totm nov 2023 SpaceX Discussion Thread

[sevenperforce]

3 hours ago, tater said:

That tiktok is flatly wrong. All medical tests have a false negative and false positive rate.

It was as much info as I could fit into the medium -- I didn't have time to go into the impact of Ct and doubling via amplification.

3 hours ago, tater said:

The true FP rate for PCR is very low, but not 0. A number I have seen is 0.4%. At low prevalence as a prior, a substantial % of tests become FPs.

True FP for COVID PCR is roughly 0.01% based on the Ontario guidelines.

3 hours ago, tater said:

Due to the exponential growth with each cycle, however, PCR detects virus LONG after people have recovered. At a cycle threshold of 40, out to ~12 weeks. People are not infectious after ~9 days (higher the sicker they are, with the longest times for ICU patients). They have been unable to culture live virus in anyone with a test that required 35+ cycles (most tests are 38-42 in the US), and from what I have read, no one is infectious if the CQ was over ~28-30. There was a talk at Santa Fe Institute I saw that suggested (months ago) that all the tests should be done at MUCH lower cycle thresholds, intentionally missing "cases" where people are already over it in favor of only detecting people actively infectious (very low CQ). So in an attempt to reduce FP rate by more cycles, they detect uninteresting "cases" of COVID-19.

Anything under Ct 25 means you're contagious. From 25-35 you're looking at a low risk of contagiousness; it's more probable that you've recovered. At 35-38 you're definitely not contagious but you still definitely had the virus recently. Above 38-40 cycles you get into the possibility of amplifying incomplete viral material.

They shouldn't stop cycling at 30; that's a bad idea. But they should report cycle threshold on positives so that physicians can make recommendations.

 

[Geonovast]

Let's keep it on topic, guys.  Please take the Covid discussion to the Covid thread.

[cubinator]

Well, better that they delay it now than tomorrow after I've told everyone at the planetarium about it. And I'll have more chance to watch the whole event.

Edited November 14, 2020 by cubinator

[RCgothic]

No fast rendezvous for Sunday's launch: 

 

 

[RealKerbal3x]

A Raptor was removed from SN8:

(scroll back to 4:25am on the LabPadre feed to watch it come out).

[tater]

My friend at MCC sent me a Crew-1 t-shirt I can wear tomorrow instead of my SpaceX F9 one (I have no sportsball team to root for ).

[RCgothic]

8 hours ago, RealKerbal3x said:

A Raptor was removed from SN8:

(scroll back to 4:25am on the LabPadre feed to watch it come out).

It was SN32

 

 

[RealKerbal3x]

5 minutes ago, RCgothic said:

It was SN32

I guess that liquid we saw dripped out through the nozzle, as I don't see any visible meltiness.

[RCgothic]

30 minutes ago, RealKerbal3x said:

I guess that liquid we saw dripped out through the nozzle, as I don't see any visible meltiness.

Are we certain it was molten metal and not just fluid on fire?

[RealKerbal3x]

1 hour ago, RCgothic said:

Are we certain it was molten metal and not just fluid on fire?

We don't know. It looked molten, though.

[Shpaget]

Didn't Elon say that hydraulics failed? Perhaps it was dripping burning hydraulic fluid?

[RCgothic]

 

Plumbing under the Methane turbopump has suffered critical existence failure.

 

Edited November 14, 2020 by RCgothic

[RealKerbal3x]

20 minutes ago, RCgothic said:

Plumbing under the Methane turbopump has suffered critical existence failure.

I guess that's what melted then.

[Geonovast]

59 minutes ago, Shpaget said:

Didn't Elon say that hydraulics failed? Perhaps it was dripping burning hydraulic fluid?

Pneumatics.

[CatastrophicFailure]

31 minutes ago, RCgothic said:

Plumbing under the Methane turbopump has suffered critical existence failure.

I hate it when that happens. 

9 minutes ago, Geonovast said:

Pneumatics

So... burning air, then?

In all seriousness, if the flarping fuel plumbing melted(!!!!!!), it’s really mind-boggling that the whole thing didn’t go all critical existence failure. 

[Elthy]

Maybe on shutdown a few valves of the preburner didnt close properly, leading to a more stochiometric=hotter flame which melted the housing like a bunsen burner. This could have been caused by failed pneumatics...

Edit: Elon Musk said that the engine failure caused the loss of pneumatics, not the other way around, so maybe something else kept the valves from closing.

Edited November 14, 2020 by Elthy

[tater]

 

[sir rocket]

5 hours ago, RCgothic said:

Plumbing under the Methane turbopump has suffered critical existence failure.

this should replace rapid unplanned disassembly.

[kerbiloid]

CREX-FEX

CRitical EXistence Failure EXhibition

[sir rocket]

[Flying dutchman]

9 hours ago, tater said:

 

Could someone perhaps draw a circle around where the molten pipes are? I have been looking at this image for 10 minutes now 

Edited November 15, 2020 by Flying dutchman

[sir rocket]

21 minutes ago, Flying dutchman said:

Could someone perhaps draw a circle around where the molten pipes are? I have been looking at this image for 10 minutes now :p

Me too

[RCgothic]

1 hour ago, Flying dutchman said:

Could someone perhaps draw a circle around where the molten pipes are? I have been looking at this image for 10 minutes now 

 

55 minutes ago, sir rocket said:

Me too

The turbopump is on the other side of the engine, it's not in that photo.

Edited November 15, 2020 by RCgothic

[Shpaget]

2 hours ago, Flying dutchman said:

Could someone perhaps draw a circle around where the molten pipes are? I have been looking at this image for 10 minutes now 

My friend also can't see anything wrong, apart from it it looking like a crumpled up loose ball of wire, or as if a spool of pipe fell of a cliff, then rolled down a hill and ended up as a winner of a crash derby.

That being said, I'm sure there is method to the madness. It works, right? Kind of, at least.

[tater]

Weather is 50% go for today, 80% on backup date Wednesday.