NASA's Advanced Life Support Breadboard Project at Kennedy Space Center focuses on biological regeneration of essential commodities for long-term space missions. If plants are grown on these missions, roughly 50% of the biomass will be inedible. Composting can reduce the volume of inedible biomass, reduce levels of leachable soluble organics, and produce a mineral-rich leachate that can be used to provide nutrients to subsequent generations of plants. Other wastes will also be generated on space missions; co-composting of these wastes should increase the rate and extent of degradation and should assist in control of moisture content during composting. To investigate these assumptions, we added simulated human solid waste to freshly harvested inedible wheat biomass and composted the mixture for 21 days.