[GURPS Spaceships] TL9 SM+15 Space Habitat

[Peter Knutsen]

This is an attempt to make a huge space habitat. The shape should be some kind of elongated cylinder, so I figure 60% of the SM's default length would be good. That's 420 yards in length, or about 375 meters. Since I don't know what the volume is, I can't calculate the diameter, but obviously it would be in the order of magnitude of some hundreds of meters.


Size: SM+15
Hull type: Un-streamlined, long cylinder
TL: 9

Front

[1] Factory. The station has to be able to produce stuff for the needs of the inhabitants. Since they mostly have what they need already, the factory usually runs at 10% capacity. Can make stuff worth 150 million dollars per hour at full capacity, 300 workspaces, cost 150G$ (is this a typo? It's very expensive).

[2] Normal cargo space, to store the raw materials needed for the Factory, or the unprocessed materials needed by the "mining" unit. No cost. I'll arbitrarity assign 6 workspace, for people to keep track of supplies, but the actual moving of stuff out of the cargo space is done by factory workers or mining workers. No cost, but 6 workspaces. 150k tonnes capacity.

[3] Split module:
2/3 Mining Materials Processing, to process imported minerals (usually mined from asteroids and sold to the habitat), 10k tonnes per hour of mineral processing capacity (can fill the cargo space in 15 hours, but is normally run at low capacity, e.g. 10%).
1/3 Fuel Refining, to produce fuel for auxillary craft (in the Hangar Bay module), can process 15k tonnes of fuel per hour if running at full capacity (but usually it runs at much less).
Total cost 3G$, 300 workspaces.

[4] Hangar Bay, 100k tonnes capacity, launch rate 5000 tonnes per minute (takes 20 minutes to launch or dock full capacity), 300 workspaces, 300M$

The design complement for this type of habitat is two large SM+10 ships (20k tonnes), 60 medium-sized SM+8 ships (60k tonnes) and 200 small SM+6 ships (20k tonnes). Most ships will be for transport of cargo (the two large ones, and roughly 3/4 of the medium ones and 1/4 of the small ones) or passengers. The cost of auxillary craft is not included in the cost of this habitat.

[5] Fuel tank, to store reaction mass for the Hangar Bay's ships, or the unprocessed fuel raw materials (hydrogen, probably). 150k tonnes capacity, cost 1$B. Un-manned, since the Hangar Bay crew takes care of refuelling the smallcraft, and the refinery crew handles pumping material from here and to the refinery.

[6] Weapons, tertiary battery (normally 30 weapons), 3 actual weapons, with the remaining 90% devoted to refridgerated cargo storage.
Weapons: 3 lasers with the VRF option (since they are intended to be used for meteorite defence only). Cost 1.5G$, 30 workspaces.
Cargo space, refridgerated: 135k tonnes, cost 68M$. The PDF assigns no workspaces to refridgerated cargo space, but since this is such a large facility, I'll arbitrarily assign 30 for maintenance.

Mid
[c] Control Room. Since the habitat has no proper engines, the Control Room's very low-powered thrusters must be used to shift orbit, which happens very, very slowly (the captain may need to plan decades ahead). Also, most of the computing powers fill the needs of the station's inhabitants, and most of the Control Room's control stations are manned by people who supervise the internal functioning of the space station, including senior law enforcement and administrators (the regular cops and administrators have habitat offices of their own). Computer complexity 9, comm/sensor grade 13 (TL+4), 60 control stations, 300 workspaces, cost 6G$.
edit: Like the core module in the Rear section, this module, the Control Room, is in zero gravity.

[1-6] 6 Habitat modules, totalling 120k "cabin units", 1800 workspaces, 18G$.

Rear
[c] Open space, devoted to zero-gravity recreation (small shag-cabins intended for 2-6 temporary ocupants, larger orgy rooms, zero-gravity ballgame areanas, zero-gravity water tanks), cost 60M$ (tripled because of the need for improved containment of the water, and various systems to remove bodily fluids and skin particles from the air), 60 workspaces (tripled; the extra workers are paramedics standing by in case of emergencies, or someone demanding an immediate STD test).

[1] Open space, devoted to food production sufficient to feed the entire habitat and even produce a little excess food which is stored in the refridgerated cargo space (mentioned above). Once the emergency store is full, any excess food is exported to other stations or even to the Lunar or Martian colonits. 300 workers, cost 20M$.

[2-4] Open space, devoted to parkland, soccer fields, fishing ponds, light forest, and so forth. 600 areas (30 acres, or 12 hectares, which is 400 by 600 meters), 900 maintenance workers (techs), cost 60M$.

[5] Overall Steel Armour, covering the entire ship with 1/3 of the SM's dDR, which gives a dDR of 23, or a DR of 230. IIRC in GURPS, DR 70 is the same as 25 mm of steel, so we're talking over 75 mm of steel here, which should give quite good protection against radiation, and even tiny meteorites. Cost 600M$.

[6] Power Plant (Fusion). Plenty of energy is needed to support the luxurous lifestyle of the late 21st century (even if a little of the power is occasionally used to power the meteorite defence system), and the 1 Power Point provided by this de-rated system provides plenty of fun (doubled endurance to 100 years). 300 workspaces, cost 30G$.

Design options:

Spin gravity. The maximum gravity, at the outer edge of the habitat, just next to the steel armour, is 1.15G but cabins and parkspace are distributed inwards so that one can choose to live and recreate in any gravity from 1.15G (mostly popular with sports types, paramilitary types and actual military or law enforcement, who want to stay in very good shape) and down to near-lunar gravity (0.20G), although with most living and recreational space clustered around Earth gravity and Martian gravity. Cost 300M$, no maintenance crew needed (people's conflicting desires for living quarters in specific gravity bands are handled by the Control Room).

"Cabin unit" breakdown (120k cabin units total):

1200 bed hospital (1200), gives a +4 bonus to relevant medical skill rolls (as per "Hospital Bonus", p18, and assuming that TL9 divided by 2 is rounded down)

350 large establishments (7000, x5 normal size), each accomodates 100 patrons, for a total of 35k patrons (a few of these are combined into super-sized establishments).

3500 establishments (7000), each accomodates 10 patrons, for a total of 35k patrons (a few of these are probably combined into double- or triple-sized establishments).

700 office law enforcement unit (700).

300 office administrative unit (300).

25k double-size luxury cabins (100k), half expected to contain 1 person, the other half 2 persons (some of these are combined into larger luxury suites, or to family units to accomodate larger numbers of people who wish to share a home), for a total population of 37.5k people.

3800 unused "cabin units" (can be used for normal cabins for the crew. At 2 people per cabin, that's 7600 crew, which is more than enough, since the requirements total up to only slightly more than 4500).




Total number of workers needed to man modules: 4686
(60 to man the control room, the others to perform more or less manual work, and with habitat staff (medical, law enforcement, administration) not included (these total 700 law enforcement, 300 administrative, and sufficient nurses, med technicians, physicians and surgeons to man a 1200 bed hospital).

Total cost of habitat: 210.6 billion dollars
(Cost per inhabitant, assuming 37.5k inhabitants: 5.6 M$)
(Also note that almost 3/4 of this cost is the Factory module)

I don't have an easy way to calculate the cost of the auxrillary craft, but they total to a mass of 100k tonnes, so it would be fairly expensive if viewed in isolation, although probably near-trivial when compared to the 210 billion dollars cost of the habitat itself.


Edit: Specifying that the [core] module Control Room is in zero gravity.