Evolutionary and Game Changing Technologies for Solar Power Generation

1. Evolutionary and Game Changing Technologies for Solar Power Generation Ted Stern Vanguard Space Technologies, Inc. San Diego, CA tstern@vst-inc.com

2. 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/m3) • 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

3. 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

4. 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

5. 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

6. 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

7. 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