The development and operation of a Satellite Power System would place very large structures in orbit around earth for several decades. Sunlight reflected off such structures, particularly specular components from large flat areas, would be expected to create ground illumination. This report deals with the potential effects of reflected light on human and animal eyes in daytime and the potential impacts on circadian rhythms, plus migration and navigation effects on nocturnal animals including open ocean marine animals and birds. For plants, the available evidence indicates that ground irradiance from SPS will not affect the growth or development, and although plants are sensitive to low intensity radiation, the duration of the irradiation provided by reflection from SPS are insufficient to cause developmental changes.