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Re:Starship Prototype Unveiled by codeulike on Sunday September 29, 2019 @03:22PM (#21109109)
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.
Re:Starship Prototype Unveiled by mattlondon on Sunday September 29, 2019 @05:33PM (#21109741)
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 mean, is it just the outside that looks like that and inside it is ultra-exotic materials and tanks? Of course the engines are sophisticated machinery, but what about the insides? Are we just seeing the outer shell and it's all unobtanium nano-tube composite on the inside?

Re:Starship Prototype Unveiled by extrapickles on Sunday September 29, 2019 @05:42PM (#21109797)
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 by hinkley on Sunday September 29, 2019 @06:55PM (#21110145)
Steel can tolerate a lot more deflection before it bends, and much more stress before it cracks. And while I would never expect a space craft mechanic to employ this technique, any bike mechanic will happily offer to bend steel back into shape for you, but bent aluminum or carbon fiber is scrap. Bending it back will fracture it, if it hasn't already.

When Canondale hit the big time, they had one model year where they made the dropouts out of solid aluminum and in the next model year the derailleur hanger was bolted on. It's the easiest part to bend and there's no repairing it. Bad enough for road bikes, spectacularly dumb for mountain bikes.

Re:Starship Prototype Unveiled by balfirevic on Sunday September 29, 2019 @05:43PM (#21109800)
> 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 by hinkley on Sunday September 29, 2019 @07:00PM (#21110175)
I recall quite a while back, when titanium started first showing up outside of aerospace, that someone had created a titanium-titanium composite by layering plate titanium with titanium cloth and welding it together somehow. Was supposed to be stronger. Wonder if there's a steel equivalent possible.

I think the military was looking at a similar material to replace depleted uranium with something non-radioactive (depleted uranium still experiences alpha particle decay, which is fine if you don't aspirate or ingest it, but a shell can pulverize on impact with a target. Also it's still a heavy metal even if you don't take rads from it).

Re:Starship Prototype Unveiled by balfirevic on Sunday September 29, 2019 @08:12PM (#21110576)
> I think the military was looking at a similar material to replace depleted uranium with something non-radioactive

I thought the point of depleted uranium projectiles was simply the density of uranium, giving them large impact energy for a given volume. If that's the case, titanium (4.5 g/cm^3) will not even be as good as steel (8 g/cm^3), let alone uranium (19 g/cm^3).

Re:Starship Prototype Unveiled by MR4D on Sunday September 29, 2019 @10:34PM (#21111301)
Re:Starship Prototype Unveiled by nitrogen on Monday September 30, 2019 @12:48AM (#21111848)
I hope I am never in a position to hear that sound in person.
Re:Starship Prototype Unveiled by wuunderbar on Tuesday October 01, 2019 @02:20PM (#21128821)
Yea it's pretty wild. Although I am certain this is just for a prototype. I think the actual ones that will be sent to the Moon & Mars will be done in a clean room.
Re:Starship Prototype Unveiled by HenryKissinger on Sunday September 29, 2019 @04:44PM (#21109519)
Re:Starship Prototype Unveiled by chr1 on Sunday September 29, 2019 @05:56PM (#21109851)
Is the surface of these less smooth than surface of normal rockets/planes, or is it simply the effect of mirror like surface making bumpiness easier to see?
Re:Starship Prototype Unveiled by skykooler on Sunday September 29, 2019 @11:55PM (#21111656)
The latter - a matte surface would be lit from essentially the same angle, but even a tiny discrepancy causes big shifts in a reflection.
Re:Starship Prototype Unveiled by iamgopal on Monday September 30, 2019 @12:57AM (#21111893)
We work with multiple tens of ton of SS steel per month, and I would have never thought this heavy thing could fly with all the stress of the sky. I hope it fly good.
Re:Starship Prototype Unveiled by Florin_Andrei on Sunday September 29, 2019 @05:50PM (#21109827)
> 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 by de_watcher on Monday September 30, 2019 @03:28AM (#21112579)
Scrapped together plates make you wonder how it won't fall apart on ascent or descent...
Re:Starship Prototype Unveiled by faead_ on Sunday September 29, 2019 @04:26PM (#21109415)
he addressed in presentation, from what i remember it had a lot to do with cost. Like $130k/ton with carbon vs $3k/ton with steel. He mentioned a few other factors. Also it allowed them to build outside, not sure if t that is true in production.
Re:Starship Prototype Unveiled by emilecantin on Sunday September 29, 2019 @08:34PM (#21110715)
As he said in the presentation, it was because at cryogenic temperatures (which is the important part when you're building a liquid oxygen / methane tank) 301 stainless is actually _stronger_ than Al / carbon fiber. It also handles heat much better, which allows you to have a much thinner heatshield.

Both characteristics combine to give a lighter rocket than one built out of Al / carbon fiber.

The price is just the cherry on top.

Re:Starship Prototype Unveiled by allannienhuis on Sunday September 29, 2019 @04:34PM (#21109455)
the material isn't the question, it's why they had to weld it together in a patchwork quilt. Elon talked about the next version would simply have rolled coils with a single seam weld (although the cylinders would have to be welded together too), which would be better structurally and cosmetically, and likely lower cost of production. Sounds like they just didn't have the rolling machines to do the job, or perhaps there was an availability issue with the specific alloy.
Re:Starship Prototype Unveiled by _Microft on Sunday September 29, 2019 @04:41PM (#21109503)
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 use rolls twice as wide and only a single vertical weld each, then that's 500m between the rings and 50m for a single vertical seam. 550m of welds there instead of 1.5m before. This should speed things up quite a lot and reduce the cost of labour.

Raptor production is the real bottleneck, though.

Re:Starship Prototype Unveiled by x3n0ph3n3 on Sunday September 29, 2019 @07:52PM (#21110456)
The way I understood the presenation, they plan to use a single piece of steal, bent at an angle and rolled around (think one of those Pillsbury roll cans) with a single weld seem, in a giant helix.
Re:Starship Prototype Unveiled by jcims on Sunday September 29, 2019 @05:34PM (#21109751)
>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.

Re:Starship Prototype Unveiled by JshWright on Sunday September 29, 2019 @05:46PM (#21109808)
They just shipped he 12th one. Definitely still in the development/ramp up process.
Re:Starship Prototype Unveiled by de_watcher on Monday September 30, 2019 @03:30AM (#21112592)
He said that it's about one per week. One per day will be in several months.
Re:Starship Prototype Unveiled by emilecantin on Sunday September 29, 2019 @08:38PM (#21110743)
> although the cylinders would have to be welded together too

No, they'll do a helical weld, exactly like large pipes (like this: http://www.xysteelpipe.com/upload/201512118145340710.jpg)

You basically need to do that as the steel rolls off the press, though, which is why they didn't do that for Mk I. They'll need to cold roll the steel onsite.

Re:Starship Prototype Unveiled by 4684455 on Sunday September 29, 2019 @10:51PM (#21111383)
They will not do a helical weld because the steel's thickness varies from the top to the bottom of the cylinder, according to Elon Musk. https://twitter.com/HarryStoltz1/status/1162595874561617920 https://twitter.com/elonmusk/status/1162601447235604480?lang...
Re:Starship Prototype Unveiled by bluthru on Sunday September 29, 2019 @05:36PM (#21109764)
And then you can make it a spiral of steel to eliminate the vertical welds.
Re:Starship Prototype Unveiled by elihu on Sunday September 29, 2019 @06:04PM (#21109895)
He also talked about how stainless steel has a high melting point (which means their re-entry heat shield doesn't need to be as thick) and gets stronger rather than weaker at very low temperatures.
Re:Starship Prototype Unveiled by baybal2 on Sunday September 29, 2019 @05:34PM (#21109745)
Imagine the autoclave the size of a rocket.

Composite tanks on few rockets being flown with them are made in one of a kind, purpose built autoclaves

Re:Starship Prototype Unveiled by greglindahl on Sunday September 29, 2019 @08:47PM (#21110796)
Out-of-autoclave methods are mature and common these days.
Re:Starship Prototype Unveiled by baybal2 on Monday September 30, 2019 @04:06AM (#21112769)
Do they get you the same strength, fill ratio, and allow for usage with aerospace specialty epoxies?