Plants In SpaceADDPMP551
The growth of plants in outer space has elicited much scientific interest. In the late 20th and early 21st century, plants were often taken into space in low Earth orbit to be grown in a weightless but pressurized controlled environment, sometimes called space gardens. In the context of human spaceflight, they can be consumed as food and/or provide a refreshing atmosphere. Plants can metabolize carbon dioxide in the air to produce valuable oxygen, and can help control cabin humidity. Growing plants in space may provide a psychological benefit to human spaceflight crews. Usually the plants were part of studies or technical development to further develop space gardens or conduct science experiments. To date plants taken into space have had mostly scientific interest, with only limited contributions to the functionality of the spacecraft, however the Apollo Moon tree project was more or less forestry inspired mission and the trees part of a country’s bicentennial celebration.
The first challenge in growing plants in space is how to get plants to grow without gravity. This runs into difficulties regarding the effects of gravity on root development, providing appropriate types of lighting, and other challenges. In particular, the nutrient supply to root as well as the nutrient biogeochemical cycles, and the microbiological interactions in soil-based substrates are particularly complex, but have been shown to make possible space farming in hypo- and micro-gravity.
NASA plans to grow plants in space to help feed astronauts, and to provide psychological benefits for long-term space flight. In 2017, aboard ISS in one plant growth device, the 5th crop of Chinese cabbage (Brassica rapa) from it included an allotment for crew consumption, while the rest was saved for study. An early discussion of plants in space, were the trees on the brick moon space station, in the 1869 short story “The Brick Moon”.