totm nov 2023 SpaceX Discussion Thread

[cubinator]

Water is a rather finite resource on the Moon...mining it for rocket fuel might be unsustainable in the long run.

[kerbiloid]

1 hour ago, cubinator said:

Water is a rather finite resource on the Moon...mining it for rocket fuel might be unsustainable in the long run.

It makes great sense: to explore the Moon to mine the ice to fuel the rocket, to explore the Moon to mine the ice to fuel the rocket, to explore the Moon to mine the ice to fuel the rocket, to explore the Moon to mine the ice to fuel the rocket, to explore the Moon to mine the ice to fuel the rocket..

 

Edited August 26, 2020 by kerbiloid

[CatastrophicFailure]

1 hour ago, cubinator said:

Water is a rather finite resource on the Moon...mining it for rocket fuel might be unsustainable in the long run.

It just needs to hold out long enuf that we’re mining asteroids and/or Titan. 

[kerbiloid]

The humanity mission is to turn the lunar cryosphere into the lunar atmosphere.

[DDE]

4 hours ago, tater said:

WTH does that burn, coal?

 

4 hours ago, mikegarrison said:

Probably burns what most ships burn -- any old tarry junk left over after the refinery has cooked off the good stuff.

Of the worst variety. The Soviet Navy deliberately built the Kuznetsovs, the Sovremennyis

Spoiler

and even the secondary powerplant on the nuclear Kirovs

Spoiler

to run on "mazut", effectively WWII-vintage heavy bunker oil, to conserve diesel (roughly twice as expensive) for the turbine-powered ships. Combine that with poorly-maintained boiler automation, and you get... memes.

[CatastrophicFailure]

22 minutes ago, DDE said:

Of the worst variety

And I thought the coal-rollers were bad over here. 

Interesting gleanings from the NSF forum: there’s now a second, rather rusty, test stand that they’ve installed the thrust simulator on. This is probably where SN7.1 will end up for cryo testing, maybe future SNs, too. And speaking of future SNs, a segment of the nascent SN9 has a wide section of welded-on ponies for heat shield tiles.  Seems unlikely the whole thing will be shielded but it’s a positive next step after 8. 

[RealKerbal3x]

Seems like they may have repaired (at least some of) SN5's damage for its next hop! The shot at 3:09 is from a distance but it looks to me like the heatshield tiles have been repaired or replaced.

 

[zolotiyeruki]

15 hours ago, derega16 said:

Why not make mega catamaran out of tankers? Gap between two hull is a flame trench on its own with landing pads on both end and launch pad in the middle and such size can accommodate giant methane plant, inspection and refurbishment facility easily.

They'd never put the methane plant, let alone storage, that close to the launch pad, for the same reason that the fuel tanks at LC-39a are 1,000ft away from the launch pad.

[Flying dutchman]

I want to see sn5 and sn6 launch simultaniously, cross each other in flight and both land.

[CatastrophicFailure]

Looks like we’ll be waiting another day for that hippity-hop:

But, might get to actually watch on a weekend. 

[tater]

12 minutes ago, CatastrophicFailure said:

But, might get to actually watch on a weekend. 

 

[zolotiyeruki]

On 8/25/2020 at 4:42 PM, derega16 said:

Why not make mega catamaran out of tankers? Gap between two hull is a flame trench on its own with landing pads on both end and launch pad in the middle and such size can accommodate giant methane plant, inspection and refurbishment facility easily.

For the same reason the fuel tanks at LC-39a are 1000 feet away from the pad.

[CatastrophicFailure]

[Nefrums]

On 8/26/2020 at 5:08 AM, cubinator said:

Water is a rather finite resource on the Moon...mining it for rocket fuel might be unsustainable in the long run.

Well according to wikipedia:

moon is 0.1% water.  moon mass is in the order of 10^22 kg,   starship has in the order of 10^6 kg fuel.

so we can only fuel it 10^12 times with water from the moon. 

[mikegarrison]

9 minutes ago, Nefrums said:

Well according to wikipedia:

moon is 0.1% water.  moon mass is in the order of 10^22 kg,   starship has in the order of 10^6 kg fuel.

so we can only fuel it 10^12 times with water from the moon. 

That would work great! (Assuming all the water is in one place.)

[magnemoe]

10 hours ago, zolotiyeruki said:

For the same reason the fuel tanks at LC-39a are 1000 feet away from the pad.

Think 1000 feet will be inside the fireball with an catastrophic SH+SS fail, its around 5000 ton, who is almost double as much as the Soviet N1. 

[zolotiyeruki]

10 hours ago, magnemoe said:

Think 1000 feet will be inside the fireball with an catastrophic SH+SS fail, its around 5000 ton, who is almost double as much as the Soviet N1. 

Nah, I was just pointing out why you wouldn't want to put your LNG plant in the same hull as your launch pad.  The size of SH+SS only reinforces that reasoning.  1000' would definitely not be a safe perimeter.  A half dozen km *might* be.

[tater]

 

[magnemoe]

39 minutes ago, zolotiyeruki said:

Nah, I was just pointing out why you wouldn't want to put your LNG plant in the same hull as your launch pad.  The size of SH+SS only reinforces that reasoning.  1000' would definitely not be a safe perimeter.  A half dozen km *might* be.

Yes and even 300 meter makes ships off limit, pretty much the same with using oil rigs unless you want to run an underwater lox and liquid methane pipe. 
You can just accept you will loose the tank farm and plant together with rest of the structure at an pad explosion. 

Crew safety is more of an issue, now recovery crew is kilometres away even then landing and its something you can armor against, not an worst case pad explosion. 

[CatastrophicFailure]

So, this happened:

And then...

Let me emphasize, “might have a prototype booster hop done by then.”

Now, I’ll be danged impressed if they even have a Superheavy built by then, but still... 

the place is starting to look like Jeb’s spaceship parts yard by now...

 

[DDE]

2 minutes ago, CatastrophicFailure said:

Now, I’ll be danged impressed if they even have a Superheavy built by then, but still... 

Let me get my Elon Time conversion table...

[CatastrophicFailure]

2 minutes ago, DDE said:

Let me get my Elon Time conversion table...

Remember to compensate for SN5 hooping early. 

[DDE]

Just now, CatastrophicFailure said:

Remember to compensate for SN5 hooping early. 

I stopped being a skeptic the day Elon started building rockets in a scrapyard. Clearly the man has no brakes.

[RealKerbal3x]

11 minutes ago, CatastrophicFailure said:

might have a prototype booster hop done by then.

I feel like if they could at least get Super Heavy SN1 built by then, it would go a long way to show NASA that they're serious about this thing. Other than the grid fins, giant legs and 31-engine thrust puck, Super Heavy is essentially a stretched Starship tank section. 

I doubt they'd want to risk 31 engines on a short hop though (at the moment they don't have anywhere near 31 flight-ready Raptors) so the first Super Heavy will probably hop with only a few engines.

[Spaceception]

3 hours ago, RealKerbal3x said:

I feel like if they could at least get Super Heavy SN1 built by then, it would go a long way to show NASA that they're serious about this thing. Other than the grid fins, giant legs and 31-engine thrust puck, Super Heavy is essentially a stretched Starship tank section. 

I doubt they'd want to risk 31 engines on a short hop though (at the moment they don't have anywhere near 31 flight-ready Raptors) so the first Super Heavy will probably hop with only a few engines.

Isn't the core engine section made up of 7 engines? They showed that at one point. That would be a good first test which uses more Raptors than Starship, but not risking too many.

If they want Superheavy to be ready by mid-late October (I don't think the presentation will be early October if they're aiming to have some milestones completed), we should see the first SN1 ring sections coming out within the next week or so, right? Even if they're unable to hop, if they could pull off a successful cryo test, mounted Raptors, and maybe a static fire, that would be pretty good, and show it's not just a prop to the general public.

Does anyone think they could have Starship stacked on Superheavy? That would be a sight to see. But they would need a new crane for it, right? I don't think the current ones can reach high enough.