Habitat carrying capacity: how many morphs in a torus?

8 posts / 0 new
Last post
CandyLaser CandyLaser's picture
Habitat carrying capacity: how many morphs in a torus?

I'm running an EP one-shot for my group in the near-ish future. They're aware of the basics of the setting, but haven't dived into the lore. As such, I've decided to adapt Continuity, making some modifications to better fit my group and introduce them to the core concepts of Eclipse Phase. I'm aiming to ramp up the horror element, taking inspiration from Alien, Alien: Isolation, and Dead Space among other things.

The main tweaks are:

1) the station is now a Cognite black lab, and the PCs will be indentures working there. They've received psychosurgery blocking much of their episodic memory (and making things that surprise the players into surprises for the characters as well).
2) I'm going to have the scenario begin with a "day in the life" bit, where the station is functioning normally. A distress call comes in from the Istari, the PCs are sent as the rescue party, they get backed up - then cut to the deactivated station, with the PCs freshly resleeved and exsurgent monsters roaming the hab.
3) the station is significantly larger and has a larger population, allowing me to throw in more jump scares and spooky exsurgent monsters.
4) the habitat is also going to be a torus (or some other hab with spin gravity). This is so I can have normal and microgravity scenes instead of setting the whole thing in microgravity.

It's point 3 that's bugging me. I'd like to get a sense for how many people the habitat can/should support (assuming that most people are in splicer morphs; obviously, the number will be different for habs designed to support only info- and synthmorphs). I want the habitat to have spin gravity comparable to lunar gravity (.16g) or, preferably, Martian gravity (.38g). The habitat can't spin too fast, or that'll make inhabitants sick; the EP books and other research suggests that 2 rotations/minute is the limit there. There's a helpful site that does the relevant math for me, and it says that a torus or cylinder station needs to be about 90m in radius, at a minimum, in order to have .38g gravity and a rotational period of about 30 seconds. If we want it to rotate once a minute, the radius goes up to around 300m.

So, let's say we've got a torus, 90m in radius. Let's also say that the torus is 30m "thick." A little more math tells me that this torus will have a volume of ~1 million m^3. The 300m version will be roughly an order of magnitude bigger in terms of volume. According to NASA a person on a long space mission needs at least 25 m^3 of living space (roughly a 10' x 10' x 10' room). That gives us an upper bound for how many people the torus can support - about 42,000, by volume. Of course, that's not the true figure; it's probably way too high. We need space for mechanical systems, life support, computers, machinery, hydroponics, etc. This is where I'm having trouble. How much space does all of that stuff take up? What's the lower bound for population for a habitat of this size? I could probably tell my players that the station only supports a dozen people and they'd roll with it, but it seems in keeping with the general ethos of EP to have reasonable numbers.

DivineWrath DivineWrath's picture
Unfortunately, such

Unfortunately, such information might be scarce. I don't recall seeing a whole lot. You're best bet is maybe read Sunward and Rimward which is supposed contain information on planets and habs.

Gerlach (Sunward, p. 37) is a good start point. Its an O'Neil cylinder that is 1 km diameter with 4 km length. It has a population of 120000. Its surface area along the length would be 12.5 million m^2, or 105 m^2 per person. It once held 750000 after the fall (overburdened) so it would have about 16 m^2 back then. So maybe use 100 m^2 when things are good and 15 m^2 when its very cramped. These numbers don't take into account multiple story buildings which might increase the area available many fold.

Cythera (Sunward, p. 39) is another example. It is a Torus that holds 50000 researchers. Unfortunately, no stats are given for its size.

It is noteworthy to mention that these are notable and probably larger habitats. Venus is supposed to have 350000 people in orbit, and 28000 are taken up by all the examples Sunward mentions, leaving 70000.

I might do more searching. If I find anything I'll let you know.

CandyLaser CandyLaser's picture
gett

Thanks! I'd combed through the books, but missed Gerlach. Using 100 square meters/person, I end up with about 750 people in the 90m radius torus if the entire inner surface of the torus is used. That won't actually be true - the spin gravity of the torus means that there will be a natural floor and a natural ceiling - but on the other hand, the torus could have multiple decks/internal floors, which would grant extra floor space.

Interestingly, the entry for Gerlach also says: "In addition, the cylinder that makes up the vast majority of Gerlach is connected to a rotating torus that is 1.5 kilometers in diameter and 100 meters wide that rotates to produce full Venusian gravity. This secondary station is primarily a hotel for visitors from low gravity worlds who want to venture down to the surface, capable of accommodating up to 5,000 travelers at a time."

That's a substantially bigger torus than I was considering for my station, supporting far fewer people than I'd expect. Those 5000 guests are going to be served by staff, of course, and they're probably getting more space than necessary - it's about 500 m^2 per person, ignoring staff. Even if there's as many staff as there are guests at any one time, we're still talking about more than twice as much space as the other residents of Gerlach gets.

All of these numbers suggest to me that a population in the hundreds would not be unreasonable for a 90m radius torus.

Baribal Baribal's picture
Future Tech

Taking numbers from NASA is a nice touch, but I'd think that those numbers change with advancing tech. In EP, you don't need hydroponics for food and air, those now come out of nanofabricators, and all that those need is the energy from a probably surprisingly small fusion plant. So even a small statiion should support a large-seeming number of people. However, since your station is a black lab, you have a massive fudge factor that you can use, namely "no user serviceable parts inside" sections. Whether they contain absurdly strongly walled data vaults that are the corp's last, best hope in case of a competitor demolishing their network, or racks and racks of cortical stacks, or the corp's closest approximation of computronium that they can create, or just a whole bunch of fusion plants pumping energy into this box containing that-is-on-a-need-to-know-basis-and-you-do-not-need-to-know, cutting down available space is easy.

Morgan's Butchery | Body bank, morph individualization and upgrades | Psychotherapy and Psychosurgery, therapeutic and recreational | http://eclipsephase.com/comment/59484#comment-59484

nezumi.hebereke nezumi.hebereke's picture
NASA is providing the minimum

NASA is providing the minimum for trained personnel to survive. You may want the minimum you can convince engineers to voluntarily in, which would have a lot more space.

The original cylinder layout, and many books follow this, is approximately one third dedicated living space, one third farming, one third industry (or 'other').

(Edited post, because was dumb)

Shuukyoku Shuukyoku's picture
You probably considered this

You probably considered this but it bears asking; are we talking strictly biomorph? I reckon that many if not most Cognite researchers would exist as infomorphs (depending on the type of research, but it would be cheaper and quicker to do concept work in digital space). If the majority of the station is infomorphs and synths, you could fit a small city in there.

If you took the monsters' point of view, everything they did made perfect sense. The trick was learning to think like a monster.

CandyLaser CandyLaser's picture
Thanks for everyone's help. I

Thanks for everyone's help. I think I can get away with a population of ~500 for the hab, which is big enough to give me what I want without having the hab be so sparsely populated that it strains credibility.

I was thinking about the carrying capacity for biomorphs - you're right that the lab would probably have many more infomorphs and some synths, but for the one-shot I'm going to largely ignore that. I'm trying to introduce the setting to a bunch of new people without overwhelming them; there will be a few infomorphs and synths, but not too many, so that they can be eased into the notion of resleeving and the separation between ego and morph.

DivineWrath DivineWrath's picture
I found this youtube video

I found this youtube video about living in a small house. Its about things you should know before you buy a small house. It shows a 165 square feet house (about 15 square meters), which is not much space to work with.

https://www.youtube.com/watch?v=n7G7p1MPWlM