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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

#21
post #9
post #3

> "The most likely root cause for the booster RUD (rapid unscheduled disassembly) was determined to be filter blockage where liquid oxygen is supplied to the engines, leading to a loss of inlet pressure in engine oxidizer turbopumps that eventually resulted in one engine failing in a way that resulted in loss of the vehicle," the company stated. "SpaceX has since implemented hardware changes inside future booster oxi…

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.

Also meaningful to consider that as a vehicle meant to be reusable, it's going to be pretty much impossible to keep the tanks pristine over time unless they add a cleaning process that would be expensive and time consuming to every refurbishment (which runs counter to Starship's goal of rapid reusability). Relative to all other rockets, SpaceX's are refueled pretty often.

Better to just design with filters.

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

#22
post #3

> "The most likely root cause for the booster RUD (rapid unscheduled disassembly) was determined to be filter blockage where liquid oxygen is supplied to the engines, leading to a loss of inlet pressure in engine oxidizer turbopumps that eventually resulted in one engine failing in a way that resulted in loss of the vehicle," the company stated. "SpaceX has since implemented hardware changes inside future booster oxi…

Here is a theory https://youtu.be/ZIisBG3NV8Y?t=4445 that there was a methane leak which could have caused solid methane which could block filters.

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

#23

This is good. Flight 1 had 63 corrective actions and it took 5 months to complete the report. This one took 3 months and had 17 corrective actions. They'll get to orbit this year for sure

I suspect if test flight 3 makes orbit then flight 5 will be delivering starlink satellites and then testing on the way back down. If I remember correctly, a starship can deliver 440+ starlink satellites compared to around 60 for falcon 9.

Probably why they're hoping to get permission for 9 launches this year. Even if they throw away the entire stack, it probably costs less than the equivalent number of F9 launches.

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

#25
post #24
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" ?

Exploded is a loaded term that has been ruined by media to make it so that people interpret even development testing as a failure.

RUD conveys the same idea of the vehicle losing structural integrity, serves as a bit of tongue-in-cheek humor for those who understand it, and limits the number of idiots screaming "look this project is obviously a scam" slightly.

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

#28

This is good. Flight 1 had 63 corrective actions and it took 5 months to complete the report. This one took 3 months and had 17 corrective actions. They'll get to orbit this year for sure

I suspect if test flight 3 makes orbit then flight 5 will be delivering starlink satellites and then testing on the way back down. If I remember correctly, a starship can deliver 440+ starlink satellites compared to around 60 for falcon 9.

Current falcon 9 launches can lift 22-24 starlink v2 mini satellites

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

#29
post #24
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" ?

Explode actually has a definition.

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

#30
post #5

This is good. Flight 1 had 63 corrective actions and it took 5 months to complete the report. This one took 3 months and had 17 corrective actions. They'll get to orbit this year for sure

I love that Superheavy/Starship can be profitable even if they are expendable.

Expending the second stage would almost certainly be cheaper per kg than Falcon 9, but I doubt this is still true if you have to expend the booster.

Keep in mind we would have to compare it to the ~20M marginal cost of a F9 launch, not the $70M sticker price that a customer would pay.

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