After a terrific series of events at Space, we are all geared up to do more research here to learn about the lifeform that we are going to grow.
Earlier, in 1. SPACE CRASHHH... and need to grow food to survive! Whhat??, we had fully convinced ourselves that we'd harvest Spirulina, so today's research matter would mostly include what kind of environmental conditions are a must for us to maintain healthy growth of these algae systems.
This research is essential to designing a system because we must know beforehand what factors are significant for us to maintain at what tolerances. This ultimately directs us what to monitor and control. This is called a subject matter study in the words of a Design Engineer.
So, lets directly jump over to our research on the design considerations for a Spirulina Farming System:
- Growing Space:
Larger space means generally larger crop yield. So is true for Spirulina. But our constraint is to use 1 cubic meter of space. And I think that kind of space should be enough expecting a high yield of spirulina out of the lesser area.
- Holding Structure:
Holding structure means the container/vessel to be used to contain the water and grow algae in it. This is very important because it should be selected to provide algae with access to a good amount of sunlight. Ideally, we should be able to use some transparent, food-grade material for a holding structure. We will see what we can use or we have available in the next stage of Designing Structures.
- Water:
Spirulina is preferred to grow in alkaline water. We should be able to maintain a pH level between 8-11 to keep the algae edible. Otherwise, the water system might host several other non-preferred lifeforms such as mosquitoes, fungi, etc.
Another very important factor is that the water should be allowed to move, though very slowly at certain intervals to provide equal breathing and growing opportunities for all cells of algae but not hamper their growth by fast movement. Hence we would need to employ some turbines as well at regular intervals of 3-4 hours to stir the water.
Also, the height of the water is important. This is because sunlight penetration is reduced at deeper levels. Therefore, we should just rule out the idea of using opaque containers shaped like a barrel for production because the surface area is important.
- Nutrient Additives (Fertilizers):
Spirulina is dependent on the Water they grow in for all their nutrition capacity. Ideally, the water should be equipped with controlled salts solution at every time.
- Temperature:
Ideally, a temperature level between 30-35 degrees Celcius is preferable for the healthy growth of Spirulina. However, in extreme space conditions, extreme temperature limits are also necessary to be defined between 22-38 degrees Celcius as per studies. Any temperature range beyond the extremes limit will harm adversely to growth and health, maybe leading them to be inedible.
- Sunlight:
The growth rate of spirulina depends on various factors including solar radiation they are exposed to. The amount of light directly affects on photosynthesis process carried out in lifeforms. A close-loop sensor-equipped automated system is required to be integrated to ensure optimum levels of sunlight required for the healthy growth of spirulina.
- Harvesting:
The harvesting process is quite simple. The algae are filtered first using a thin net filter or maybe a porous textile could work followed by a wash in distilled water. And we are good to have fresh Spirulina ready to eat raw. Or we can dry them to store for use beyond 2 days.
Concluding the above points in a nutshell for our design perspective, we will look forward to designing a system which:
Electro-Mechanical Design Requirements:
- Has a large surface area available
- Is transparent to sunlight
- Ensure adequate aeration and water circulation
- Simple harvesting process
Health Monitoring System has to make sure:
- Adequate amounts of light are being received
- Temperature range is maintained all the time
- A regular supply of external nutrition
Aahhh!! That's I believe is good preparation for a healthy life of our to-be grown algae. We have jotted down all the factors *hopefully,* so we don't miss anything later.
The next step, logically also, will be to conceptualize the mechanical design keeping in mind the resources available to us and the constraints of being in space... We should be better working on it! We don't want to die hungry in beautiful space. 
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