totm nov 2023 SpaceX Discussion Thread

[tater]

 

[tater]

 

[tater]

 

[tater]

 

[tater]

live

 

[Brotoro]

Liftoff.

8th time on those fairings. Getting good at reusing them.

[tater]

never gets old

[Brotoro]

And landed.

Interesting lingering shots of the booster on the drone ship at the end.

[tater]

2 minutes:

 

1 minute

abort

~24 hour reset

[AckSed]

7 hours ago, Brotoro said:

Liftoff.

8th time on those fairings. Getting good at reusing them.

I think I actually saw the tip of the fairings glowing dull red during F9's ascent.

[CatastrophicFailure]

 

[tater]

3 hours ago, AckSed said:

I think I actually saw the tip of the fairings glowing dull red during F9's ascent.

I did as well.

[JoeSchmuckatelli]

20 minutes ago, CatastrophicFailure said:

 

I'm guessing Raptor wins that argument.

[RCgothic]

First R3 sighting?

 

 

[Minmus Taster]

What's going on with F9's second stage? The second stage engine looks like a Terrier XD

[tater]

35 minutes ago, Minmus Taster said:

What's going on with F9's second stage? The second stage engine looks like a Terrier XD

They have started using a shorter nozzle on the Mvac when performance doesn't demand they use the real one.

[zolotiyeruki]

What's the benefit of using the smaller nozzle on the second stage? A tiny bit of cost savings?

[Jacke]

5 minutes ago, zolotiyeruki said:

What's the benefit of using the smaller nozzle on the second stage? A tiny bit of cost savings?

If the performance of the larger nozzle isn't needed, a 1-for-1 exchange with payload mass for the reduced engine mass, as it's on the final stage.

[tater]

53 minutes ago, Jacke said:

If the performance of the larger nozzle isn't needed, a 1-for-1 exchange with payload mass for the reduced engine mass, as it's on the final stage.

The nozzle is incredibly thin/fragile, so while 100% true, the mass savings is pretty small. My guess is the few kg and few $ they save on materials is probably nothing compared to the cost of manufacture for a smaller nozzle. heck, maybe it's thicker—eliminating some mass savings in a trade for ease of assembly (no worries about bumping into one on the factory floor and wrecking it). I seem to recall an old picture of Mvac with a piece of paper on it saying not to touch

Yep, one of the first images in an image search for mvac:

 

[CatastrophicFailure]

There’s a story from the very first Falcon 9 launch, where they noticed the edge of the Mvac nozzle was damaged once it was on the pad. Rather than roll it back, they ran the numbers and figured out they could just trim the damaged bit off on the pad… with ordinary tin snips. 
 

So yeah, I’m given to think there’s negligible mass savings there, especially vs the loss in performance. Gotta be the mfg cost saved. 

[mikegarrison]

6 hours ago, CatastrophicFailure said:

There’s a story from the very first Falcon 9 launch, where they noticed the edge of the Mvac nozzle was damaged once it was on the pad. Rather than roll it back, they ran the numbers and figured out they could just trim the damaged bit off on the pad… with ordinary tin snips. 

That was the second F9 launch.

https://en.wikipedia.org/wiki/SpaceX_COTS_Demo_Flight_1

Edited May 21, 2023 by mikegarrison

[GuessingEveryDay]

Going to watch tomorrow's launch from Playalinda Beach, hopefully, as it'll probably be the last launch I get to watch in person!

Saturday, I'll be moving with my family to Huntsville AL, so my siblings get better education along with better teacher pay.

[Nuke]

9 hours ago, CatastrophicFailure said:

There’s a story from the very first Falcon 9 launch, where they noticed the edge of the Mvac nozzle was damaged once it was on the pad. Rather than roll it back, they ran the numbers and figured out they could just trim the damaged bit off on the pad… with ordinary tin snips. 
 

So yeah, I’m given to think there’s negligible mass savings there, especially vs the loss in performance. Gotta be the mfg cost saved. 

i always love crude fixes to complex problems. i hope an engineer came by and marked it with a sharpie first.  "cut it off at the top of the line, we didnt factor in the weight of the ink."

Edited May 21, 2023 by Nuke

[tater]

Coverage starts in ~90 minutes, but the launch is not until 5:37 Eastern, so no need to tun in for about 7 hours, lol.

[Hannu2]

13 hours ago, Nuke said:

i always love crude fixes to complex problems.

I hate crude fixes to complex problems. One part of my job is to sort out researcher's crude fixes to complex problems and make real fixes. Usually every saved minute for them takes an hour of my work time. Sometimes it is unavoidable, if they fix something to continue measurement campaign in distant locations but they do it also in lab next to my office.