28 kilograms of oyster mushrooms can be grown on it in two months
Which mushrooms are best on the Moon? How many can be grown to feed a group of astronauts? Specialists of the Siberian Federal University (SFU), together with colleagues from the Institute of Biophysics of the Siberian Branch of the Russian Academy of Sciences, thought about this and developed a project for a lunar farm on which it is possible to effectively cultivate oyster mushrooms. They reported this in Helion magazine.
Mushrooms have long been considered by nutritionists as the ideal diet for travelers to other planets. Unlike plant food, in addition to protein, they contain valuable vitamin D, and therefore, if it is impossible to obtain animal food, they can become its only source in the bioregenerative life support system of the space station. Eating mushrooms will help neutralize the effects of free radicals. In addition, they are very easy to grow, because straw left over from growing space wheat can be used as a substrate for them, and the spent substrate after growing mushrooms can, in turn, also serve as fertilizer for growing other plants. You will get a real waste-free production.
Among the various types of cultivated mushrooms, the researchers' choice fell on oyster mushrooms, which are very low in saturated fat and cholesterol. But at the same time they are a good source of protein, thiamine, vitamin B6, folic acid, iron and magnesium.
The next step for scientists was the concept of a mushroom farm. In their opinion, it should consist of two connected modules. Each module is a double-walled rigid aluminum tube-in-pipe structure 17 meters long and 6 meters in diameter. Double walls are needed to protect against radiation. The first module is used to prepare and sterilize the substrate, while the second module is used for sowing and growing mushrooms.
However, while oyster mushrooms have grown in scientists in a conventional laboratory. According to the developers of the concept, before creating a farm «in iron», they needed to conduct an experiment on growing oyster mushrooms on straw and understand what the vessels for growing should be, what should be the density of the substrate, how many «mushroom bodies» could eventually be collected. Scientists worked in a clean room simulating a lunar farm, preparing the substrate, sowing mushrooms, harvesting, disposing of the spent substrate and cleaning the module.
As a result, having tried to grow mushrooms in different modes, they came to the conclusion that the best substrate density for «moon» oyster mushrooms is 500 or a little more grams of processed straw per liter, and the volume of the growing container is 1.5 liters.
With these parameters, in one technological cycle lasting 66 days, 28 kilograms of mushrooms can be grown on the farm. According to the calculation of American nutritionists, referred to in the article by Russian scientists, each crew member could consume more than 30 grams of fresh fruiting bodies per day — dietary restrictions that prevent increased consumption of oyster mushrooms are unknown. But if at some point the cosmonauts got tired of them, they could be harvested for future use during overproduction.
Now Siberian scientists will wait for the launch of the manned lunar program, which is planned after 2030. Until that time, they hope to prepare their mushroom farm for flight, having previously tested it in space. Perhaps its prototype will still have time to fly to the ISS.