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Starship V3

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Re: Starship V3

#581

Earlier quoted context omitted.

There is also zero evidence to oppose it. We know some things from experience about the long term (1 year or so) effects on human health of 0g (tl;dr: not good). We know very very little about the long-term effects of 0.166g on human health, because it's never been done. (best guess: also not good).

> There is also zero evidence to oppose it. That's how reason works. "You can't prove there isn't a silver, bubblegum-farting unicorn living on the asteroid belt" doesn't make it true. Nor more plausible.

Thank you for your restatement of Russell's teapot (1). As an aside that's about unfalsifiable claims and the burden of proof, not logic in general.

But the idea that this is "Nor more plausible" is wrong - there are good reasons to believe that human health and development that has occurred under 1g throughout our entire evolutionary history could go wrong when deprived of that, is in fact a highly plausible idea.

The "extraordinary claim" would be that there is no impact on human health and development from living entirely in (for example) lunar 0.16g.

I'm all for looking into it getting the data, but no space agency has yet constructed the required fractional G rotating structure. Nasa has made plans, see e.g. Nautilus-X (2) and AGOS study (3) but nothing has yet been built "due to budget constraints".

1) https://en.wikipedia.org/wiki/Russell%27s_teapot

2) https://en.wikipedia.org/wiki/Nautilus-X

3) https://www.researchgate.net/publication/319164912_AGOS-Arti...

> By changing the rotation rate AGOS Stage 1 can be used as a testbed for different g-levels and their influence on human health.

Re: Starship V3

#582

Earlier quoted context omitted.

If that's one of the better criticisms of the book, that's a pretty good recommendation for the book. The article author clearly just doesn't like their dream being shattered.

As I said, "doesn't get it." Neither the Weinersmiths nor you seem to understand the motivations of people that actually want to settle Mars. EDIT: It was just pointed out to me that the meat of Peter's review (parts 2 & 3) are paywalled. What I linked to was more like a summary for a review. Sorry. Space fan: We're going to make a city on Mars! Weinersmith: It's going to be hard. There is no air, the ground is toxic…

  > It's going to be hard. There is no air, the ground is toxic, an insane amount of constant work will be required just to stay alive.
I'll go! I'll happily go to die a painful, slow, torturous death on the way to Mars, so that humanity learns what to do differently for the next crew. I'm so enthusiastic about the prospect that even my kids know, given the opportunity, I would kiss them all one final goodbye and happily launch towards the red wandering bright dot in the night sky.

I'm a successful developer, not suicidal, generally happy person. And I've dreamed of such a mission for decades.

There may not be many people like me willing to make such a sacrifice, but it only takes a handful of us to help propel our species further.

Re: Starship V3

#583

Earlier quoted context omitted.

Plus insane storms and winds that I’m not sure Antarctica will properly simulate.

Those "insane storms and winds" in an atmosphere with 2% of the density of earth's atmosphere won't be much of a problem.

It will be when it covers your solar cells with dust.

Re: Starship V3

#584
post #530

Earlier quoted context omitted.

There is also zero evidence to oppose it. We know some things from experience about the long term (1 year or so) effects on human health of 0g (tl;dr: not good). We know very very little about the long-term effects of 0.166g on human health, because it's never been done. (best guess: also not good).

> We know some things from experience about the long term (1 year or so) effects on human health of 0g (tl;dr: not good). But we don't know anything about the long term effect of 0g on human fetuses, which live in a very different environment than the humans we have tested. They live in an environment that combines fluid immersion and surface support, with buoyancy playing a major role -- which could (or could not --…

> I'd be more concerned about the impact of zero and low gravity on newborns than fetuses

I agree with that. If (and it's if) it turns out that zero and low gravity are OK for foetal development, then there's the around 20 years of development that comes after birth and before adulthood, where "fluid immersion" is not part of the normal development process.

Re: Starship V3

#585
post #564

Earlier quoted context omitted.

For reference: Starlink is Unless it manages to massively eat into mobile network market share (pretty unlikely in my view) growing past $100bn (yearly revenue) or so seems unrealistic to me. Even with cheaper launch costs, it is not clear to me that Starlink would ever be interested in offering service for like $80/year (=> price competitive with mobile carriers in low income nations).

> Unless it manages to massively eat into mobile network market share Several mobile carriers are already using them for backend of remote towers.

For something relevant? Why would they do this? Dark fibers is an easy thing and you need to put power to these remote towers anyway.

Re: Starship V3

#586
post #482

Earlier quoted context omitted.

It’s very easy to overestimate the difficulty of cooling things in space, unless you actually run the numbers. So please follow along as Scott Manley runs the numbers: https://www.youtube.com/watch?v=FlQYU3m1e80 >. Basically a Starlink v3 satellite has an estimated power budget of 20kW. Add in the heat absorbed from the environment (both directly from sunlight and reflected off of the Earth) and you’ll find that it m…

I'm not rejecting the basic idea in itself. There is nothing in this idea which we as humans can't do today. No issues here. Its just so much more expensive than just doing it in a dessert and putting fibre and solar panels and batteries there. The Starlink v3 doesn't exist yet in space, it also needs Starship apparently and Musk said it will have the size of a Boeing 737 fully deployed. So it will not be small and i…

> The Starlink v3 doesn't exist yet in space, it also needs Starship apparently

True but not really relevant. All prior versions of Starlink worked well enough, so there’s no reason to suspect that v3 won’t.

> … it will have the size of a Boeing 737 fully deployed. So it will not be small…

Irrelevant. Size is a weird measure here. You should ignore it because it is a marketing thing. All that is meant by it is that once the solar panels are extended they span a distance larger than the wingspan of a 737, nothing more. A Starlink v3 satellite has far less mass, interior volume, or complexity than a 737. I could get a long 30m rope and tell you that it was “larger than a 737”, but you wouldn’t be very impressed.

> A rack with 48u will either have 12 or 24 GPUs which equals to 9kW or 17kW. Than its not 250k satellites for a 'small' 300MW DC but only 25k. Still a very crazy number.

Are you sure? That fits within the estimated power budget of a Starlink v3, but I was assuming that GPUs were denser than that these days. I’m not an expert though. I figured a rack would hold somewhere between 96 and 128 GPUs depending on whether they had to be in 3u or 4u servers. They would need between 60kw and 90kW of power, and would need a modest radiator. The solar panels would be far larger than the radiator.

> I would love to see all of this scifi stuff happening. Spaceship in space, travel gates, dyson sphere but there is just no current breakthrough in our society which would indicate that this makes sense.

Ok, see, your problem is that you haven’t properly distinguished between different types of fiction. You put those three things in one category as if they were all equally fictional, but that cannot be true.

The first one is ambiguous, since the Space Shuttle was definitely a “spaceship in space”, so perhaps you just mean FTL travel like in Star Trek or Star Wars. By “travel gates” I assume you mean something like the eponymous gates from Stargate SG–1. Those are both ruled out by the laws of physics, and we can only tell stories about them because people willingly suspend their disbelief. Campbell said that a true science fiction story can only include one thing that requires the reader to suspend their disbelief. If it includes more than that then it is a fantasy instead.

But a Dyson sphere, or more accurately a Dyson swarm, is not an impossibility at all. If I can put one solar–powered satellite in orbit around the sun then if I am really industrious I could put ten, or a hundred, or a trillion. As many as I wanted and could afford, right? The laws of physics don’t say that a sun can only have 8 satellites around it, or any other number. Dyson knew that enough such satellites would eventually blot out the sun. They would absorb all the sunlight it could emit, and then the satellites would all emit infrared waste heat. If all of those satellites were doing something useful then whoever put them there would have a lot of useful work being done at their command. Even if it’s just trillions of GPUs making AI–powered cat memes, or simulating the minds of a bunch of human uploads, or even if they’re all just mirrors to redirect that light somewhere else, that’s a lot of power at our command. It is fictional only because it is an idea that nobody has actually gotten around to implementing yet. Once we’ve done it then it won't be fictional anymore.

> Its just so much more expensive than just doing it in a dessert and putting fibre and solar panels and batteries there.

No one here is arguing that it isn’t. It might still be cheaper to build datacenters on Earth. But most of the people who say that it’s _definitely_ still cheaper to build them on Earth are overestimating the difficulties, and therefore the costs, of doing it in orbit instead. We’re getting to the point where launch costs are low enough that it is no longer a given that it is cheaper.

For one thing, actually building things in the desert is expensive. You have to build all the necessary infrastructure yourself. Roads, power, water, fuel, etc, etc. You might as well be launching everything into space! No, if you want it to be cheaper you need to build somewhere closer to home, like Ohio.

Re: Starship V3

#587
post #539
post #482

Earlier quoted context omitted.

It’s very easy to overestimate the difficulty of cooling things in space, unless you actually run the numbers. So please follow along as Scott Manley runs the numbers: https://www.youtube.com/watch?v=FlQYU3m1e80 >. Basically a Starlink v3 satellite has an estimated power budget of 20kW. Add in the heat absorbed from the environment (both directly from sunlight and reflected off of the Earth) and you’ll find that it m…

What doesn't make sense to me here is that even on Earth, where we have an atmosphere to disperse heat into, we find that closed-loop cooling is too expensive and so use evaporative cooling. If the economics make it too expensive not to use freshwater on Earth, I don't see how closed-loop cooling suddenly becomes affordable in space where dispersing heat is already more difficult.

Here in datacenters we use cooling systems to move heat away from the computers and out of the building. If each rack in the data center were outdoors and 100 yards away from every other then almost no cooling would be required. Just some fans to suck in air at the bottom and eject it out the top. Even less would be required if the individual GPUs were somehow separated from each other. Then we would truly be dispersing heat into the atmosphere with no cooling system at all.

Similarly, a satellite only needs a cooling system so that it can move the heat from the internal components outward towards the hull. A satellite containing a rack’s worth of GPUs might literally have heat spreaders that touch the chips on one side and the outer hull of the satellite on the other. Combine that with some heat pipes or something to spread the heat out efficiently and you hardly need anything else. A satellite the size and shape of a Starlink v3 already has enough surface area to dissipate something like 28kW at 80°C, and more if you run it hotter. If you want more than ~30–40 GPUs per satellite then you might need a small radiator to increase the surface area, or you might just make the thing thinner and wider instead. You’ll need more solar panel area anyway, so making the bus wider to match the wider solar panels is fine. The “closed–loop cooling system” you say is so unaffordable might be no more than a bunch of heat pipes. Or it might be an aquarium motor that pumps a few kilos of ammonia through some pipes or channels in the hull of the satellite.

Re: Starship V3

#588

Earlier quoted context omitted.

If it’s not that hard, then perhaps someone can just point to the simple math of how it would work. It’s not like only idiots who know nothing about space are pointing out the cooling issue: https://taranis.ie/datacenters-in-space-are-a-terrible-horri...

The problem is, that person is deeply underinformed. For instance: "you don't lose that much power through the atmosphere" Assuming you can point the orbiting panels at the sun and remain direct, you lose 80% of your power through the atmosphere (from angle and day/night). On the ground you lose 25% even if your panel is directly below the sun pointed exactly at it, which is never the case in many latitudes. And of c…

Don’t get me wrong, space data centers will happen, but as usual, Elon’s timeline is total bullshit.

Re: Starship V3

#589

Quick update for the folks passionate about space things (since this thread is full of unrelated comments): V3 is their first Starship family big upgrade, containing lots of learnings from previous tests, and the big engine upgrades. V3 engines are the first iteration of a production engine, with lots of sensors and auxiliary systems integrated into the engine itself. Besides the improvements in thrust, they've strea…

> They've also updated the launch tower, with a flame deflector, and a new deluge system.

So much insane engineering just to make this launch pad work. The pad is more complex then the rocket. To make something that survives repeatedly the insane power of Starship is a actually insane.

That they managed to do a full duration static fire and it seems the pad is ok is a huge achievement.

Re: Starship V3

#590
post #565

Earlier quoted context omitted.

Heat, maintenance...it's obvious if you think about it for 2 seconds.

> maintenance I suspect it would be maintained at the same quantization that it's delivered: pods. Pod has some unresolvable issue (things would have to go real bad), then eject it. What maintenance do you have in mind, specifically, in a modular system like this would necessarily be? If the argument is that off the shelf systems, designed within a context where humans are a Jira ticket away, won't work well in space…

And you are right that is possible. But the question is not, 'can you build a data-center in space', but rather is it cheaper to build it in space?

A data-center no matter where has 100'000s of connections, each connection is a failure point. And things that go on rockets that shake to an insane degree need to have lots of special attention paid to each such connection.

Heating again is 10-100x more difficult in space, again, it could be solved, but again, is it cheaper.

Same for transport, transporting stuff into space is 10-100x more expensive.

Same for lifecycle management, 10-100x more expensive in space. You need fuel and move around avoiding collisions and so on.

Same for mechanical complexity overall, a standard server rack on earth is complex (see Oxide) a 'space server rack' is likely 10x100x more complex.

So basically you have to re-engineer literally everything from the ground up for a new environment.

So the question is what is the argument for why you should bare this cost. The only argument seem to be constant sunlight, and maybe regulatory. Regulatory is not looking like it will be much easier in space, launch alone is a huge regulatory burden.

So really we are comparing setting up enough batteries to survive for a night or getting another constant source of power with all the cost mentioned above. I know what side I would be on.

> active rerouting around dead cores

That still means you have a dead core in your system. All you are saying is 'lets pay even more to launch extra capacity in case part of it fails'. And that goes for every part from the smallest core all the way up to the largest subsystems on the sat.

Or you can just order a replacement when you actually need it, like when you have a data-center on earth.

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