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Cont: Musk, SpaceX and future of Tesla II

GlennB said:
Interesting. What about the ship that provides the refuelling? Will that need refuelling in Earth-orbit in order to make it to the moon?
Genuine question. Sounds precarious, to say the least.
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It will be refueled twice but it will need about 20 Starship launches to get the fuel up there and then transferred from each Starship. Getting secure/reliable transfers will be quite an achievement.
 
As I understand it, the plan is for there to be a permanent refuelling station orbiting the Moon.

Here's how I believe it's supposed to go:

Starship A has a fuel tank and a cargo hold. It launches to orbit. Starship B has two fuel tanks. It refuels Starship A from one of them, which goes off to the moon. Starship B comes back to earth. Starship C has already fuelled up the refuelling station in Lunar orbit in a previous mission. Since fuel is only required for insertion and landing burns, Starship A should be able to both land on and launch from the Moon on one tank, due to the Moon's lower gravity. It refuels in Lunar orbit and returns to Earth. That's three launches in total for one successful Moon landing mission. If it requires a second refuelling prior to landing on the Moon, then a fourth mission will be required to restock the orbital station, but on reflection I don't think the second refuelling should be necessary.
 
arthwollipot said:
As I understand it, the plan is for there to be a permanent refuelling station orbiting the Moon.

Here's how I believe it's supposed to go:

Starship A has a fuel tank and a cargo hold. It launches to orbit. Starship B has two fuel tanks. It refuels Starship A from one of them, which goes off to the moon. Starship B comes back to earth. Starship C has already fuelled up the refuelling station in Lunar orbit in a previous mission. Since fuel is only required for insertion and landing burns, Starship A should be able to both land on and launch from the Moon on one tank, due to the Moon's lower gravity. It refuels in Lunar orbit and returns to Earth. That's three launches in total for one successful Moon landing mission. If it requires a second refuelling prior to landing on the Moon, then a fourth mission will be required to restock the orbital station, but on reflection I don't think the second refuelling should be necessary.
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It's not nearly that simple. Not by a long way.
From last year.
NASA lays out how SpaceX will refuel Starships in low-Earth orbit - Ars Technica https://arstechnica.com/space/2024/...lays-out-next-steps-for-starship-development/

Before getting to the Moon, SpaceX and Blue Origin must master the technologies and techniques required for in-space refueling. Right now, SpaceX is scheduled to attempt the first demonstration of a large-scale propellant transfer between two Starships in orbit next year.
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That didn't happen.

They need to demonstrate restarting engines in space. They did that but they've just moved on to a completely new design.

Since they don't have the heavy pump machinery in space that they have on the ground, the transfer of going to be done by the pressure difference between the two tanks. That won't be very efficient.

They have to be able to create a secure connection automatically between the two starships with no human intervention.
 
arthwollipot said:
It's actually a lot bigger. It's only a bit taller, but it is considerably larger in girth, and as we know that means volume.


Starship won't need to be refuelled "about twenty times". That's an exaggeration and you know it. It'll be refuelled once in Earth orbit and once in Lunar orbit for the return trip. Saturn V was also 100% non-recoverable and non-reusable. That alone increases Starship's complexity by orders of magnitude.


We don't know at this time what caused the explosion. I agree it was most likely a fault in the manufacturing.


I appreciate what SpaceX is trying to do. And I appreciate that they are doing as much testing as possible before putting people into this massive new kind of rocket. Musk is a ◊◊◊◊, absolutely. But if SpaceX can get this thing working it'll be a game-changer.
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And yet Musk recently admitted that Starship's estimated payload is one third of Saturn V's, 15 tons against 45.
 
arthwollipot said:
It's actually a lot bigger. It's only a bit taller, but it is considerably larger in girth, and as we know that means volume.


Starship won't need to be refuelled "about twenty times". That's an exaggeration and you know it. It'll be refuelled once in Earth orbit and once in Lunar orbit for the return trip. Saturn V was also 100% non-recoverable and non-reusable. That alone increases Starship's complexity by orders of magnitude.
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One of the big problems is that nobody really knows exactly how many refueling flights will be needed. However, you are the first person to estimate only two. Even the optimists are suggesting double digits.

Reusability is also a solved problem. Falcon 9 has a reusable booster and NASA were reusing orbital vehicles 40 years ago. The big question, however, is why is reusability required here for such a specialized mission. The answer is, of course, they need double digits launches to refuel the HLS.
arthwollipot said:
We don't know at this time what caused the explosion. I agree it was most likely a fault in the manufacturing.


I appreciate what SpaceX is trying to do. And I appreciate that they are doing as much testing as possible before putting people into this massive new kind of rocket. Musk is a ◊◊◊◊, absolutely. But if SpaceX can get this thing working it'll be a game-changer.
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jeremyp said:
Barely started on it? They were supposed to be on the Moon two years ago.
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We all know how much Musk exaggerates. It's nothing new.

jeremyp said:
Reusability is also a solved problem. Falcon 9 has a reusable booster and NASA were reusing orbital vehicles 40 years ago.
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Both are much smaller than Starship. I've stood in the VAB with a Space Shuttle. It's surprisingly tiny. If it weren't for the fence I could have reached out and touched the nosecone. Like I said, the sheer scale of Starship makes everything orders of magnitude harder.


Endeavour! by Andrew Gould, on Flickr
 
jeremyp said:
One of the big problems is that nobody really knows exactly how many refueling flights will be needed. However, you are the first person to estimate only two. Even the optimists are suggesting double digits.

Reusability is also a solved problem. Falcon 9 has a reusable booster and NASA were reusing orbital vehicles 40 years ago. The big question, however, is why is reusability required here for such a specialized mission. The answer is, of course, they need double digits launches to refuel the HLS.
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I think that's a little misleading. NASA's fastest turnaround for the reusable orbiter was 54 days. A Falcon 9 has launched again in less then two weeks, I think.

'Reusable' is on a scale, not something binary.
 
3point14 said:
I think that's a little misleading. NASA's fastest turnaround for the reusable orbiter was 54 days. A Falcon 9 has launched again in less then two weeks, I think.

'Reusable' is on a scale, not something binary.
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The orbital component is necessarily slower because it goes through a much tougher flight during re-entry.
 
a_unique_person said:
The orbital component is necessarily slower because it goes through a much tougher flight during re-entry.
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Oh, I agree. I'm just saying that something isn't either reusable or not reusable. It's a sliding scale. I believe some fairings are reusable. They just require fishing out of the water and completely refurbishing first. The space shuttle main engine was reusable. They just needed to take it completely to pieces and rebuild it...
 
arthwollipot said:
As I understand it, the plan is for there to be a permanent refuelling station orbiting the Moon.

Here's how I believe it's supposed to go:

Starship A has a fuel tank and a cargo hold. It launches to orbit. Starship B has two fuel tanks. It refuels Starship A from one of them, which goes off to the moon. Starship B comes back to earth. Starship C has already fuelled up the refuelling station in Lunar orbit in a previous mission. Since fuel is only required for insertion and landing burns, Starship A should be able to both land on and launch from the Moon on one tank, due to the Moon's lower gravity. It refuels in Lunar orbit and returns to Earth. That's three launches in total for one successful Moon landing mission. If it requires a second refuelling prior to landing on the Moon, then a fourth mission will be required to restock the orbital station, but on reflection I don't think the second refuelling should be necessary.
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Does that take into account the mass of the nuclear reactor to be landed on the moon?
 
The whole business appears to be extremely complex, expensive, and prone to utter failure over a minor glitch.
Can someone remind me why it's seen as a good idea?
 
GlennB said:
The whole business appears to be extremely complex, expensive, and prone to utter failure over a minor glitch.
Can someone remind me why it's seen as a good idea?
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Money. There are thousands of artificial satellites orbiting the earth. Each one cost a lot of money to put there, so there's profit to be made.
 
GlennB said:
Where's the money in a Starship lunar program?
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Currently in the pockets of US taxpayers?

A quick google gives:

"According to USA Spending, which tracks federal contracts, NASA has already paid approximately $2.7 billion to SpaceX for the "design, development, manufacture, test, launch, demonstration and engineering support" of the HLS."
 
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