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Starship Prototype Unveiled

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Re: Starship Prototype Unveiled

#71
post #23

Earlier quoted context omitted.

How do you picture them rolling a piece of steel 50 meters wide? As far as I know, the widest rolling mills in existence are 5 meters wide.

Think of it like a paper towel tube. It's a spiral. Single helical weld.

Spiral tube are a bad choice for a rocket. Because rolled steel has the grains largely aligned with the direction of rolling, it is stiffer and has less thermal expansion in one axis than the other. Large forces and temperature changes therefore cause a twisting motion, which can put weird strains on the internal components.

Re: Starship Prototype Unveiled

#72

I totally understand why they've gone for that design but the welded together steel plates really make me think of the sort of thing Wallace and Gromit would build.

I am totally with you on this - I just can't get over how utterly rudimentary and basic this thing looks! I can't wait to see it fly! I am so used to seeing space stuff done in clean rooms, and things taking years and years to come to fruition (e.g. hearing about and seeing NASA or ESA probes etc getting made) that to see what is essentially a bunch of guys in a field just welding something together blows my mind. I…

I suspect most of the structure that gets really hot or cold is steel. To save weight, they are probably also letting more of the rocket get colder/hotter than normal, thanks to the wider temperature range of steel.

Once the temperatures get reasonable, it might be aluminum or or carbon fiber. The passenger/cargo/avionics section are probably the only areas where this would be true, so a bulk of the rocket will be steel.

Re: Starship Prototype Unveiled

#73

I totally understand why they've gone for that design but the welded together steel plates really make me think of the sort of thing Wallace and Gromit would build.

I am totally with you on this - I just can't get over how utterly rudimentary and basic this thing looks! I can't wait to see it fly! I am so used to seeing space stuff done in clean rooms, and things taking years and years to come to fruition (e.g. hearing about and seeing NASA or ESA probes etc getting made) that to see what is essentially a bunch of guys in a field just welding something together blows my mind. I…

> Are we just seeing the outer shell and it's all unobtanium nano-tube composite on the inside?

Nope, it's just steel. Outside shell is the tank.

Re: Starship Prototype Unveiled

#74
post #69

Earlier quoted context omitted.

It will reduce the length of the welds (for the hull) quite a bit. The number of rings is roughly 35 for Starship, with about ten vertical seams each. For easier thinking, line the vertical seams up and you see that this gives 50m length per vertical seam from bottom to top of Starship. So there are a total of 500m for that. 35 rings with ~28m circumference add up to about 1km of seams between them. Now if they can u…

>Raptor production is the real bottleneck, though. They are shooting for one per day, no? Based on the differences identified in the three hanging under the Boca Chica vehicle now, it’s still in development.

They just shipped he 12th one. Definitely still in the development/ramp up process.

Re: Starship Prototype Unveiled

#75

That was a very dense an informative presentation last night, but I think the main take away is that rapid reusability is a game changer. In fact, game-changer is probably an understatement, basically every intuition and rule-of-thumb we have about space launches and travel will have to be rethought. And this will be true even of SpaceX falls well short of meeting their stated targets (2020 orbit, 150t capability, mu…

"the world's launch capacity will be expanded by two orders of magnitude"

How will so many more launches impact the space junk problem?

From what I understand, there's already a catastrophe waiting to happen if some space junk collides with a satellite and causes a chain reaction of more space junk destroying more satellites, etc... until there's an impenetrable debris field around the earth.

Will having that many more launches and the potential accidents therefrom significantly increase the odds of such a catastrophe?

Re: Starship Prototype Unveiled

#76
post #38

Earlier quoted context omitted.

Starship could have Falcon Heavy level of delays (which I think it will) and still beat SLS.

Not entirely sure about that. Have no skin in the game but from what I can tell Starship is just a bigger version of the Falcon 9 second stage. FH on the other hand required a lot of engineering investment to figure out how to bolt three F9s together and how to make the software work between all three. I'm certain it will be a long time until it can get to Mars, but LEO within the next 2-3 years is probably realistic…

> I can tell Starship is just a bigger version of the Falcon 9 second stage

What similarities are you referring to? They're designed to be launched atop another, bigger rocket. Other than that...?

Re: Starship Prototype Unveiled

#78

I totally understand why they've gone for that design but the welded together steel plates really make me think of the sort of thing Wallace and Gromit would build.

> the welded together steel plates really make me think of the sort of thing Wallace and Gromit would build

The most beautiful thing in the world is success.

Re: Starship Prototype Unveiled

#79

Earlier quoted context omitted.

AFAIK it's uncommon skill, you need the steady hands of a surgeon to have a chance. Definitely not work I could do, I know that.

My dad did this kind of work in the oil industry for 30+ years as a pipe fitter. His specialty was stainless and they had to be x-ray perfect welds. He recently retired but was always very proud of his work. It took me a long time to understand why. I wish he could have gotten into the space industry vs oil refineries. The latter is much harder on a person.

> was always very proud of his work. It took me a long time to understand why.

I'm a mediocre amateur welder and I totally understand why.

Re: Starship Prototype Unveiled

#80
I just want to point out that SpaceX has not yet successfully put a human in LEO. The moon seems well beyond their technical capabilites at the moment and Mars seems like a fools dream at this point in time.
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