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Starship Prototype Unveiled

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Re: Starship Prototype Unveiled

#321

Post by ben_w »

DennisP wrote: post #311
ben_w wrote: post #247

Earlier quoted context omitted.

> Why people don't have to trust us: because the technology isn't physically capable of maintaining even that low energy density at the target, without the reference signal from the ground. From what I see that’s a design choice not a fundamental aspect of reality, but even if it isn’t: what stops a hostile actor creating their own guide signal, either to direct the power towards an vulnerable location, or to directe…

Sure, it's the physical design of the device. But that's a consequence of making something cheap from lots of small identical parts that self-assemble. You could make something that didn't require the reference signal, but it'd cost significantly more. And you could always allow inspections if people are really concerned. Changing the beam target would require a repointing of the satellite in addition to the new guid…

> Changing the beam target would require a repointing of the satellite in addition to the new guide signal.

I can believe either-or, not both. If a guide signal is important, antenna orientation isn’t; if orientation is important, guide signals are not.

> I'd like to see a real engineering cost estimate of transmitting power from one side of the planet to the other, by wires or any other method. I really doubt it can be done for four cents/kWh. And it would certainly introduce a possibility for hostiles to cause wide-scale power outages.

Do I have to? Geostationary is 36,000 km, pole-to-pole is 20,000 km over the surface. All I am claiming here is that any tech you use would also be able to solve my alternative more easily.

Re: Starship Prototype Unveiled

#322

Post by twic »

Symmetry wrote: post #313
twic wrote: post #265

Earlier quoted context omitted.

Musk does not design the rockets.

He doesn't do most of the work but he's very involved. Here's an interview Mueller gave that describes some things Elon did with the Merlin engine, search for "face-shutoff." https://zlsadesign.com/post/tom-mueller-interview-2017-05-02...

> And, uh, I’ve seen that hurt us before, I’ve seen that fail, but I’ve also seen— where nobody thought it would work— it was the right decision. It was the harder way to do it, but in the end, it was the right thing. One of the things that we did with the Merlin 1D was; he kept complaining— I talked earlier about how expensive the engine was. [inaudible] [I said,] “[the] only way is to get rid of all these valves. Because that’s what’s really driving the complexity and cost.” And how can you do that? And I said, “Well, on smaller engines, we’d go face-shutoff, but nobody’s done it on a really large engine. It’ll be really difficult.” And he said, “We need to do face-shutoff. Explain how that works?” So I drew it up, did some, you know, sketches, and said “here’s what we’d do,” and he said “That’s what we need to do.” And I advised him against it; I said it’s going to be too hard to do, and it’s not going to save that much. But he made the decision that we were going to do face-shutoff.

So, he knew about a problem, he heard someone mention a possible solution, and he insisted they use that solution.

That is not what designing is.

Re: Starship Prototype Unveiled

#323

Post by ryanmarsh »

anonytrary wrote: post #199
ryanmarsh wrote: post #166

How do they plan to get 100 tons of cargo from atop the starship down to the surface of Mars? Do you use a crane? I mean, cranes are heavy, right?

I think you're getting downvoted because of your flippant tone, but I am also curious how the cargo would get on/off the ship.

I have no idea how anybody read that as flippant. It was a sincere question. I’m about done with this community.

Re: Starship Prototype Unveiled

#324

Post by DennisP »

ben_w wrote: post #321
DennisP wrote: post #311

Earlier quoted context omitted.

Sure, it's the physical design of the device. But that's a consequence of making something cheap from lots of small identical parts that self-assemble. You could make something that didn't require the reference signal, but it'd cost significantly more. And you could always allow inspections if people are really concerned. Changing the beam target would require a repointing of the satellite in addition to the new guid…

> Changing the beam target would require a repointing of the satellite in addition to the new guide signal. I can believe either-or, not both. If a guide signal is important, antenna orientation isn’t; if orientation is important, guide signals are not. > I'd like to see a real engineering cost estimate of transmitting power from one side of the planet to the other, by wires or any other method. I really doubt it can…

The guide signal is what you need for a tight, coherent beam. Direction is up to the satellite, which can choose which of multiple receivers to target.

The advantage of transmitting power from space instead of the other side of the planet is that there's a straight line with no planet in the way. To go around the planet you need relay stations or wires. Plus there's the 5.4X more energy collected by each square meter of panel. So yes, some supporting evidence would be nice. Maybe even take a quick look at the NASA report I provided, too.

Re: Starship Prototype Unveiled

#325

Post by travisporter »

Paperweight wrote: post #136
afterburner wrote: post #110

Earlier quoted context omitted.

> Imo Elon is starting to get into contention for greatest engineer of all time. I don't know man, did he design it himself?

Meta-engineer? Engineering executive? At least he's trying to advance humanity instead of squandering it all on yachts like almost all the rest of the world's billionaires.

Is there a Woz behind Musk?

Re: Starship Prototype Unveiled

#326

Post by duckymcduckface »

twic wrote: post #322
Symmetry wrote: post #313

Earlier quoted context omitted.

He doesn't do most of the work but he's very involved. Here's an interview Mueller gave that describes some things Elon did with the Merlin engine, search for "face-shutoff." https://zlsadesign.com/post/tom-mueller-interview-2017-05-02...

> And, uh, I’ve seen that hurt us before, I’ve seen that fail, but I’ve also seen— where nobody thought it would work— it was the right decision. It was the harder way to do it, but in the end, it was the right thing. One of the things that we did with the Merlin 1D was; he kept complaining— I talked earlier about how expensive the engine was. [inaudible] [I said,] “[the] only way is to get rid of all these valves. B…

Mueller begs to differ "And now we have the lowest-cost, most reliable engines in the world. And it was basically because of that decision, to go to do that. So that’s one of the examples of Elon just really pushing— he always says we need to push to the limits of physics."

Re: Starship Prototype Unveiled

#327

Post by Ajedi32 »

woodandsteel wrote: post #190

It is going to be interesting to see what happens to SLS once SS/SH starts flying. I am guessing there is going to be big public campaign for NASA to cancel SLS and go with the SpaceX craft.

Yeah, I've been wondering about this too. In my opinion, it's been apparent for some time now that newer commercial launch providers are going to render SLS obsolete too early in its lifecycle for it to be worth the ongoing costs of continuing to develop it.

You might even argue that it's already obsolete, as despite it still potentially being the most capable rocket for some subset of missions, the per-launch costs are so high it might arguably be better to re-architect those missions to use multiple launches of a cheaper vehicle rather than launch on SLS. (You can launch 10 reusable Falcon Heavys for the cost of a single SLS launch.)

NASA/Congress has been stubbornly continuing to develop SLS despite that, but how much longer will they be able to hold out? Surely they won't be able to justify continued spending on SLS once there's another operational rocket that's both more capable in every respect, and a couple orders of magnitude cheaper to operate?

So at what point will they finally give up? Are they going to wait until after Starship hops? Until after it reaches orbit? Until after it achieves in-orbit refueling? Until after it lands on the Moon? Until after it lands on the moon, with crew? When?

Re: Starship Prototype Unveiled

#328

Post by abledon »

52-6F-62 wrote: post #17
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.

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 he prudent in maintaining good work habits? I hear the industry can be quite hard on people if they are not careful in how they work[1]

[1] https://www.thefabricator.com/article/safety/the-invisible-r...

Re: Starship Prototype Unveiled

#329

Post by simonh »

bushin wrote: post #320
simonh wrote: post #312

Earlier quoted context omitted.

Russia needs an oil price of at least $74/barrel to balance the budget, which means they've been in a lot of economic pain for the last 5 years. Roscosmos was seen as a cash cow, requiring minimal investment to make reliable $ income off their mature launch business. As a result they were starved of investment and are a pale shadow of their former selves. Building a dynamic, innovative organisation capable of develop…

it's $42/barrel, the difference from the market price goes into their war chest

I'm out of date. The Moscow Time says $49, but you're quite right in that Russia has done a lot in the last few years to bring their budget under control.

Their war chest is not looking too healthy though, the hit to oil prices in the last 5 years depleted a lot of their reserves. Thanks for the correction.

Re: Starship Prototype Unveiled

#330

Post by [deleted] »

fluffything wrote: post #240
strainer wrote: post #159

Earlier quoted context omitted.

From the sounds of it steel structure can basically handle much greater temperatures routinely and also even more in rare situations that might mean retiring the ship afterward but not losing everything. In his presentation Elon says that aluminum alloy or carbon fiber structure is basically done for at 300 to 400 Celsius, well that's the temperature at which stainless steel can just begin to get conditioned by heat,…

What do you mean by Handle? Steel won't melt at 300-400 Celsius but "handling" those temperatures for 10 minutes will change the properties of the material, possibly by a lot, so you don't need "melting" for structural collapse (Twin Towers style). As the GP says, if you put cold rolled steel, which has an elastic yield strength of >1500 MPa, at 300-400 Celsius, then it is only a matter of time (30-120 min) till the…

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