Humans have a long history of partnerships with a variety of micro organisms. Although the proportions vary widely with individuals, recent scientific estimates suggest that a typical human being has approximately the same number of bacteria and other microbes as they do actual human cells. Now it appears that a partnership with yeast and algae will enable spacefaring humans to use their waste products to produce food and plastics during long duration space flights. Dr. Mark Blenner of Clemson University leads a research group developing strains of yeast which obtain their nitrogen from untreated urine and their carbon dioxide from exhaled breath or the Martian atmosphere which has been converted into yeast food by algae. One of Blenner's yeast strains produces omega-3 fatty acids which are essential for heart, eye, and brain health while another strain of yeast has been engineered to produce polyester polymers which could be used by 3D printers to produce plastic tools and other useful devices. In the future research Blenner's team will focus on increasing the output of these tiny beasts to the point that they will generate useful amounts of nutrients and plastics from astronaut's waste products. This new research when added to the fact that on the International Space Station space travelers now routinely drink recycled water from their urine, sweat, and showers moves us closer to the day when space travelers literally use and reuse every atom that they lift from the Earth's surface enabling journeys that may last for years. The flip side of our partnership with microorganisms is that it is extremely difficult to protect the worlds we explore from a microorganism invasion which would threaten their home grown biology.