A major challenge facing NASA missions concerns electronics, specifically electrical power and electronic logic, both prompting continual refinement to improve performance. Solar paneling represents a significant fraction of spacecraft weight and bulk. While computer processors and memory continue to improve rapidly, there remain daunting challenges for future missions, especially those requiring a high degree of autonomy. Our effort seeks to capitalize on recent discoveries that suggest a common biomolecular structure, namely the Photosystem I (PSI) protein complex, can be harnessed to provide unprecedented advances in solar power generation and digital logic. The Photosystem I proteins evolved in such a manner as to efficiently transport electrons, induced by sunlight in chlorophyll, across the thylakoid membrane in green plants, creating an electrostatic gradient used by other biological processes. It is reasonable to suppose that such a highly specialized and optimized function might be equally effective in more conventional electronics, and indeed research has revealed a number of startling properties of PSI, specifically its excellent photon conversion efficiency and its semiconductor-like properties. Extrapolation from these early measurements suggests that solar panels constructed from PSI-impregnated substances could outperform current materials by two orders of magnitude in terms of power per weight. Likewise, PSI-derived semiconductor logic may outpace any silicon device in terms of switching speed by as much as three orders of magnitude, and is also expected to function at room-temperature rather than cryogenic temperatures mandated by equivalent conventional devices.
Experiments conducted since 1990 have characterized the coarse behavior of PSI, and other painstaking research begun in the 1980's - culminating in the complete structural mapping of the PSI complex in 2000 - illuminates a number of unusual and surprising features of its internal composition. Our initial research is providing insight into its electrochemical properties in order to bring consistency between the structural and empirical features already discovered. Our second stage of research will conduct a series of experiments designed to first verify this understanding, and then lead to potential dramatic uses of PSI in electronics and nanosystems.
In the third stage of research, we intend to address unique applications of this technology that are particularly beneficial to space missions. These are advanced solar energy collection, self-powered logic, and novel computing architectures. Because a common protein complex is needed for both energy collection and transistor function, the potential exists to seamlessly integrate logic with solar collection, implying a dramatic improvement in computational resources while reducing mass and cabling. Furthermore, by virtue of its dimensions and other properties, PSI may serve as a catalyst for truly revolutionary concepts in computing. As part of this effort we will consider implications of biological self-organization and replication, and explore the potential for self-assembling architectures, new geometries in processor design currently made impossible by silicon manufacturing techniques, and self-repairing computing.