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Starship Prototype Unveiled

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Re: Starship Prototype Unveiled

#61

Post by justapassenger »

cryptoz wrote: post #55
justapassenger wrote: post #51

Earlier quoted context omitted.

FH is "just" 3 F9 strapped together. Doing that took them more than 5 years than planned. Keeping that in mind, having 5 year delay on brand new design, using totally different materials, new engine, etc isn't far fetched.

There is a quote somewhere (by Elon?) saying that FH is not "just" 3 F9s strapped together. A significant source of the slowdown for FH was the desire to not launch it without full reusability of all 3 stages and not to launch it without significant improvements (block 5 etc). Starship has none of those potential delays and has already solved most of the hard problems (as evidenced by the Hopper hopping already). Sta…

Hopper shows that engine works outside of test lab. That's great, but it's far far away from showing that they solved most of the hard problems.

Experience from FH and F9 is useful, but it's a totally different type of spacecraft, with different use-cases, different materials, engines, cooling, etc. There's TONS of new stuff that they have to research, experiment, fail, try again, etc, until it's doing even 50% of what Elon promised.

Re: Starship Prototype Unveiled

#62

Post by brandonjm »

philwelch wrote: post #31

I suspect that Starship will fly to space before SLS ever will. I also think Starship has a significantly higher chance of flying at all than SLS.

It is certainly a little bold of Bridenstine to comment on other space companies being behind schedule given NASA’s own delays.

Re: Starship Prototype Unveiled

#63

Post by JorgeGT »

hansthehorse wrote: post #14
RandomTisk wrote: post #7

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.

I used to wander around the reactor auxiliary building at the nuclear plant I worked at and take pictures of the piping welds. They were works of art. The skill was obvious.

There's always https://www.reddit.com/r/Weldingporn/top/?t=all for nice pictures of welds.

Re: Starship Prototype Unveiled

#64

Post by cryptoz »

justapassenger wrote: post #61
cryptoz wrote: post #55

Earlier quoted context omitted.

There is a quote somewhere (by Elon?) saying that FH is not "just" 3 F9s strapped together. A significant source of the slowdown for FH was the desire to not launch it without full reusability of all 3 stages and not to launch it without significant improvements (block 5 etc). Starship has none of those potential delays and has already solved most of the hard problems (as evidenced by the Hopper hopping already). Sta…

Hopper shows that engine works outside of test lab. That's great, but it's far far away from showing that they solved most of the hard problems. Experience from FH and F9 is useful, but it's a totally different type of spacecraft, with different use-cases, different materials, engines, cooling, etc. There's TONS of new stuff that they have to research, experiment, fail, try again, etc, until it's doing even 50% of wh…

Perhaps I'm misunderstanding something. I thought Hopper was not about Raptor tests but about VTOL as well. The FH had to wait while F9 got down the vertical landing science and engineering (though a lot of tests, explosions, delays).

StarHopper seems like it can use those learnings, and that was tested recently. The engine was already functioning on a test stand and mated to Hopper for static fires; the Hopper hop itself is testing the engine, sure, but also the complex math of doing a vertical landing with a gimballing engine, etc.

The general space industry considered reusabable spacecraft that land vertically to be pretty much impossible until F9 and FH did it. But Hopper just does that casually, you don't bat an eye, you don't even comment that Hopper was testing a new rocket dynamics/physics for the math that (almost) only SpaceX has figured out.

I just don't see the pessimism here. I've been watching SpaceX for 12+ years and I don't see any of the same issues plaguing them today as did in the past.

New issues, but not the same ones. The new issues have dramatically smaller turnaround time to resolve.

The days of 5-year SpaceX delays are over.

Re: Starship Prototype Unveiled

#65

Post by vardump »

newguynewguy wrote: post #60
DennisP wrote: post #43

Earlier quoted context omitted.

It's the dawn of the true space age. And though Musk isn't a fan, this could even make solar power satellites economical. The monolithic designs from the 1970s would be absurdly expensive, but modern designs like SPS-Alpha get economies of scale by using lots of small identical parts that self-assemble in orbit. According to the book The Case for Space Solar Power , a 2GW satellite would deliver electricity at 15 cen…

Aren't there some pretty serious health and ecological problems with such large-scale microwave transmission?

Perhaps, but several orders of magnitude less bad than health and ecological problems from sunlight.

Re: Starship Prototype Unveiled

#66

Post by mattlondon »

codeulike wrote: post #8

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 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

#67

Post by baybal2 »

faead_ wrote: post #30
codeulike wrote: post #8

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.

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.

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

#68

Post by avar »

hoorayimhelping wrote: post #20

380s for ISP for the Raptor vacuum engine seems durn good, considering the tradeoffs between hydrogen and methane. The most efficient engines we've flown, the RL-10 [0] (used on the Delta IV and Atlas rockets as part of the Centaur Upper Stage) and the RS-25 [1], (the Space Shuttle Main Engine) get around 450-460s for their specific impulse. These engines use liquid hydrogen and liquid oxygen. The issue with liquid h…

> This is basically how SpaceX seems to operate: rather than optimizing a single part of the system (like trying to get the most efficient engine), they try to optimize from a systems level.

They're optimizing for "real" reusability, as in eventually aiming for airline-like turnarounds. None of the earlier engines you noted were reusable except the RS-25, and given how long it took to turn the Shuttle around one could argue it doesn't really count as "reusable" in sense SpaceX is aiming for.

Aiming for reusability and ease of maintenance leads to different optimization paths, in particular we should expect that any one component is going to be less powerful, it'll need to account for wear & tear, not use once and crash it into the ocean.

But raw performance on a single trip doesn't matter much if you can just deliver the same payload in two trips to orbit instead.

Re: Starship Prototype Unveiled

#69

Post by jcims »

_Microft wrote: post #40
allannienhuis wrote: post #34

Earlier quoted context omitted.

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 the…

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.

Re: Starship Prototype Unveiled

#70

Post by bluthru »

allannienhuis wrote: post #34
faead_ wrote: post #30

Earlier quoted context omitted.

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.

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 the…

And then you can make it a spiral of steel to eliminate the vertical welds.
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