2018 ASHS Annual Conference

Astronaut diets on the International Space Station (ISS) consist of resupplied, packaged food. However, missions to Mars of 3-5 years, will not accommodate re-supply. In addition, many human macro and micro nutrients decrease during long-term storage. Thus, growing plants aboard ISS is essential for providing astronauts with fresh, healthy produce. Thus, NASA is testing an experimental vegetable production unit called VEGGIE to grow fresh salad crops aboard ISS to provide astronauts with healthy diets. VEGGIE is a small plant growth chamber designed as a garden for astronauts that is low in mass and has a low power requirement. Veggie is equipped with light emitting diodes (LEDs) but is exposed to the ISS cabin environment. Plants initially were grown with roots in plastic “pillows” containing baked-ceramic substrate incorporating controlled-release fertilizer and a wick delivering water by capillary action from a reservoir. NASA is testing a next-generation growth unit for VEGGIE called PONDS, consisting of a cylinder with gas-permeable interfaces and capillary-mat slots. The Purdue Mitchell lab in collaboration with NASA is testing growth of salad crops in PONDS within VEGGIE analogs under ISS environments. Specifically, we are evaluating effects of light spectrum and fertilizer treatments on “cut-and-come-again” on productivity and quality of Mizuna. ISS environments being tested include 24/21°C D/N, CO2: 2800 PPM, RH: 45-50% D/N, and photo period: 16hours. Arcillite growing mix with 15 g18-6-8 T 70 fertilizer/liter. LED Light treatments provide total intensity of 330 µmol m^--2s^-1 PAR; with different Red(R): Blue (B): Green (G) ratios. Our treatments are 270R: 30B: 30G, 210R: 90B: 30B, and 150R:150 B: 30G. Plants are grown under those conditions for 8 weeks, and harvested five times at 28, 35, 42, 49, and 56 days. Currently we have our experiment running, and we will have our first harvest in two weeks.