.

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…

>Asteroid mining I think is one of the most interesting initial space industries.

I hope to see in my lifetime a large asteroid brought to Earth orbit, for both mining and as a very large space station.

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

#245
post #49

Earlier quoted context omitted.

Oh I agree it's not bonkers from the perspective of "wait you want to put people on that bomb and then explode it?" You can make all sorts of rules about what's not allowed to happen, but often those things happen. I'm just ... astonished if they've got a little practice room somewhere in their factory where they give each of their new rockets a nut to process... "Okay kid here's your graduation test!". A "we need sc…

Rockets: "Hey what if we strap people to a giant bomb and explode it juuust slowly enough that they're launched into space alive?"

Steam engines: "No problems, we're doing that already for centuries, just with less speed and mostly horizontally."

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

#246
post #238
post #220

Earlier quoted context omitted.

How well does this work when there is fundamentally little information? It works in stock trading because so much information is standardized and regulated. I am skeptical of it being as useful here simply because the crowds don't have much relevant information, as far as I know. For example, do the crowds know about the design redundancy? What about the supplier quality control? Or the reliability data on the check…

Engineering, physical principles, I guess. Those who place bets or making predictions may know a thing or two on mechanics, rocket science and history of building launchers.

To put a finer point on it, those seem like rather blunt instruments for prediction compared to how risk is typically measured by aerospace reliability engineers.

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

#247
post #13

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

Because the lawyers are not yet involved. If SpaceX blows up over a major city, these terms will be banned.

Rockets don't pass over cities for that reason.

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

#248
post #243
post #215

Earlier quoted context omitted.

The downside is that rapid iteration doesn't always give the same insight in terms of scientific understanding. E.g., Design_A fails. We quickly pivot to Design_B, which works. However, we don't spend the time ultimately understanding why Design_A failed. This can be operationally great, but it can also risk conflating being lucky with being good. If you don't fundamentally understand why the thing failed the first t…

What's stopping them from choosing to revise design A over chosing design B?

Nothing, other than it may just be easier to change the design to avoid the effort of a deeper investigation.

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

#249

Earlier quoted context omitted.

It’s so exciting to keep track of. Feels like everything I hoped to see happening in spaceflight back in the 90s and 00s is finally (maybe) becoming reality and absolutely shattering the stagnancy that had overcome the field, hopefully this time for good. If this pace can continue unabated, maybe it’s not too unrealistic to hope that my grandkids’ generation in a few decades has astronaut as one of their most aspired…

I am not sure if there is enough profitable space industry. Last I checked asteroid mining was not super feasible, but maybe some like space based solar.

The asteroid Psyche is expected to have a lot of gold content. NASA sent a probe last year, but it's a long trip and will take until 2029 to get there. Even then it just orbits.

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

#250
post #163

Earlier quoted context omitted.

His “antics” is why SpaceX became possible in the first place. If he cared what others think he wouldn’t have started it, and wouldn’t be who he is.

Not sure we're referring to the same "antics". You cannot deny that Elon has changed as a person ever since he got hooked on Twitter. A lot of his personality and how he acts these days is very much focused on trying to get the most likes. Pre-Twitter "fame", it's true that he disregarded what others thought, but he also wasn't so focused on maximizing his likes either. Twitter was like heroine for him, and he now li…

Maybe he didn’t “change”. Maybe you just see more of him now, and see how he actually is, foot in mouth and all. People who got very rich very early often lack the “filter” - they don’t have to consider your opinion of them. In fact, considering it would probably be strongly counterproductive if they’re ambitious. Popular opinion is akin to a lawn mower - stick your head out too far above others and you’ll lose it. But that’s for you and I, that logic doesn’t really apply to centibillionaires.
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