NASA NTRS · 20205007249
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
Raymond M Wheeler. NASA and Controlled Environment Agriculture (CEA). https://ntrs.nasa.gov/citations/20205007249
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Growing food on extraterrestrial surfaces requires the development of efficient lighting technologies to provide photons for photosynthesis. Here we discuss the development and demonstration of LED panels with a high color fidelity index that can achieve a photon efficacy of 3.6 µmol of photons per joule of input electrical energy. As of June 2021, this is higher than commercial LED fixtures on Earth. This high efficacy makes LED technology a preferred option to solar fiber optics for extraterrestrial applications. Increasing the fraction of red LEDs and photons increases the efficacy but decreases the perception of color.
It may come as a surprise, but NASA has been a long-standing sponsor of controlled environment agriculture (CEA) research. This is based on the potential for using plants (crops) for life support systems in space. Through photosynthesis, crops could produce food and oxygen for humans, while removing CO2. In addition, plant transpiration could help purify waste water. NASAs interest in bioregenerative life support dates back to the late 1950s. At that time, much of the testing focused on algae, but over the years moved toward higher plants as CEA techniques improved. Throughout the 1980s and 90s, extensive testing was carried out at different universities to gather horticultural data for a range of crops, including wheat, soybean, lettuce, potato, sweet potato, cowpea, rice and more. These studies examined different electric light sources, mineral nutrition, recirculating hydroponics, effects of CO2, temperature, photosynthetic photon flux (PPF), and photoperiod on the crops, and identified cultivars that would be useful for space. Findings from these studies were then used to conduct large scale (20 sq m), closed atmosphere tests at Kennedy Space Center, and later at NASA Johnson Space Center, where plant growth chambers were linked to human habitats. Results showed that with high light input and careful horticultural management, about 20-25 sq m of crops under continuous cultivation could produce the O2 for one person, and about 40-50 sq m could produce enough dietary calories. The ability to sustain these production levels and accurately assess system costs and failures needs further study. In all likelihood, the use of plants for life support will evolve, where for early missions like the International Space Station, crops will be grown in small chambers to provide supplemental fresh foods. As mission durations and distances increase, the systems could expand to assume more of the life support burden. But the constraints of space travel require that these approaches be efficient in terms of mass, volume, and energy, which are similar to challenges facing terrestrial CEA, such as vertical agriculture systems.
For over 3 decades, NASA has sponsored research on crops for human life support in space. Specialized watering techniques have even been tested for weightless settings, but most studies used conventional watering, such as hydroponics, which should work well on surface settings of the Moon or Mars. NASAs testing has spanned a wide range of crops and studied innovative techniques to increase yields, reduce power, minimize growing volume, and recycle water and nutrients. These issues closely parallel challenges faced in terrestrial controlled environment agriculture, which is expanding around the world.