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Old 02-13-2019, 05:57 PM   #1
Agemegos
 
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Default [Spaceships] Hydroponics and food vats

The existing rules in Spaceships offer four ways to supply food, water, and oxygen, and remove carbon dioxide and other wastes.
  1. You can supply each person 4lb of food per day from stores, which are presumably carried as cargo. Water and air are recycled by equipment included in the habitat modules; any supplies it needs are presumably included in the food allowance. 1 compartment of steerage cargo will contain 5 tons, enough for 2,500 person-days.
  2. At TL9 or above you can equip habitat systems with total life support, which halves passenger capacity but provides food. That implies that the food-producing system for a person masses 1.25 tons if the person is in a bunkroom. 2.5 tons if they are sharing a stateroom, 5 tons if they have an unshared stateroom, or ten tons if they occupy a luxury suite.
  3. An open space system dedicated to gardening or hydroponics will supply food and oxygen to an entire ship or habitat. That can work out to as little as 1/8 of a ton of garden per person.
  4. At TL12^ a factory or minifac (replicator) can explicitly create oxygen and food by atomic transmutation. I would have thought the rules implied that a TL11 nanofactory could do so given waste for its raw materials. By the rules for consumables a person's food for the day is $2, and a nanofactory minifac produces $10,000 per hour, so a single nanofactory minifac can feed 120,000 people. (The replicator is far less efficient: a replicator minifac produces 0.05 lb/hr, which is 1.2 pounds per day, enough to feed 0.6 of a person.)
I'm inclined to find none of those rules quite satisfactory. So I'm thinking of combing ballpark figures out of the page on life support at Nyrath's indispensable Atomic Rockets website, and then
  • Specifying a mass for consumables that excludes water (as water is recycled) but includes oxygen.
  • Specifying new Factory systems (and thus, implicitly, minfacs) specialised for the production of food and oxygen. Hydroponics at TL7, algae vats at TL8, vascularised tissue cultures at TL9, etc.
Naturally, I would prefer not to duplicate effort if someone else has already done this. Is anything of the sort available?

Does anyone have any helpful advice or suggestions to offer or make?
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Last edited by Agemegos; 02-14-2019 at 04:13 PM. Reason: Typos
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Old 02-13-2019, 06:05 PM   #2
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Default Re: [Spaceships] Hydroponics and food vats

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Originally Posted by Agemegos View Post
[*] At TL9 or above you can equip habitat systems with total life support, which halves passenger capacity but provides food. That implies that the food-producing system for a person masses 1.25 tons if the person is in a bunkroom. 2.5 tons if they are sharing a stateroom, 5 tons if they have an unshared stateroom, or ten tons if they occupy a luxury suite.
Note that you can also provide no life support and double the capacity. This implies that the basic air and water recycling system masses about 1 ton. A habitat 'slice' weighs 8.333 tons or 7.5 tons, depending on the ship's SM, averaging about 8 tons, so a standard bunk is 2 tons, and as taking out the life support doubles the capacity, that means the life support is half that, or one ton.

I assume that you are using a five-ton slice for a habitat cabin space, based on how much steerage you get for it, but steerage cargo has at least some life support for it.
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Old 02-13-2019, 06:18 PM   #3
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Default Re: [Spaceships] Hydroponics and food vats

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Note that you can also provide no life support and double the capacity. This implies that the basic air and water recycling system masses about 1 ton. A habitat 'slice' weighs 8.333 tons or 7.5 tons, depending on the ship's SM, averaging about 8 tons, so a standard bunk is 2 tons, and as taking out the life support doubles the capacity, that means the life support is half that, or one ton.
Yeah. It also implies that people require twice as much life support if they are in shared staterooms, twice that in unshared staterooms, twice that in luxury suites…. We've pushed Spaceships beyond its intended limits, and it doesn't work well out here.

Quote:
I assume that you are using a five-ton slice for a habitat cabin space, based on how much steerage you get for it, but steerage cargo has at least some life support for it.
Yeah. Based on an 8-ton cabin providing 5 tons of steerage cargo I am reckoning 3 tons for decks, pressurisation, air circulation, and radiation shielding. That gives me 5 tons/cabin for the occupants, partitions, and fittings of the bunks/couchettes/staterooms/suites and a slice of kitchen, dining, washing, toilets, air treatment, and waste treatment.
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Last edited by Agemegos; 02-13-2019 at 06:24 PM.
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Old 02-13-2019, 06:20 PM   #4
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Default Re: [Spaceships] Hydroponics and food vats

While not specifically for spaceships I did some noodling on the topic here
http://forums.sjgames.com/showpost.p...&postcount=182

Some other posts in the thread touch on the subject as well.
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Old 02-13-2019, 06:28 PM   #5
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Default Re: [Spaceships] Hydroponics and food vats

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Originally Posted by (E) View Post
While not specifically for spaceships I did some noodling on the topic here
http://forums.sjgames.com/showpost.p...&postcount=182

Some other posts in the thread touch on the subject as well.
Thanks! That's very helpful.
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Old 02-13-2019, 10:57 PM   #6
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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.

-----------------
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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Old 02-14-2019, 07:03 AM   #7
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Default Re: [Spaceships] Hydroponics and food vats

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Originally Posted by Agemegos View Post
… It also implies that people require twice as much life support if they are in shared staterooms, twice that in unshared staterooms, twice that in luxury suites…
It's not that they require that much mass, it's that they're getting what they paid for. Bunkrooms get air from noisy factory fans, can't set temperature and maybe it varies with other power loads, cheap purification of water and air (strange smells and tastes), 30-second showers, etc. Luxury cabins get scented air, unlimited water, silent responsive climate control, self-cleaning ducts and pipes, etc. Actually, water reserves could be a significant factor in the difference in mass between different cabins (for example, 30 seconds of googling says a filled 8-person jacuzzi weighs 4 tons -- that's a quarter of a luxury cabin's "life support" right there).
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Old 02-14-2019, 11:10 AM   #8
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Default Re: [Spaceships] Hydroponics and food vats

I can tell you from personal experience that quality matters. Enlisted quarters in the USN are bunk rooms while officer rooms are cabins (double occupancy for junior and single for senior). A fleet admiral probably gets the equivalent of a single occupancy luxury cabin (no jacuzzis, but there is plenty of space).

People start to go crazy after six months at sea, which is one the reasons why USN prescription rates for antianxiety and antidepressant drug have skyrocketed, as the USN is extending deployment times to eight months. And you can usually go outside for a break, so the pressures are less than they would be on a comparable spacecraft. Other than the best of the best, like the astronauts that NASA trains, I doubt that many people will be able to tolerate living in a spacecraft bunk room for more than three or four months. Beyond that, it is blood on the bulkheads and brains on the ceiling time, as everyone will try to kill everyone else on board.
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Old 02-14-2019, 11:19 AM   #9
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Default Re: [Spaceships] Hydroponics and food vats

I wonder how USN bunking arrangements compare to those of the early 20th century. At the end of WWI the USN spent quite a bit of time working with the RN, both during and just after the war. The RN was quite impressed with many features of the USN's ships, such as the size of the crew messes and the fittings (collapsible so the mess could be used for many purposes, and of high quality). However, they were quite unimpressed with the USN's sleeping arrangements for their crews, which the RN felt were quite inadequate - so the RN's sailors got better sleep, but worse facilities in other ways.

I wonder if the USN ever successfully addressed this, if they ever considered it a problem.
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Old 02-14-2019, 12:25 PM   #10
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Default Re: [Spaceships] Hydroponics and food vats

I am not sure, but I do know that Australia, Germany, Netherlands, etc. treats their sailors much better than the USA.
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