Bio(synthetic) Engineering is a fundamental approach to engineering based on an important lesson from biology: that the processes used to assemble or synthesize a complex system can make the resulting system more robust, evolvable, adaptive, and richly functional. Therefore, Bio(synthetic) Engineering aims to develop synthesis processes analogous to those occurring in biological growth, neural and cognitive development, and molecular scale self-assembly in living systems. Such developmental processes are also subject to evolutionary optimization. Importantly, however, these synthesis processes are not restricted to biological materials (such as proteins) or to mimicry of biological solutions to engineering problems (biomimetics): Transistors are much faster than nerve synapses, and jet engines are much more powerful than muscles. But the system design principles behind brains and muscles are much more advanced than anything in current engineering practice. These design principles are based on biosynthesis: continuous, molecularly controlled, and evolutionarily optimized processes of growth and development.
Examples of biosynthesis in nature include the construction of wood, teeth, bones, hard shells, spider webs, and many other materials, minerals and mechanical structures. The same is true, on a grander scale, for the construction of nervous systems, brains, and cognition. Morphogenesis--the generation of multicellular form by signaling between cells that can grow, divide, and specialize--couples with molecular assembly at the cellular and subcellular scale to perform fabrication of organic, mineral, and computational structures in an efficient, adaptive and optimizable way from elementary building units. Upon injury, aspects of the developmental self-fabrication process can be restarted to effect repair, resulting in a robust and fault-tolerant system. Evolution takes particular advantage of the developmental process to make large-scale, systematic improvements to a complex system by optimizing its growth rules, in addition to its individual components.
With Bio(synthetic) Engineering, we seek to apply these system design principles to the best available technologies at every level of system organization from devices through distributed intelligence. This novel approach is expected to first become cost-effective for the extremely challenges that arise in space exploration. Table 1 contrasts conventional engineering, biomimetic, and our preferred biosynthetic approaches to engineering autonomous systems at different levels of design from molecular-scale devices to intelligent and distributed systems
Space applications of biosynthetic engineering will be systemic. They will include reduction of launch mass and power requirements for ambitious planetary exploration and space observatory projects. Increased autonomy, smarter spacecraft, and lighter and smarter mechanical, power, and instrument systems will also result. For human spaceflight, intelligent subsystems that support, understand, and cooperate with living systems from plants to astronauts will vastly amplify the capabilities of each human being in space. For robotic mission elements, eventually, launch mass will be nearly eliminated by enabling self-fabrication to proceed in situ on other solid bodies in the solar system.