SpaceX F9 : Starlink 6 (v1.0 L5) : Mar. 18, 2020 - Discussion

[envy887]

And, apparently, a process failure, not a wear failure.

Which is not necessarily better, because the process needs to be as well established as the design. However, the process for used boosters is likely different than for new boosters, so it should be straightforward to show this isn't a potential issue on new builds.

And now we know they at least partially disassemble Merlin for cleaning between at least some flights.

[mn]

And, apparently, a process failure, not a wear failure.

Which is not necessarily better, because the process needs to be as well established as the design. However, the process for used boosters is likely different than for new boosters, so it should be straightforward to show this isn't a potential issue on new builds.

And now we know they at least partially disassemble Merlin for cleaning between at least some flights.

If it was supposed to be cleared of left over alcohol and wasn't then it's a process failure.

If nobody thought of it and now they learned something new it's a different kind of failure, not sure what that would be the right term for that.

[Vettedrmr]

And, apparently, a process failure, not a wear failure.

Which is not necessarily better, because the process needs to be as well established as the design. However, the process for used boosters is likely different than for new boosters, so it should be straightforward to show this isn't a potential issue on new builds.

And now we know they at least partially disassemble Merlin for cleaning between at least some flights.

Maybe "better" because that process checklist can be updated pretty easily.  As strange as it seems, I still consider F9 to still be in a flight test mode, because things are still changing (the number of flights / booster, in this case).  When we had a problem crop up in flight testing that step would be corrected before the next flight, and it usually only took a couple of days to modify the process, document it, peer review it, and get it approved.

[intelati]

And, apparently, a process failure, not a wear failure.

Which is not necessarily better, because the process needs to be as well established as the design. However, the process for used boosters is likely different than for new boosters, so it should be straightforward to show this isn't a potential issue on new builds.

And now we know they at least partially disassemble Merlin for cleaning between at least some flights.

Maybe "better" because that process checklist can be updated pretty easily.  As strange as it seems, I still consider F9 to still be in a flight test mode, because things are still changing (the number of flights / booster, in this case).  When we had a problem crop up in flight testing that step would be corrected before the next flight, and it usually only took a couple of days to modify the process, document it, peer review it, and get it approved.

For me, a recovered F9 still is in test mode. Better now on a Starlink than a Starship

[abaddon]

And, apparently, a process failure, not a wear failure.

Which is not necessarily better, because the process needs to be as well established as the design. However, the process for used boosters is likely different than for new boosters, so it should be straightforward to show this isn't a potential issue on new builds.

And now we know they at least partially disassemble Merlin for cleaning between at least some flights.

If by "better" we mean "a quicker return to flight", and we look at e.g. Soyuz failures, I would argue it is "better".  Recall how quickly Soyuz returned to human space flight after a process error caused loss of mission at booster separation.

[quagmire]

Not sure whether it is more relevant here or in today's launch thread, but noticed in the launch broadcast today that 1051.4 did not get the cleaning treatment. Wonder if they decided to stop using it in light of the failure or every post-flight refurb doesn't need a cleaning.

[AndrewRG10]

Not sure whether it is more relevant here or in today's launch thread, but noticed in the launch broadcast today that 1051.4 did not get the cleaning treatment. Wonder if they decided to stop using it in light of the failure or every post-flight refurb doesn't need a cleaning.

I think that might be what Lauren meant when she said they didn't do cleaning treatment. I thought it was referring to cleaning the engines but you may be right. Means these boosters are gonna start looking much more worn if they aren't cleaning the soot of anymore.

[matthewkantar]

Does this mean they recovered the stage? Could they make this determination with out it?

[whitelancer64]

Not sure whether it is more relevant here or in today's launch thread, but noticed in the launch broadcast today that 1051.4 did not get the cleaning treatment. Wonder if they decided to stop using it in light of the failure or every post-flight refurb doesn't need a cleaning.

I think that might be what Lauren meant when she said they didn't do cleaning treatment. I thought it was referring to cleaning the engines but you may be right. Means these boosters are gonna start looking much more worn if they aren't cleaning the soot of anymore.

It sounded to me that only the specific cleaning, that was using isopropyl alcohol, was not done. Since we don't know where exactly this sensor is, it could be that just that specific line was not cleaned.

I strongly suspect that was a temporary measure while a more permanent solution, perhaps just an improved cleaning process, is worked out.

[whitelancer64]

Does this mean they recovered the stage? Could they make this determination with out it?

Yes, the booster used on this Starlink launch, 1051, was recovered. It landed quite nicely on OCISLY.

If you mean the previous Starlink booster that had the engine out, 1048, then no, that's likely in pieces on the bottom of the Atlantic.

Yes, they can make very specific determinations from telemetry data. The data from the sensor where the isopropyl alcohol ignited would be of primary interest. If whatever data that sensor was broadcasting showed readings consistent with the ignition of isopropyl alcohol in the feed line, then QED.

[rsdavis9]

Not sure whether it is more relevant here or in today's launch thread, but noticed in the launch broadcast today that 1051.4 did not get the cleaning treatment. Wonder if they decided to stop using it in light of the failure or every post-flight refurb doesn't need a cleaning.

I think that might be what Lauren meant when she said they didn't do cleaning treatment. I thought it was referring to cleaning the engines but you may be right. Means these boosters are gonna start looking much more worn if they aren't cleaning the soot of anymore.

It sounded to me that only the specific cleaning, that was using alcohol, was not done. Since we don't know where exactly this sensor is, it could be that just that specific line was not cleaned.

I strongly suspect that was a temporary measure while a more permanent solution, perhaps just an improved cleaning process, is worked out.

I would suspect it is a sensor that is subjected to possible soot and doesn't need to be cleaned every launch.
The new process to clean would probably be to spray in isopropyl followed by air blast to dry.

[quagmire]

Not sure whether it is more relevant here or in today's launch thread, but noticed in the launch broadcast today that 1051.4 did not get the cleaning treatment. Wonder if they decided to stop using it in light of the failure or every post-flight refurb doesn't need a cleaning.

I think that might be what Lauren meant when she said they didn't do cleaning treatment. I thought it was referring to cleaning the engines but you may be right. Means these boosters are gonna start looking much more worn if they aren't cleaning the soot of anymore.

That is what I meant by 1051.4 not getting the cleaning process was the engine cleaning with the alcohol. The presenter stated that the booster on today's flight did not get that cleaning. So I was curious on if it didn't get that cleaning as a result of it causing the engine failure on this threads topic( the Starlink 6 launch back in March) or it isn't required for every post-flight.

[Barley]

And, apparently, a process failure, not a wear failure.

Which is not necessarily better, because the process needs to be as well established as the design. However, the process for used boosters is likely different than for new boosters, so it should be straightforward to show this isn't a potential issue on new builds.

And now we know they at least partially disassemble Merlin for cleaning between at least some flights.

The process for the flight leader might be different from the planned operational process.  This booster might get extra inspections, accompanied by extra cleaning (to get a better view or remove inspectors' finger prints).

That would be a failure of the development process rather than the operational process per se.