totm nov 2023 SpaceX Discussion Thread

[tater]

LOL

 

[sevenperforce]

On 1/10/2020 at 11:52 PM, tater said:

Oh, yo mean Mk1? Not sure we ever heard officially.

We didn't hear officially but I believe Elon said it was well over.

[tater]

26 minutes ago, sevenperforce said:

We didn't hear officially but I believe Elon said it was well over.

Elon tweets are about as official as we're likely to see

 

For you FL peeps who might watch IFA:

 

[tater]

 

[tater]

 

[Geonovast]

Is that an old picture?  I see a white interstage.

[sevenperforce]

8 minutes ago, Geonovast said:

Is that an old picture?  I see a white interstage.

Yes, it is B1045 from the TESS launch on April 18, 2018. You can just make out the edge of the TESS logo below the NASA logo on top.

Another view:

 

[ThatGuyWithALongUsername]

 

[ThatGuyWithALongUsername]

 

Wait, I thought the header tanks were suppose to use the nosecone as a bulkhead? Did the design change again?

[Rakaydos]

20 minutes ago, ThatGuyWithALongUsername said:

 

Wait, I thought the header tanks were suppose to use the nosecone as a bulkhead? Did the design change again?

Room for further optimization.

[sevenperforce]

1 hour ago, ThatGuyWithALongUsername said:

 

Wait, I thought the header tanks were suppose to use the nosecone as a bulkhead? Did the design change again?

So....beautiful.

I'm not sure on this point. Back when they were talking about Mk1, he either said "we'll eventually make the nosecone the tank" or "the orbital versions will make the nosecone the tank." I don't know which. It's certainly possible that the LOX header tank could be suspended inside the nosecone-turned-methane tank.

[magnemoe]

2 hours ago, sevenperforce said:

So....beautiful.

I'm not sure on this point. Back when they were talking about Mk1, he either said "we'll eventually make the nosecone the tank" or "the orbital versions will make the nosecone the tank." I don't know which. It's certainly possible that the LOX header tank could be suspended inside the nosecone-turned-methane tank.

You need to insulate them because reentry heat or longer stay in space. Also the tip is not very good for holding over-pressure. If anything they put the methane tank below the oxygen tank as an kind of cone. so you get an cone with an rounded top. 

One weird thing to me is that the Oxygen tank is on top in all the blueprints, yes probably reasons but looking at the engines I assumed the oxygen tank would be lowest so you could just pipe oxygen directly from the tank to the engine with an short pipe while the methane with it side intake would be feed from an manifold. 
Yes the 3 core engine also need to be feed from the header tanks but that is just 3 engines. On the superheavy that would be lots of weight saving espesialy as the outer rings does not gimbal.  
 

[sevenperforce]

1 hour ago, magnemoe said:

You need to insulate them because reentry heat or longer stay in space. Also the tip is not very good for holding over-pressure.

Next to a hemispherical section, an ogive cone is surprisingly good at holding pressure. And the whole thing is going to be insulated against re-entry heat anyway. Honestly having propellant right up against the metal is going to provide a heat sink which will be a little better than having nothing behind it.

1 hour ago, magnemoe said:

One weird thing to me is that the Oxygen tank is on top in all the blueprints, yes probably reasons but looking at the engines I assumed the oxygen tank would be lowest so you could just pipe oxygen directly from the tank to the engine with an short pipe while the methane with it side intake would be feed from an manifold.

The oxygen tank runs a central column pipe through the methane tank. Oxygen is more dense so this is a good idea; plus having heavy oxygen farther forward helps with aerodynamic stability on ascent.

[Wjolcz]

I don't think methane is that tricky to store in the nosecone. After all, people keep bottles of it in their homes where I live (well, actually in rural areas where I don't live but my grandparents do and they have just that). Having it as a heat sink makes sense too, I guess. Not sure if my logic is correct but here's an analogy: if you fly really fast (several Mach) in a conventional-ish plane the tip of the wings will heat up and most likely melt before the thicker part of the wing does. So, maybe they are trying to do just that with the nose cone by putting fuel in there?

[Xd the great]

1 hour ago, Wjolcz said:

if you fly really fast (several Mach) in a conventional-ish plane the tip of the wings will heat up and most likely melt before the thicker part of the wing does. So, maybe they are trying to do just that with the nose cone by putting fuel in there?

Not sure, but I thought Raptors run on liquid propellants, not gas...

[sh1pman]

BTW, I’d absolutely, 100% go. 
Maybe not in the first group, though. 

[Raven Industries]

I wonder, what sort of jobs will be available on Mars that allows one to pay back those loans?

[tater]

14 minutes ago, Raven Industries said:

I wonder, what sort of jobs will be available on Mars that allows one to pay back those loans?

This, until they find sandworms, and the Spice.

The first city will be called (a friend uses this, I can't claim credit), "New Donner."

 

[mikegarrison]

8 minutes ago, Raven Industries said:

I wonder, what sort of jobs will be available on Mars that allows one to pay back those loans?

What are they going to do if you don't pay them back? Send you back to Earth?

This was an incredibly silly thing for Elon to post, actually. Going to Mars isn't like buying a house. It's more like packing your family into a covered wagon and heading out on the Oregon Trail. I imagine that for a lot of people it will be a one-way trip.

I think this reveals that Elon is very focused on building the capacity to get people to Mars but has no clue what is going to happen after that.

[tater]

1 minute ago, mikegarrison said:

What are they going to do if you don't pay them back? Send you back to Earth?

This was an incredibly silly thing for Elon to post, actually. Going to Mars isn't like buying a house. It's more like packing your family into a covered wagon and heading out on the Oregon Trail. I imagine that for a lot of people it will be a one-way trip.

Except that you can stop the wagon, and literally breath the air, find food everywhere, and stop someplace instantly habitable maybe every few days if you want.

It's like going in a covered wagon with zero ability to forage for anything, and once you get to the destination, you have to build a modern city before you can attempt farming, lol. The whole Mars thing is flatly nuts. I'm glad someone wants to do it, because transformational space travel comes along for the ride (ie: cheap), but Mars is bizarre to me as a place to move.

Just googled around and found 640 acres (1 square mile) in Ontario for $97,000. Why anyone would move to Mars when they could buy enough land to far more easily live off of---even if you had to WALK for weeks to get supplies, lol. (except it's a few hundred yards off a large road, and maybe 5 miles from a town). Where are all the people moving to arctic wastelands?

 

1 minute ago, mikegarrison said:

I think this reveals that Elon is very focused on building the capacity to get people to Mars but has no clue what is going to happen after that.

Yeah, the Mars thing... I get it on one level, but it's kooky.

[cubinator]

15 minutes ago, mikegarrison said:

I think this reveals that Elon is very focused on building the capacity to get people to Mars but has no clue what is going to happen after that.

No one person really knows or can decide what we do with Mars. Especially since the implications of it can change the next billions of years of the galaxy. 
It's pretty much impossible for just anyone to go on the early ships, unless they fully expect to live a short life and meet its end on Mars. It won't get to the point of 'just buy a ticket and go' for a long time, but I do think the mentality of building ships that can support that will get us there, even if it takes a couple hundred years (gotta remember that Elon Time is a thing).

[mikegarrison]

Didn't you ever play the Oregon Trail game? If you stop and just breathe the air you will end up dead trying to get across the mountains in the snow.

Anyway, OK, maybe it's too early for the Oregon Trail. Maybe it's more like Lewis and Clark. The people that went with Lewis and Clark didn't take out loans to buy their way onto the expedition; they were paid to go! And while they were out there they didn't expect to buy supplies and pay rent on their tents -- this was all communal. It wasn't a capitalist economic paradigm at all.

[tater]

9 minutes ago, mikegarrison said:

Didn't you ever play the Oregon Trail game? If you stop and just breathe the air you will end up dead trying to get across the mountains in the snow.

Anyway, OK, maybe it's too early for the Oregon Trail. Maybe it's more like Lewis and Clark. The people that went with Lewis and Clark didn't take out loans to buy their way onto the expedition; they were paid to go! And while they were out there they didn't expect to buy supplies and pay rent on their tents -- this was all communal. It wasn't a capitalist economic paradigm at all.

But again, it was also---compared to Mars---a trivial expedition.

The only places that compare (and even then, orders of magnitude easier) would be parts of Earth where no humans have ever lived before modern times (Antarctica springs to mind). Sail a boat (or canoe) across an ocean, land in the middle of nowhere---hard to survive for US, but that random spot? Already inhabited by effectively naked stone age tech people in much of the world, or people wearing furs (with little other tech, and maybe no metallurgy at all) if the spot is in the arctic.

I just don't think other human migrations are even analogous. Maybe the huge cities we have now at the bottom of the oceans are a better examp... oh, wait, we haven't done that yet, either .

 

[magnemoe]

4 hours ago, Wjolcz said:

I don't think methane is that tricky to store in the nosecone. After all, people keep bottles of it in their homes where I live (well, actually in rural areas where I don't live but my grandparents do and they have just that). Having it as a heat sink makes sense too, I guess. Not sure if my logic is correct but here's an analogy: if you fly really fast (several Mach) in a conventional-ish plane the tip of the wings will heat up and most likely melt before the thicker part of the wing does. So, maybe they are trying to do just that with the nose cone by putting fuel in there?

Liquid propane can be stored at room temperature in an strong steel or composite tank. Butane is even lower so its used in lighters and the thin walled tanks common in camping stoves. 
note that butane is an liquid at cold temperature, that is an downside of the cheap camping stoves and why lighters don't work if cold. 
Methane is cryogenic, you can not hold it in an pressure container, yes some places its used for heating but then its piped. 

All have an interesting property if heated. It tend to blow up very spectacular making them the most dangerous stuff in common use who can blow up, high explosives tend to be very safe, gunpowder is close but need higher temperatures and is less common in bulk, and yes gun store and fire ranges holding hundreds of kg of gunpowder has special rules especially if stored in bulk and not in cartridges. 

Having liquid methane with an common bulkhead with liquid oxygen sounds more energetic. 
For fun have the common bulkhead fail first  
 

 

[Raven Industries]

So the first colonists sent to Mars will be facing some sort of combination of the Oregon Trail on steroids, Amundsen's South Pole expedition, and an extended tour of duty in a submarine.