Out-of-this-world radishes

NASA has reported harvesting its first crop of radishes from plants grown in the Advanced Plant Habitat aboard the International Space Station. Astronaut Kate Rubins picked the 20 radish plants. They were wrapped in foil and placed in cold storage. They will return to Earth in 2021 on SpaceX’s 22nd Commercial Resupply Services mission.

The plant experiment, called Plant Habitat-02 (PH-02), is the first time NASA has grown radishes on the orbiting laboratory in the Advanced Plant Habitat. NASA selected radishes because they reach maturity quickly (in just 27 days) and are well understood by scientists. The plants are also genetically similar to Arabidopsis, a small flowering plant related to cabbage that researchers frequently study in microgravity.

“Radishes are a different kind of crop compared to leafy greens that astronauts previously grew on the space station, or dwarf wheat which was the first crop grown in the APH,” said Nicole Dufour, NASA APH program manager at Kennedy Space Center. “Growing a range of crops helps us determine which plants thrive in microgravity and offer the best variety and nutritional balance for astronauts on long-duration missions.”

Unlike previous NASA experiments that used porous clay material preloaded with a slow-release fertilizer, this trial relies on precisely defined quantities of provided minerals. Red, blue, green and broad-spectrum white LED lights are used to provide a variety of light to stimulate plant growth. Sophisticated control systems deliver water, while control cameras and more than 180 sensors allow researchers at NASA’s Kennedy Space Center to monitor the plant growth as well as regulate moisture levels, temperature and carbon dioxide concentration.

Plan experiments have been conducted with NASA since 1995. Through this research, scientists are able to learn how space conditions like weightlessness affect plant growth and how well the light response and metabolism resembles “Earth-grown” plants. The team has also set up a control population of plants in the ground control plant habitat unit in the International Space Station Environmental Simulator inside Kennedy’s Space Station Processing Facility. Radishes have been growing under nearly identical conditions in the simulator since Nov. 17, and researchers will harvest the control crop Dec. 15 for comparison with the radishes grown on station.