Hi everyone,

This is an intro about what I plan to build for 1 Meter of Pi Chalenge, and how "Aquaponics Box" will help out the astronauts to eat something fresh.

Challenge

So we have to grow as much food as possible on 1 cubic meter in a corner of a rocket ship.

Main concerns, limitations and possibilities

Biggest limitation is space of 1 square meter, we can't grow much food in that, also no tall plants can grow.

So short plants are preferable, high nutrient values and big yields are a bonus. We can try leafy greens (kale, spinach, lettuce...), and fruity vegetables (beans, peas, beets, cherry tommatoes...).

No offence to vegans but I could not eat only vegetables for the whole journey to Mars (and maybe longer), so some animal proteins and fat would be nice.

Growing cattle or pigs in 1 square meter is simply not possible, but growing fish could be doable, also fish have a byproduct which can be used as nutrients for plants so we don't need fertilizers.

System will depend on the gravity for water flow so it needs to be stationed in the part of the ship that has artificial gravity.

Proposed solution

Aquaponics is an effective way of growing food, the main concept is to feed the fish and fish waste (processed by bacteria) will feed the plants.

• Only input to the system is fish feed, and you can harvest plants and fish for your food.
• You don't need soil for plants (reduces weight), water is used for delivering the nutrients to plants (minimal water consumption).
• Plants don't need to develop big roots to search for food because it is provided to them constantly through water flow, so they can direct their energy to growth of the leafs and fruit.

So we could probably fit all of that in a 1 square meter box, main components would be:

• Fish tank
• Media grow bed (tall plants) + DWC or NFT (leafy greens)
• Sump tank
• Grow area with enough volume to grow vegetables
• Grow lights

• Water pump + tubing
• Air pump + air stones and tubing

• Ventilation and heating
• Controller box and sensors (for controlling the micro climate, and other parameters)

Controller implementation

Raspberry pi will be used for collecting sensor data and controlling micro climate, collecting statistical data and alarming the crew if there are some problems.

Web app will be served over ships WiFi so it can be checked from anywhere inside the ship.

Sensors:

• Enviro HAT: grow space temperature, pressure, humidity, light sensing
• Water temperature sensor
• Water flow sensor
• Water level sensor
• pH sensor (checking water acidity so its good for both fish and plants)
• Camera (monitoring)

Controls with Automation HAT

• Water pump (circulating the water)
• Air pump (for water DO)
• Lights (controlling the day and night cycle)
• Ventilators (bringing the heat down)
• Heater (bringing the heat up)
• Fish feeder

Next step:

Designing the Aquaponic Box, sizing the fish tank, grow bead, sump tank, dwc cannal and grow area so everything fits inside a 1m3 box.

This is a very tricky task and requires a lot of calculation respecting aquaponics best practices so we can get a balanced and stable system.

Until next blog I should have a excel spreadsheet with calculations and a sketchup model of the Aquaponics box.

Aquaponics Box: #2 - Hacking the HATs (both HATs from the challenger kit on single RPi)