Synthetic biology meets bioprinting: enabling technologies for humans on Mars (and Earth)

Abstract

Human exploration off planet is severely limited by the cost of launching materials into space and by re-supply. Thus materials brought from Earth must be light, stable and reliable at destination. Using traditional approaches, a lunar or Mars base would require either transporting a hefty store of metals or heavy manufacturing equipment and construction materials for in situ extraction; both would severely limit any other mission objectives. Long-term human space presence requires periodic replenishment, adding a massive cost overhead. Even robotic missions often sacrifice science goals for heavy radiation and thermal protection. Biology has the potential to solve these problems because life can replicate and repair itself, and perform a wide variety of chemical reactions including making food, fuel and materials. Synthetic biology enhances and expands life's evolved repertoire. Using organisms as feedstock, additive manufacturing through bioprinting will make possible the dream of producing bespoke tools, food, smart fabrics and even replacement organs on demand. This new approach and the resulting novel products will enable human exploration and settlement on Mars, while providing new manufacturing approaches for life on Earth.

Keywords: applied microbiology; biological materials; human exploration; synthetic biology.

Figure 1. The view of Earth from Mars

This view of the twilight sky and Martian horizon taken by NASA's Curiosity Mars rover includes Earth as the brightest point of light in the night sky. Earth is a little left of centre in the image indicated by the arrow, and the moon is just below Earth. The left eye camera of Curiosity's Mast Camera (Mastcam) captured this scene approximately 80 min after sunset on the 529th Martian day, or sol, of the rover's work on Mars (31 January 2014). The image has been processed to remove effects of cosmic rays. The distance from Mars to Earth in this photo was 160×10⁶ km (99 million miles). Image credit: NASA/JPL-Caltech/MSSS/TAMU.

Figure 2. Biological materials that could in principle be produced by microbes off Earth

A diverse range of biological material are produced by multicellular organisms. In some cases, such as with cellulose, there are naturally-occurring microbes that can be harnessed to produce this material on or off Earth. In others, such as spider silk, microbes have been–or will be–engineered to produce these compounds. B. subtilis spore image courtesy of the 2015 Stanford-Brown iGEM team (http://2015.igem.org/Team:Stanford-Brown/BioHYDRA).

Figure 3. Basic food web

The arrows indicate the flow of energy. The source of energy for the majority of life on Earth is the sun [14] Autotrophs such as plants, algae, cyanobacteria and other photosynthetic bacteria use this energy to produce reduced (fixed) carbon compounds from atmospheric or dissolved CO₂ or, in the case of some bacteria, CO. Herbivores, such as the impala shown here, graze on the autotrophs, whereas the carnivores–whether lions, squid or ciliates–are predators who feed on the herbivores. Ultimately organic carbon from these nutritional groups is preserved, degraded by physical and mechanical forces, or metabolized by decomposers such as fungi and many bacteria. Photos taken on the Massai Mara, 7 January 2007.

Figure 4. The grand vision