AI 中文总结
该研究针对拟议的反射轨道太空镜，计算其造成的大气光污染，发现单颗54米直径太空镜会显著改变30公里内夜间环境，400颗同时工作时80公里外可见辉光。
AI 中文摘要
ReflectOrbital计划在约600公里高度的太空发射一面18×18米的镜子，用于照亮地球上半径2.5公里的圆形区域。名为EARENDIL-1的试验卫星是由约50000面更大镜子组成的星座的探路者，每面镜子直径为54×54米，明确目标是为地球提供天基照明。我们计算了在无云条件下，针对不同大气特性和地面反照率，由此类卫星入射光束的瑞利散射和气溶胶散射、以及被照亮区域反射回的光线所导致的天空亮度。我们证明，此类卫星中的一颗造成的光污染非常显著，会改变约30公里范围内的夜间环境。结果显示，在单颗54米直径卫星的光束范围内的观测者看来，该镜子将呈现为视星等-16.7的点状光源，比满月亮约4个星等；漫射天空背景将与日落后不久的黄昏天空相似，亮度高到甚至无法看到最亮的恒星。在14公里距离处，单颗镜子的辉光在大部分天区将超过满月天空的亮度；在34公里距离处，沿光束方向的天空仍会比月光照亮的天空更亮。如果400颗此类镜子同时照亮同一区域，在80公里外就能明显看到其辉光。
英文摘要
ReflectOrbital is planning to launch a $18\times18$\,m mirror in space at a $\sim$600\,km altitude to illuminate a $2.5$\,km radius circular patch on Earth. The pilot satellite, called EARENDIL-1, is a pathfinder for a constellation of $\sim$50,000 larger mirrors, each with $54\times54$\,m in diameter, with the explicit goal to provide space-borne illumination on Earth. We calculate the sky brightness caused by the Rayleigh scattering and aerosol scattering of the incoming beam from one such satellite and by the light reflected back by the illuminated patch, for various atmospheric properties and ground albedos under cloud-free conditions. We demonstrate that the light pollution caused by one of these satellites is very significant, altering the nighttime environment up to distances of $\sim$30\,kms. The results show that for an observer within the beam of a single 54\,m satellite, the mirror will appear as a $-16.7$\,mag point-like source, i.e.~about 4 magnitudes brighter than the full moon. The diffuse sky background will be similar to the dusk sky shortly after sunset; too bright to see even the brightest stars. From a distance of 14\,km, the glow from a single mirror will exceed the luminance of the full moon sky for majority of the sky. From a distance of 34\,km the sky will still appear brighter than the moon-lit sky in the direction of the beam. If 400 such mirrors illuminate the same patch simultaneously, the glow will be obvious from 80\,kms.
CommentsAccepted for publication in ApJL. Visual renderings at https://starryprinceton.org/scattering_calculations_renderings
