Some of the highest priority human health risks regarding the exploration of Mars include carcinogenesis, cardiovascular disease, and immune dysregulation induced by cosmic radiation. These health risks can be mitigated, to some extent, with a properly adapted diet. For this project, we will test the hypothesis that selective breeding of Amaranthus hypochondriacus in simulated Martian regolith previously inoculated with cyanobacteria will result in a viable cold-, drought-, and radiation-resistant nutrient-rich food source; available from both its seeds and leafy biomass. If adapted to extraterrestrial conditions for growth, this plant could serve as a healthy food source during space travel and exploration of the Martian surface. A. hypochondriacus seeds, prior to being planted in simulated Martian regolith, will be challenged with X-rays before germination and in regular times thereafter until leafy biomass and grain have been produced. To assist growth in Martian regolith, we will use nitrogen-fixating cyanobacteria. In regular periods, plant growth and plant nutritional value will be determined by weighing plant mass and measuring nitrogen, carbohydrate, and crude fat content. Nitrogen content will serve as a measure for crude protein content. We expect that A. hypochondriacus plants cultured under these conditions will show increased growth and provide higher nutrient value when irradiated with 250- 2,000 r as compared to unirradiated plants. This project will yield knowledge on the feasibility that nutrient-rich A. hypochondriacus can be adapted to grow in extraterrestrial conditions. Achieving such a food source represents a major milestone in the human exploration of Mars.