Well-fed astronauts

Shih-Ger Chang, a senior scientist at the Lawrence Berkeley National Laboratory, has developed a recipe to feed astronauts on a three-year round-trip mission to Mars. His secret ingredient? Human waste. Before you turn the page in disgust, consider Chang’s rationale. “It sounds dirty, but in deep space you can’t afford to throw things away,” he says. “When you burn feces, molecules break down and you get a fertilizer for growing wheat and sweet potatoes.” More specifically, he has discovered that wheatgrass heated to 600