Researchers at the University of Arizona have developed a greenhouse that grows plants without soil. The prototype greenhouse is an 18-foot long tube that contains water-cooled sodium vapor lamps and “envelopes” to hold the seeds.

It’s dubbed the lunar greenhouse. The idea is that something similar could one day supply food to astronauts on the moon or Mars. It would be buried beneath the moon’s surface, so to not be destroyed by cosmic rays and solar flares, and would be operated autonomously, so that food could be ready when astronauts arrive. A lunar greenhouse could be essential for colonizing the moon, which has no atmosphere, no natural water, and extreme temperatures.

The Arizona system works by feeding carbon dioxide into the greenhouse through pressurized tanks. At a lunar base astronauts would provide carbon dioxide by breathing, and water for the plants could be extracted from their urine. Sunlight could be channeled to the underground plants through fiber optic cables.

According to the Arizona researchers, led by Gene Giacomelli, the system contains about 100 kilograms of wet plant material that can provide 53 quarts of drinkable water and a small amount of oxygen during a 24-hour period, while consuming about 100 kilowatts of electricity and half a kilogram of carbon dioxide. It can even be collapsed into a four-foot wide disk for interplanetary travel and deployed in less than ten minutes.