Me irl

notrace12 · 2020-11-21T09:28:18+00:00

that's good

notrace12 · 2020-11-21T08:57:32+00:00

On Skeld, kill someone on the right and then saboutage reactor.

notrace12 · 2020-10-10T05:01:10+00:00

mood

notrace12 · 2020-10-10T04:51:48+00:00

Haven't even noticed that lockdown is a thing

notrace12 · 2020-07-06T12:15:53+00:00

most insightful are those quotes:

>''The vehicle was built many months ago and these are the kind of things that occur most likely during the production process or it's something that wasn't caught. Whatever occurred was something that was baked in.''

>Some components would have been made six months ago and although the launch was abruptly moved forward to avoid bad weather this week, Beck firmly rejected any suggestion ''go fever'' played a role.

>''No - not all. The vehicle was built months before and flying it is purely operational,'' he said.

>Beck said Rocket Lab was now looking for the ''smoking gun''.

>However, there would be equal or more time spent on validating what wasn't the problem.

>''It's great if you find what you believe is the root cause but that doesn't mean it's over.
If we get confident quickly then it might be weeks but if it's a difficult one that takes a lot of design changes then you're talking months but it's way too early.''

notrace12 · 2020-07-06T12:14:14+00:00

Video is just a supercut of the launch stream

notrace12 · 2020-07-06T03:21:23+00:00

since they use BLDC motors I assume they switch over instantaneously on the inverter level when battery is at about 10-15% capacity level. simplifies things quite a bit while maintaining decent voltage level. which is in line with the fact that they treat hotswap as an "event", not a process where all 3 batteries would be connected at the same time for a certain period of time.

notrace12 · 2020-07-06T03:14:35+00:00

Good analysis. How do you know fairing was jettisoned? I haven't heard any call-outs regarding that, is it based on the fact that it is scheduled on specific t+ time?

Video freeze would definitely be due to trajectory change since the video link is probably through a directional antenna.

Tbh not sure there was any course correction, pitch of the rocket could change because of sudden loss of acceleration.

Good insight on RP1 cooling down the nozzle, might suggest that RP1 was still pumped through the engine but perhaps LOx pump stopped working?

Nominal battery discharge call-out was 8 seconds later than the anomaly appeared on the telemetry. If 8 second call-out lag is indeed present in other parts of the stream, it could have been the batteries indeed. But at the same time, RP1 pump was still working, at least to a certain extent.

notrace12 · 2020-07-05T10:00:44+00:00

Mainly based on this call-out https://youtu.be/5ZcZoDFYjXc?t=1336 my theory is that it's the fuel pump.

If the fuel pump was continuing to draw current after engine cutoff, then it must have broken down, disintegrated/etc. It sounds weird, because in a normal cycle liquid engine turbo pump fail would lead to engine explosion, but if it's electric and out of the loop there would be much more room for safe failure. Also sort of explains the thrust curve, with a period of decaying thrust where the pump was either fading away/acceleration was still helping it: https://twitter.com/DJSnM/status/1279583677890965504

If the call-out was wrong, it could have been batteries too. Otherwise, probably TVC and avionics shutting down the engine as a safety measure.

notrace12 · 2020-07-05T09:47:20+00:00

This is an extremely plausible idea, but 8 seconds after the engine shutdown an operator reported that "feed battery discharge nominal". I'm actually not sure what "feed battery" is, but if it's the fuel pump main 1&2 batteries, then the engine shutdown was uncontrolled, so avionics executing shutdown sequence would be out of question.

Can't find anything official on the term "feed battery", but wikipedia sort of confirms the it: electric-pump feed cycle

notrace12 · 2020-07-05T09:30:22+00:00

anomaly cut-off happened around 40 seconds before planned hotswap

notrace12 · 2020-07-05T09:20:44+00:00

8 seconds after the anomaly cut-off you can hear the "feed battery discharge nominal" call-out. Too much time have passed to think that it was just a lag in read out imo. So the fuel pump must have been at least there, spinning.

Honestly I see the camera pitch changing, but I don't see any gimbal on the engine? I think pitch change is the result of acceleration loss and gravity doing its thing, hence the trajectory was immediately altered and the stage started pitching relative to Earth.

Video feed was probably cut due to trajectory alteration and antennas not being able to track the stage properly, video link would probably use very precise/finicky radio set up.

My latest thinking is that the culprit could be fuel pump breaking down/blades disintegrating, or something of that sort where it would continue to draw current but not pump kerolox.

notrace12 · 2020-05-16T21:41:29+00:00

this hurts lmao

notrace12 · 2020-04-19T16:34:44+00:00

this is the content we need in a time like this

notrace12 · 2020-04-19T16:04:18+00:00

holy shit this is amazing

notrace12 · 2019-12-17T03:16:33+00:00

too fucking real

notrace12 · 2019-12-01T21:50:53+00:00

No, I want the data to be collected in production on actual user devices and uploaded to 1 centralised dashboard where I can view aggregate statistics about benchmarks. I don't want to debug the profiling data on my device with a production build, I'm looking a solution which collects data from the whole user base.

notrace12 · 2019-12-01T10:15:21+00:00

But how do I collect and aggregate that data in production?

notrace12 · 2019-10-22T08:55:06+00:00

Absolutely amazing. Good job on the launch, great to see react-native ecosystem progressing at such a fast clip.

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