Cont: Musk, SpaceX and future of Tesla II

[GraculusTheGreenBird]

And your point is? Sometimes (quite often actually) things don't go entirely according to plan. The Cybercab won't enter production until next year, and then will need months of testing before it goes 'live'. Meanwhile Tesla is just using production Model Y's - currently with safety passengers but this will soon change. For whatever reason they haven't managed to get 500 of them out so far. I don't know what the holdup is, but considering that they have only been trialing their robotaxi service for a few months I don't think it's a big deal. Tesla has typically been very cautious about introducing new products. The Cybertruck was trialed for 4 years, and the Semi for nearly 3 years now.

Tesla doesn't need 'saving'. Their push into robotaxis and robots is unneccessary at present, and is actually quite risky. But you don't get real innovation without risk. Many other companies are pouring billions into similar projects. Some, like Google, are continuously losing money without much progress. Others haven't produced anything at all. The company that first 'cracks' these technologies stands to win big. But 'winning' isn't Musk's goal - he's interested in what the technology will do for us, not the profit that could be made. That's why he's willing to take risks that others aren't. You can bet that Tesla will continue to put as much effort as they can into pushing the boundaries, which is a good thing.

But of course you don't care about that. It's all about cancelling Musk because he's a Bad Person^TM. Yeah he's not perfect, but neither were many of the great innovators of the past. If liberals hadn't taken an immediate dislike to him over irrelevant issues he might not have veered right like he did. But other automakers are sucking up to the Trump administration too, for obvious reasons. Perhaps if Democrats hadn't snubbed Tesla, who was actually helping them achieve their goals, Trump wouldn't be President now and Musk would be sucking up to Harris instead. Harris even admitted recently that giving Tesla the cold shoulder was a mistake.

The point is, as always, that musk is a liar, a cheater and a ◊◊◊◊◊◊◊◊◊◊◊. And you, for some unfathomable reason, continue to defend him when he lies and cheats and bullshits. I assume you think these traits are praiseworthy? Or only when it comes to musk?

One can clearly hold an opinion regarding his obvious lies, cheats and ◊◊◊◊◊◊◊◊ without needing to comment on his politics. The reason he is in fact demonstrably a bad person, is because he is a liar, a cheater and a ◊◊◊◊◊◊◊◊◊◊◊.

Oh, and of course Tesla has lost the EV battle, and will never be anything other than an also ran now. Because of his lies and ◊◊◊◊◊◊◊◊. Like the hyperloop ("Honestly, its not that hard!"). Like the boring company. Like the semi. Like the new roadster. When you can't deliver on anything but lies, that tends to be the result, falling market share.

ETA no idea why one particular bovine excrement reference made it through the censor, but the others didnt.

 

[arthwollipot]

ETA no idea why one particular bovine excrement reference made it through the censor, but the others didnt.

Apparently ◊◊◊◊◊◊◊◊ and ◊◊◊◊◊◊◊◊◊◊◊ are in the censor's database but bullshits is not.

 

[jeremyp]

Sure, why not?

My point is that solving the pressure problem is not difficult.

You'd better let all those engineers at NASA and SpaceX know that then.

How about this one: the target tank is evacuated. Dock a high pressure fuel tank with one that contains a vacuum and the fuel will flow from one to the other.

Until the pressure in both tanks is equalised. That's the exact problem everybody here is talking about.

And It's worse than that because as soon as the source tank has a little bit of space in it, the fuel will start to turn to gas and that gas is useless for running rocket engines but you'll need to stop it from going into the target tank because it'll just take up space. On Earth that's an easily solved problem: you just put the hole at the bottom and the gas goes to the top. There is no bottom in space.

And the reason we haven't seen it done yet is that in order to do it, Starship actually has to be able to get to orbit.

Well, that's one of the reasons. It's not like other rockets haven't gone into space and it's not like the idea wouldn't have been useful for other missions in the past.

 

[arthwollipot]

You'd better let all those engineers at NASA and SpaceX know that then.

I'm sure they already know. They're smart.

Until the pressure in both tanks is equalised. That's the exact problem everybody here is talking about.

It's a solved problem.

And It's worse than that because as soon as the source tank has a little bit of space in it, the fuel will start to turn to gas and that gas is useless for running rocket engines but you'll need to stop it from going into the target tank because it'll just take up space. On Earth that's an easily solved problem: you just put the hole at the bottom and the gas goes to the top. There is no bottom in space.

I'm sure there's a way around that. I believe the phase transition of materials depends on two factors - pressure and temperature. If the pressure goes down, turn the temperature up. Or something. Like I said, I'm not an engineer.

Well, that's one of the reasons. It's not like other rockets haven't gone into space and it's not like the idea wouldn't have been useful for other missions in the past.

Possibly, but it's never been needed before. Previous rockets have all carried their own fuel. That's always been part of the problem.

 

[jeremyp]

And your point is?

My point is that Tesla is in deep trouble.

Sometimes (quite often actually) things don't go entirely according to plan.

At Tesla things often seem to be going entirely not according to plan.

The Cybercab won't enter production until next year,

Is that an Elon year or a human year?

and then will need months of testing before it goes 'live'. Meanwhile Tesla is just using production Model Y's - currently with safety passengers but this will soon change.

You mean a safety driver. Will it change soon? How soon? What's your evidence for it ever changing at all?

For whatever reason they haven't managed to get 500 of them out so far.

That's a bit odd isn't it? They've got all these model Y's they can't sell and yet they can't find 440 to put on the roads of Austin as autonomous taxis.

I don't know what the holdup is, but considering that they have only been trialing their robotaxi service for a few months I don't think it's a big deal. Tesla has typically been very cautious about introducing new products. The Cybertruck was trialed for 4 years, and the Semi for nearly 3 years now.

This is utter unadulterated ◊◊◊◊◊◊◊◊. We know Tesla is not cautious because they released FSD before it was even remotely ready. The reason they couldn't make Cybertruck and theSemi to the original schedule is not caution but because they didn't really exist when they were announced and it turned out that it is very hard to make a product to spec when the spec was pulled out of Elon Musk's arse.

It looks like Tesla will be setting a world record for caution with the Roadster, which you forgot to mention.

Tesla doesn't need 'saving'. Their push into robotaxis and robots is unneccessary at present, and is actually quite risky.

Yes it is unnecessary. Tesla used to make quite good cars but they dropped the ball on that to nudge in Musk's flights of fancy.

But you don't get real innovation without risk. Many other companies are pouring billions into similar projects.

And they are mostly way ahead of Tesla. Waymo already has more than 200 autonomous taxis in Austin and they don't need a driver to sit in the passenger seat for when they go wrong.

It's all about cancelling Musk because he's a Bad Person^TM.

He is a bad person but he's a bad person that's destroying a previously good car company. He's also a liar of the first order and he will say anything to make a buck.

Yeah he's not perfect, but neither were many of the great innovators of the past. If liberals hadn't taken an immediate dislike to him over irrelevant issues

Shutting down USAID and taking a chainsaw to other parts of the US government are not irrelevant issues.

he might not have veered right like he did. But other automakers are sucking up to the Trump administration too, for obvious reasons. Perhaps if Democrats hadn't snubbed Tesla, who was actually helping them achieve their goals, Trump wouldn't be President now and Musk would be sucking up to Harris instead. Harris even admitted recently that giving Tesla the cold shoulder was a mistake.

You realise you are excusing Musk for buying an election here.

 

[jeremyp]

I'm sure they already know. They're smart.


It's a solved problem.

How has it been solved. How has the problem of moving a pressurised volatile liquid from one tank to another been solved when you don't have the help of gravity? Can you show me any working solution?

I'm sure there's a way around that. I believe the phase transition of materials depends on two factors - pressure and temperature. If the pressure goes down, turn the temperature up.

How do you turn the temperature up on 100 tonnes of liquid methane in space? I'm not saying it can't be done but I'm asking for an engineering solution. If you haven't got one, you are just hand waving.

Or something. Like I said, I'm not an engineer.

Has it not occurred to you that, as a non engineer, you don't understand the problem to at the level required to understand how hard it is?

Possibly, but it's never been needed before. Previous rockets have all carried their own fuel. That's always been part of the problem.

That's the point. Your spacecraft can be heavier and more capable if you send the fuel up separately and put it in once in orbit. Yet, they didn't do that even for the Apollo missions. Guess why not.

 

[Andy_Ross]

Why not transfer the whole tank?
Attach it to the outside when in orbit, like aircraft drop tanks?

 

[arthwollipot]

How has it been solved. How has the problem of moving a pressurised volatile liquid from one tank to another been solved when you don't have the help of gravity? Can you show me any working solution?

 

[a_unique_person]

SpaceX is pumping cryogenic propellants around their sites all the time. But doing so on orbit will probably be slightly different. Or a lot different. I've no idea if they are planning to do so.
You can, of course, accelerate the transfer by pressurizing the supplying side, as with an inert gas. They do some of that anyhow during launches. It gets trickier in zero-G, so you may have to apply a slight acceleration to keep the stuff where you want it.

They have to take that inert gas up there too.

Having two starships accelerating equally while connected and transferring cryogenic liquid.

How does a piston fit in a very carefully crafted container rather than a cylinder?

They are rocket engineers. They have gone for the simplest option rather than a more complex one. Maybe that is Musk's doing. He has made 'simplification' his mantra.

 

[Darat]

View attachment 66653

Doesn't that example require gravity?

 

[arthwollipot]

Doesn't that example require gravity?

To get the water out, yes. That's its purpose. But to pump it up requires going against the gradient, demonstrating that it really isn't that hard to pump liquids against a gradient, whether that be gravity or pressure.

 

[dirtywick]

the supply pump is also being fed by gravity though

 

[arthwollipot]

the supply pump is also being fed by gravity though

Well, how about this?



Using nothing but the movement of air, this machine, ubiquitous in the Australian outback, draws groundwater up to the surface, against gravity, using nothing but basic mechanical parts.

My point is that a pressure gradient should not be a problem. The bigger problem is getting Starship to orbit.

 

[dirtywick]

Well, how about this?

View attachment 66663

Using nothing but the movement of air, this machine, ubiquitous in the Australian outback, draws groundwater up to the surface, against gravity, using nothing but basic mechanical parts.

My point is that a pressure gradient should not be a problem. The bigger problem is getting Starship to orbit.

the groundwater is under gravity. just take any pump design you can imagine, the supply line from the reservoir is always at the bottom of the tank. try imagining how it would work if it was at the surface of the reservoir instead

point is you need some way to keep the supply pump primed.

idk anything about space

 

[3point14]

When starting an engine in orbit (other than a hypergolic motor), requires ullage motors (usually hypergolic) to ensure the fuel is where the pump can get at it. Then, once the engine is fired, the fuel is going to be pressed against the back of the craft, creating an artificial gravity. You can't do this when pumping fuel rather than firing a rocket.

Ultimately, it may be easier to just spin one spacecraft around the other on a tether and let 'gravity' do it's thing than to try to pump fuel out of a tank that it's just floating around in.

 

[Andy_Ross]

Transfer the tank

 

[3point14]

Transfer the tank

Which adds weight, both the tank and whatever kit you need to transfer it. Then you need to ensure it's properly connected.

I've done this in KSP - it's a total pain in the backside. And KSP is much, much easier than real life.

 

[Andy_Ross]

The recieving ship doesn't have to worry about weight once it's in orbit.
When it returns the tanks can be let go.
Like aircraft drop tanks.

 

[3point14]

The recieving ship doesn't have to worry about weight once it's in orbit.

It does. More mass = less ∆V

But more than that, I think, is that the donor ship absolutely does have to worry about mass, both in terms of ∆V and thrust to weight ratio.

 

[jeremyp]

Well, how about this?

View attachment 66663

Using nothing but the movement of air, this machine, ubiquitous in the Australian outback, draws groundwater up to the surface, against gravity, using nothing but basic mechanical parts.

My point is that a pressure gradient should not be a problem. The bigger problem is getting Starship to orbit.

Pumps need energy. Where is that coming from in space? Bear in mind we are talking about a lot of liquid - a hundred tonnes maybe - under high pressure.

The bigger problem though is making sure you pump liquid rather than gas. The wind pump in your picture works very nicely if the bottom end of the pipe is under water. If it's not under water, how much water is it going to pump? None. When you are on Earth you can rely on gravity to make the liquid sit over your pump's intake. When you are in orbit you can't do that. The liquid just floats around the tank anywhere, unless the tank is completely full.

As 3point14 points out, this problem is usually solved with an ullage motor which get the spacecraft accelerating, so the fuel all moves to one end and can then be pumped to the main engines to restart them. Refuelling with an engine firing seems to me to be quite a tricky concept to make work. Spinning the craft around each other also might work. Although as you pump fuel from one craft to the other, the centre of mass will change which might send the two craft into an uncontrolled wobble.

Another solution would be to make the tank out of a flexible material which can collapse like a balloon as the fuel leaves it. However, the flexible tank would have to sit in a space that can be pressurised with an inert gas to stop the fuel inside vaporising and inflating the tank. I think this is something SpaceX does on a small scale with the header tanks.