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.