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

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/cm2 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., 100 kW 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%>90%).