Evolutionary and Game Changing Technologies for Solar Power Generation Ted Stern Vanguard Space Technologies, Inc. San Diego, CA

Solar Power Generation Requirements and Approaches Requirements haven’t changed much over the years –Broad power range (Watts – Megawatts) –Launch vehicle compatibility and LV related figures of merit  High mass specific power (W/kg)  High stowed volume specific power (W/m 3 ) –Space vehicle compatibility and SV related figures of merit  High reliability  Operation/survivability in extreme environments (Thermal, Radiation, Plasma)  Structural stability for high power arrays (the reason for high efficiency) –Low life cycle cost - easy qualification and manufacturing –Relevance – Technology development with a clear terrestrial payoff General approaches to address the requirements –Higher efficiency with lower mass / lower volume components –Modularity, standardization, plug-and-play maintainability –More effective shielding with thermal and radiation control

Integrated Manufacturing with Coverglass Replacement Lamination approach for solar panels with continuous front-side shield Integrated manufacturing approach - mechanical and electrical assembly Continuous front surface and intimate flex circuit back-wiring Improved shielding, electromagnetic cleanliness, and solar cell stress control Integral Cover / Shield

Higher Efficiency, Lower Mass, Lower Volume Near-term thrusts –Thin, metamorphic multi-bandgap cells  Modular, compact, low mass  Challenge of a robust panel  Assembly that maintains low mass, low volume  Relevance to solar long duration aircraft and CPV –Solar concentrators – FAST  Modular, compact, shielded  Challenge of optical alignment Game-changing advanced technology –Spectrum converting and Multi-photon enabled photovoltaics  Allows greater spectrum utilization for higher potential efficiencies  Using quantum dot technology  Thermophotovoltaics is another approach – multi-fuel fired? –Advanced coverglass replacement technology with enhanced radiation shielding, charge control, thermal control

Modular Solar Arrays Standardized, modular approach provides multiple benefits –Easier qualification with improved traceability (less scale-up uncertainty) –Easier path to flight for new technology –Cookbook approach to spacecraft design – Projectized  Productionized Responsive build/integration schedules – easy ground maintenance Module options for environmental / threat shielding, electromagnetic cleanliness, advanced cell integration Deployed Wing or Body-Mounted Application

Concentrating Solar Power - Thermal Near-term thrusts –Modular concentrators and optical or thermal transmission bus –Allows independent sizing / optimization –ISRU approach from SBIR for carbothermal oxygen extraction –Thermal furnace or dynamic convertor –Relevance to commercial CSP and military expeditionary power Game changing technologies –Dual-fuel fired dynamic convertors – solar / nuclear –Solar wind turbines

Summary – Getting More From Solar Power Generation Research and Technology Technology investment in advanced materials provides mass, volume, shielding, survivability Better spectrum utilization and conversion efficiency Modularity and standardization provides numerous sizing, reliability, maintainability, and cost benefits Relevance to terrestrial spinoffs is a critical objective