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Old 02-13-2019, 10:57 PM   #6
Rupert
 
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Join Date: Aug 2004
Location: Wellington, NZ
Default Re: [Spaceships] Hydroponics and food vats

I can't recall if I posted this to the forums or not, but here are some workings a bit related to this. It's about making long-occupancy passenger seating rather than renewable food supplies.

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Some thoughts about seats, and life support for small spaceships, using Spaceships:

From Spaceships 7, etc. we know that half the mass of a cabin, etc., or a passenger seat is the life support, and the other half is the fittings (seats, beds, etc.).

A habitat space masses either 8.333 tons or 7.5 tons (I think we can assume that the SM+6 habitat at one space in 5-tons is simply generous rounding, and as flavour text I write cabins in SM+6 ships as being unusually cramped). I'll go with a rounded average of 8.0 tons for cleaner maths.

A passenger seat masses 0.8333 tons or 0.75 tons, or 1/10th as much as a habitat (so about 0.8 tons on average)

So, given that a bunkroom fits four people into one habitat, and half of that is life support, a minimal indefinite recycling system for air and water masses (8.0 / 4) / 2 = 1.0 ton per person.

Also, half a passenger seat is limited life support (24 hours of air and water), and masses 0.8 / 2 = 0.4 tons.

Therefore, if you want a trip that takes longer than 2.5 days, you shouldn't use limited life support. Under that, and you should.

Unfortunately, the rules for No Life Support for seats and cabins do not reduce the price of them, so there's no guidance as to the cost of life support. I'd be inclined to just use the same price per ton for the fittings and the life support, for simplicity.

This makes limited life support mass 0.4 tons per man-day and cost $2,500 per man-day ($6,250/ton). The seat itself costs the same.

Full life support masses 1.0 tons per person, and costs $20K per person (and also $20K per ton). A single bunk costs and masses the same.

This means that a passenger seat, plus fairly spartan full life support, masses 0.4 + 1.0 = 1.4 tons, and costs 2,500 + 20,000 = $22,500, which we may as well just round to 20K to make the table nice and tidy (we'll just assume that the seats are basic, and the mini kitchenette and toilets are *really* basic).

Here's a table of these seats in spaceship systems:
Code:
Long-term Passenger Seating:
SM         +5     +6     +7     +8     +9     +10    +11    +12    +13    +14    +15
Seats       1      3     10     30    100     300     1K     3K    10K    30K    100K
Techs       0      0      0      0      0       1      3     10     30    100    300
Cost ($)   20K    60K   200K   600K    2M      6M     20M    60M   200M   600M    2B
A SM+4 ship will need to use three systems per seat.

We can also say that adding long-term life support to a Control Room costs 20K per station, and requires 1.0 ton of mass, probably in a habitat system (because they're easy to cut up).
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