totm nov 2023 SpaceX Discussion Thread

[Treveli]

1 hour ago, Scotius said:

Where's the will, there's a way. Moon Cow Farm TM to the rescue! First build hydroponic fodder farms. Then bring calfs from Earth. Start filtering cow gaseous waste products from the air. Now you have plenty of methane AND Moon cheese to sell on Earth for a tidy profit.

 

You make a joke, but if Musk hears it, he'll probably put it down on his 'to do' list.

[kerbiloid]

26 minutes ago, MinimumSky5 said:

but the Moon is highly lacking in hydrogen and carbon. 

Nitrogen also suffers.
Almost nothing lightweight except oxygen, bound in tough compounds.

Edited June 24, 2019 by kerbiloid

[tater]

This is the one I expected a reaction to:

 

$200,000 per engine.

 

Also a new tweet:

 

[tater]

 

[tater]

 

[StrandedonEarth]

Hey, I like that timing, right when I’m usually getting ready for bed. I’ll be dreaming of Merlins firing all over the place. 

[Geonovast]

4 minutes ago, StrandedonEarth said:

Hey, I like that timing, right when I’m usually getting ready for bed. I’ll be dreaming of Merlins firing all over the place. 

Hopefully they'll hit the beginning of the window.  I'd like to see it live, and 10:30-11:00 Central Time is right when I'm getting to bed.

[Terwin]

9 hours ago, CatastrophicFailure said:

And then...

 

?!? Wait, what?

Would this mean SS/SH needs 'landing' engines with deep throttling, and the rest would be 'take-off' engines with higher max-thrust?

Perhaps Both atmospheric would be the landing variant for SS with the 4 vacuum engines having the max-thrust variant? 

SH would probably have 2-4 'landing' with the rest 'liftoff', giving the 31 engines ~37 engines worth of thrust(unless they decide to just reduce it to 26-27 engines total) 

 

1000 uses does not sound terribly unreasonable.

Even high-performance jet engines are slated to last 3000+ hours of operation, and total burn time for a F9 looks to be in the neighborhood of ~10 minutes(across both stages: 3 min then 6.5 min). (long-life jet engines are more like 30K hours of operation)

Double that for landing as well(which actually has much shorter burns using fewer engines), and you have about 333 hours of operation which is about an order of magnitude lower than even a high-performance jet engine.

Just the first order approximation of 'less than 1/10 of the operating life of a high-end jet engine, or less than 1% of the operating life of a long-lasting jet engine' makes 1000 flights seem very doable for a long-life rocket engine.

 

[tater]

 

[CatastrophicFailure]

 

[CatastrophicFailure]

3 hours ago, StrandedonEarth said:

Hey, I like that timing, right when I’m usually getting ready for bed. I’ll be dreaming of Merlins firing all over the place. 

Let’s all hope they’re all firing in the same place, in a very orderly fashion... 

2 hours ago, Geonovast said:

Hopefully they'll hit the beginning of the window.  I'd like to see it live, and 10:30-11:00 Central Time is right when I'm getting to bed.

I’m hoping for an hour’s delay myself,  that’s right when I’m heading home.

8 hours ago, Scotius said:

Where's the will, there's a way. Moon Cow Farm TM to the rescue! First build hydroponic fodder farms. Then bring calfs from Earth. Start filtering cow gaseous waste products from the air. Now you have plenty of methane AND Moon cheese to sell on Earth for a tidy profit.

 

Can you imagine it, tho? Happy cows bounding around as light as deer in a great domed pasture! Ooh! Ooh! The cows could literally jump over the moon! 

And all that moon-cow poop to fertilize the grass or ferment into more methane. 

Edited June 24, 2019 by CatastrophicFailure

[RealKerbal3x]

STP-2 hype! I have a feeling they’re kind of pushing it with the centre core downrange landing though...

Looking forward to...watching the replay in the morning 

[tater]

 

[Racescort666]

Do you think that Elon holds a design review before these tweet storms “ok guys, what’s the status of raptor? I feel like logging back into twitter today.”

[tater]

 

[mikegarrison]

1 hour ago, Racescort666 said:

Do you think that Elon holds a design review before these tweet storms “ok guys, what’s the status of raptor? I feel like logging back into twitter today.”

Are you kidding? He literally almost sent himself to prison with ill-advised tweets about Tesla. He's obviously a loose cannon when it comes to Twitter.

[Guest]

3 hours ago, CatastrophicFailure said:

 

This is why you don’t compose twitter posts after a couple of glasses of wine XD

26 minutes ago, mikegarrison said:

Are you kidding? He literally almost sent himself to prison with ill-advised tweets about Tesla. He's obviously a loose cannon when it comes to Twitter.

I like it! Though some of his posts about being Elon Chan or whatever were a tad embarrassing >_<

 

[Shpaget]

Those tweets are insane. 500 engines per year and 1000 flights out of an engine sounds insane.

500 engines per year, 1000 flights per engine, 34 engines per flight = 40 flights per day.

He is serious about rocketliners (point to point Earth passenger service)?

[mikegarrison]

6 hours ago, Terwin said:

1000 uses does not sound terribly unreasonable.

Even high-performance jet engines are slated to last 3000+ hours of operation, and total burn time for a F9 looks to be in the neighborhood of ~10 minutes(across both stages: 3 min then 6.5 min). (long-life jet engines are more like 30K hours of operation)

Double that for landing as well(which actually has much shorter burns using fewer engines), and you have about 333 hours of operation which is about an order of magnitude lower than even a high-performance jet engine.

Just the first order approximation of 'less than 1/10 of the operating life of a high-end jet engine, or less than 1% of the operating life of a long-lasting jet engine' makes 1000 flights seem very doable for a long-life rocket engine.

First, you have to understand where the wear and tear comes from. Engines (and airplanes) count both hours of operation AND "cycles". Some wear is simply cumulative from operational hours, but much of the most severe wear is from cycles. Heating things up and then cooling them down is a source of stress. Startup has different loads than steady-state operation. Cold oil does not lubricate the same as warm oil. Etc.

Also, airplane engines are sized for max takeoff thrust, but they spend very little time actually at that condition. They would wear out much faster than they do now if they were at max thrust all the time.

Furthermore, engines last for thousands of hours between refits because it is worth it to the customers to pay for that ability. Turbojets installed in cruise missiles can only run for a 100 hours or so before failure, but since their entire operational life is one cycle and a few hours of flight, nobody bothers to make them last more than that.

[tater]

 

[Brotoro]

Those are the droids I was looking for.

[cubinator]

17 minutes ago, tater said:

 

Spoiler

 

[tater]

 

[CatastrophicFailure]

 

38 minutes ago, tater said:

 

@tater‘s tweet... that’s SN4, I’m guessing, there for fit checks. No idea where they’d fly from nearby. 

[StrandedonEarth]

9 hours ago, tater said:

 

As I was going through and saving some more desktop backgrounds, I noticed they've done quite a bit with the cladding on the tower at 39A. Didn't notice that before. *looks closer* Or is it just wrapped in some sort of space-tarp?