[Spaceships] SM+35 Toroid Station?

[DataPacRat]

Originally Posted by Anthony

Spaceships has its realism problems, and you're hitting some of them, but the realistic answer is "you can't actually build something like that", so I assume you don't care about realism.

Deep time gives a /lot/ of room for robofactories to Von Neumann themselves up to at least sextillion-dollars-per-millennia levels, which would have been enough to make the first such station. I'm trying to think of what sorts of evolutionary pressures might have nudged variants of the basic design one way or another, but I'm still hesitant on even just finalizing that initial design, let alone trying to work out how to spread their offspring from one star system to another, let alone working out what resources would most likely be limited enough for those offspring to compete over.

[Anthony]

Originally Posted by DataPacRat

Deep time gives a /lot/ of room for robofactories to Von Neumann themselves up to at least sextillion-dollars-per-millennia levels

Not talking about the economics. It's physically impossible to construct a station like that out of ordinary matter.

[DataPacRat]

Originally Posted by Anthony

Not talking about the economics. It's physically impossible to construct a station like that out of ordinary matter.

What's the physical limit you're thinking of?

I've seen proposals for McKendree cylinders that are 1,000 km in radius (as opposed to this station's 650), which are supposedly the limits for carbon nanotubes; and this station is only rotating fast enough to generate a fifth of a gee, which should offer even more leeway.

(Edit: McKendree's paper can be seen at http://www.zyvex.com/nanotech/nano4/....html#RTFToC17 .)

[Anthony]

Stone armor isn't nanotubes. Aside from that, the big problem is that spaceships uses the wrong scaling law for a lot of things, and when you use the correct scaling law you wind up with something nonsensical.

For example, 1 EP appears to be about 100 W/kg, or 5e+21W in your case. The upper limit of solar panels is about 1 kW/m^2 and realistic value is about a quarter of that, so we need 5e+18m^2 of solar panels, or about a 1.2 million kilometer radius. Radiators have a similar limit.

[DataPacRat]

Originally Posted by Anthony

Stone armor isn't nanotubes.

Stone armor isn't fire extinguishers or airlocks, either; as far as I can tell, Spaceships abstracts away structural supports as just being there anyway.

(Edit: Well, mostly; the current draft spends $300 quintillion on its "spin gravity".)

Aside from that, the big problem is that spaceships uses the wrong scaling law for a lot of things, and when you use the correct scaling law you wind up with something nonsensical.

For example, 1 EP appears to be about 100 W/kg, or 5e+21W in your case. The upper limit of solar panels is about 1 kW/m^2 and realistic value is about a quarter of that, so we need 5e+18m^2 of solar panels, or about a 1.2 million kilometer radius. Radiators have a similar limit.

By EP, I'm guessing you mean a Power Point?

With a bit of GIF-fiddling, the amount of surface-area a Gaea station has to face the sun is about 1.4M km^2. (Including both mirrors to reflect sunlight, and panels to absorb power.) Which is undoubtedly less than your listed numbers.

But since I'm only buying a SM+35 Solar Panel to power the SM+35 Factory to get +1 HP, if that's a problem, I'm willing to nuke both in favour of a couple more Open Spaces, and just have some SM+31-or-smaller panels, factories, and the like.

[Anthony]

Originally Posted by DataPacRat

Stone armor isn't fire extinguishers or airlocks, either; as far as I can tell, Spaceships abstracts away structural supports as just being there anyway.

Spaceships assumes that the armor functions as structural support.

Originally Posted by DataPacRat

But since I'm only buying a SM+35 Solar Panel to power the SM+35 Factory to get +1 HP, if that's a problem, I'm willing to nuke both in favour of a couple more Open Spaces, and just have some SM+31-or-smaller panels, factories, and the like.

Try SM+22 (you have about 1/3,000,000 the area you need). Note that solar panels are in fact cinematic even in the normal size range given in Spaceships.

[ericbsmith]

Originally Posted by Anthony

Spaceships assumes that the armor functions as structural support.

Not really. A ship can be built with as little armor as you want - including no armor at all - and still be assumed to have structural supports. What Spaceships assumes is that each component has enough structural support for itself, and the ship as a whole has enough structural support for all of it's components.

[DataPacRat]

Originally Posted by Anthony

Try SM+22 (you have about 1/3,000,000 the area you need).

Can do. :)

Originally Posted by Agemegos

With 33,000 tones per square metre of load you'd need an 8-km-thick band of nanotube-reinforced polymer, or 1.5-1.7 km of flawless diamond or continuous nanotubes above and below to support the stone.

If it's that important for verisimilitude, then I can always make the 13th system of armor Nanocomposite instead of another Stone. (Looks like it'll add 700k dDR, and $150 quintillion; though I'm slashing the budget by a lot more than that by dropping the SM+35 factory.)

Originally Posted by AlexanderHowl

15 km thick armor seems...excessive for a habitat, as is any production of power points for industrial purposes (just use vast amounts of minifacs). In addition, such a habitat is a massive waste of resources, as you could use the same resources to make 1,000 habitats one-tenth the dimensions each that would have a total surface area ten times as large, allowing them to support ten times as many people. Such a complex of habitats could be connected through static structures that could support solar panels and radiators, and could support any industry that truly needed power points.

And that brings us into the station's actual design goals.

The original builders' purpose was to create what's effectively an offline backup system for their civilization, by placing a selection of stations in various out-of-the-way points in the galaxy; each of which could maintain itself, independently, for x million years, and maintain a population of baseline humans (or near-human equivalent) for the duration. I'm assuming that simply keeping an offline set of records of DNA and some vatfacs prepped doesn't meet their criteria. I'm trying to take some of the lessons of Biosphere 2 into account, and that keeping an active biosphere working for a long time requires more redundancies than is immediately obvious to account for various complex interactions. I'm also assuming that there are issues in most forms of active management of any such collection of ecosystems, so it all has to mostly run itself. (Plus or minus the occasional automated nudge, such as vatfaccing up some individuals of a species that's undergoing too much genetic drift; and with at least one release valve for any human-equivalents who are too curious to avoid poking their fingers into dangerous pies; and with a set of systems to rapidly increase the inhabitants' tech-level if galactic society vanishes for too long.)

Put another way, the purpose of the station isn't maximizing industry, or energy, or even population; it's maximizing absurdly-long-term ecological stability. There are plenty of arguments that could be had about the trade-offs between structural strength and biosphere acreage, but a Varleyian Gaea seems to both be possible without superscience and to provide a plausibly large area, so seems a good starting point.


For example, if I wanted to get a similar amount of acreage with a SM+34 station, I'd need at least 10 of the systems to be Open Spaces (and with fewer armour systems, the radiation protection would be roughly halved); and couldn't do it at all with a SM+33 station, even with all twenty systems being Open Space.

Originally Posted by ericbsmith

Not really. A ship can be built with as little armor as you want - including no armor at all - and still be assumed to have structural supports. What Spaceships assumes is that each component has enough structural support for itself, and the ship as a whole has enough structural support for all of it's components.

:thumbs-up: