Technology demonstrations and flight experiments validating an optical energy infrastructure for Earth-Moon space

摘要

We identify four technical advances that appear necessary to producing an optical power infrastructure in Earth-Moon space as well as specific experiments and demonstrations designed to validate those technical advances. The four advances are: (1) the ability to concentrate sunlight to an integrated power density per unit area that approximates the saturation intensity for a useful laser transition (e.g., 4kW/cm~2 for Nd:YAG) in a volume that matches the lowest order Gaussian mode of free space in a near confocal resonator of practical dimensions (e.g. a resonator a few meters in length) having a cross sectional area adequate to produce substantial coherent output power (e.g., 100kW or more); (2) provide a means of removing waste heat from the laser gain medium in a manner that reduces thermally induced distortion and stress to acceptable levels; (3) identify a specific realizable near confocal resonator of practical dimensions that will selectively and efficiently couple the solar pump power into a lowest order Gaussian mode having the needed cross sectional area; and (4) provide detailed design requirements for a photovoltaic receiver that will transform monochromatic optical power in space into electrical power at efficiencies that approach the theoretical maximum allowed for such devices (e.g. > 90%).