The support system will introduce the carbon dioxide astronauts exhale into the greenhouse and will release the oxygen plants produce into the human settlement. It will pump oxygenated water with the appropriate nutrients across the plants' root zone, collecting and storing what's left at the end. The idea is to use water humans bring from Earth. However, if they're staying on the moon or on Mars forever, NASA has to find a water source in their new homes.

While plants here at home grow under the sun, the greenhouse will likely have to be buried underground to protect the plants from radiation. Early Martian or moon settlers can either use LED lights or capture solar light and beam it underground using fiber optic bundles. Both kinds successfully grew plants during the researchers' test in an 18-x-8-foot prototype,

Eventually, the team could create greenhouses in various sizes for different plants, depending on what they decide astronauts should bring. For now, they're planning to develop computer models to simulate future tests and to control the environment inside the greenhouses.