Continually supplying a crew with food becomes an impossible task as a mission’s distance from Earth increases. If NASA is to conduct long-term manned missions and eventually attempt colonization of the moon and planets, they need to be able to grow their own food.
This requires a regenerative and compact system which uses as little resources as possible to control the factors involved in plant production: light, temperature, carbon dioxide, and nutrients. NASA’s Veg-01 experiment is turning to hydroponics as a solution to feeding crews on long-term deep space missions and, eventually, the inhabitants of torus stations and other planetary dwellings (most likely Mars).
For sanitation and space-saving purposes, these modules won’t have media beds or NFT gutters. They’ll be equipped with “plant pillows” that are injected with nutrient solutions. The plant pillows contain calcined clay and a sterile growth media containing granulated controlled release fertilizer.
Although the astronauts have tasted some of their lettuce, it has yet to be approved as safely edible. The ISS crew has instead sealed and frozen the plants for return to Earth. Once the safety protocols are settled, they will be able to enjoy their harvest as well as the free, naturally produced oxygen they have already been enjoying.