Years ago, I reverse engineered the Hydroponics Domes on the Invader class Jumpship (along with a lot of research into modern hydroponics systems and theoretical systems envisioned by NASA) to yield the following:
Hydroponics Dome: Optional Aerotech equipment
Hydroponics Domes are automated food factories that can provide fresh fruit, vegetables, and grains as well as acting as a natural air and water filtration system in lieu of artificial systems. A Hydroponics Dome measures 100 meters in diameter and reaches a height of 24 meters at the top of the Dome from the base. Divided into three seven-meter decks, this provides enough space for a full 1,250 kg of food output every day with year-round sequencing of harvest. Automated tending systems harvest the output of a portion of the Dome every day that permits a continual supply of food for up to 325 people. The major limitation of the system is the fact that it provides little to no high-protein foods that make up 20% of an average diet. As such the Hydroponics Dome can only extend normal food reserves, not replace them entirely.
Wastewater from the Jumpship crew and any attached Dropships is cycled into the Hydroponics systems for a two-fold benefit. First, it provides a natural system of water filtration, allowing tons of artificial filtration systems to be removed. Secondly it provides most of the nutrients necessary for healthy plant growth. Artificial air filtration and recycling systems can also be removed as the Domes replace their function as well. With a steady supply of meat and dairy products for the crew and passengers (necessary anyway for the health of the crew) it adds lost nutrients into the system, keeping the system viable without extensive 'support' animals normally necessary for healthy plant growth.
Game Rules:
Hydroponics Domes weigh 150 tons and cost 5 million C-Bills. Each Dome will extend the man-day value of food stores from 200 man-days per ton to 1,000 man-days per ton for a maximum of 325 people per Dome. This is usually sufficient for a Battalion-sized unit. Optionally, Invader class Jumpships may automatically have two of these Domes, consuming 300 tons of cargo space. (this also eliminates the price discrepancy of 13 million C-Bills for building an Invader using the construction rules of 487 million C-Bills vs. the canon 500 million C-Bill price)
Manually operated Domes only have a cost of 1 million, but require a crew to tend the plants and harvest them. Output of manual Domes is only sufficient for 20 people per day per crewman tending the Dome, up to the maximum of 325 people per day. (thus a manually operated Dome requires 17 personnel to fully exploit the output)
The weight is only the added equipment necessary to run the automation or provide the tools necessary to tend the Domes manually. The remainder of the weight comes from reduced Life Support equipment needed to recycle the air and water of the ship's crew and the ship's structure itself. A typical Invader class Jumpship can extend the food supplies of most of a Regiment of troops, or provide a steady income if the food supplies are sold commercially. If commercial sale is opted for, every ton of output will provide 100 C-bills of income. (commercial sale income includes the need to buy nutrients and water lost from waste reclamation)
Also, here's a fairly workable set of guidelines for creating custom Hydroponics using the same information.
Mass = 20 tons + 0.4 tons per person per day; add 30 tons + an additional 0.4 tons per person for complete diet (50 tons + 0.8/person)
Area = 39 m² per person + 62 m² per person for complete diet (7 meter height assumed for volume)
Cost = 880,000 + ( Area/person x People² ) rounded up to the next 1,000; + 1 C-bill per person per day for complete diet replacement nutrients
Thus, a 5-man complete diet Hydroponics bay weighs 54 tons, takes up 505m² of area, (3,535m³) and costs 893,000 + 5 C-Bills per day to maintain it. With these values, the canon Hydroponics bays on the Invader are the break-point of cost vs. mass. Increase to a larger size and cost starts getting really high. Decrease it much below them and the weight savings isn't realized due to the 20-ton minimum weight. (this is the bare minimum for enough water to work hydroponics at all... water is heavy )
Anyway, I like it! (but then, I made it )
YMMV as always. 8)
