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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

#11

Post by Tuna-Fish »

Sebb767 wrote: post #9
tromp wrote: 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.

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.

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

#12

Post by teeray »

mrgaro wrote: post #8
rbanffy wrote: post #4

Earlier quoted context omitted.

I wonder the kind of sensor package they fly to be able to get to this conclusion. I have a real passion for monitoring things (for me, mostly web apps and data/message flows) and this is a really interesting case.

SpaceX is at least known to have some kind of high resolution/precision microphones around the structure recording constantly so that they are able to do 3D triangulation inside the vehicle.

Interesting, so they monitor the vehicle like it’s an earthquake

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

#14

Post by baq »

rbanffy wrote: post #5
martythemaniak wrote: post #2

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.

There are customers from three letter agencies who could find a use for this payload capacity, for sure.

OTOH imagine if a reusable launch of this costs approximately the same as an expendable Atlas 5 in it's most performant configuration and reliability is proven - NASA could launch a Pluto probe like New Horizons, except it'd be able actually make orbit over there.

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

#16

Post by cduzz »

Tuna-Fish wrote: post #11
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.

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...

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

#17

Post by Ajedi32 »

Sebb767 wrote: post #9
tromp wrote: 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.

I was wondering about this as well. Maybe the filter isn't for dirt, but ice? (Water or solidified methane.)

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

#18

Post by mezeek »

teeray wrote: post #12
mrgaro wrote: post #8

Earlier quoted context omitted.

SpaceX is at least known to have some kind of high resolution/precision microphones around the structure recording constantly so that they are able to do 3D triangulation inside the vehicle.

Interesting, so they monitor the vehicle like it’s an earthquake

yes, it's also what helped them solve CRS-7

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

#19

Post by stoneman24 »

martythemaniak wrote: post #2

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.

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

#20

Post by HPsquared »

cduzz wrote: post #16
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.

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...

Probably more "qualification of the design", like those bird ingestion tests they do on airliner engines. And the test probably doesn't look too interesting, the nut might not even come out the other end.
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