自1923年赫尔曼·奥伯特提出“按需阳光”概念及1993年俄罗斯“旗帜-2号”（Znamya-2）展开20米反光镜在地面投射5公里光斑以来，太空反射太阳能技术一直备受瞩目。成立于2021年并已筹集逾2,800万美元资金的加州初创公司Reflect Orbital正试图将其商业化，计划于今年晚些时候发射测试卫星“埃兰迪尔-1号”（Eärendil-1）。该卫星将在625公里的轨道高度展开面积达160平方米（相当于排球场大小）的超薄镀铝薄膜镜面，向地球表面投射直径约5.5公里的光斑。

根据该公司测算，只需在特定极地轨道部署76颗卫星，即可在地球任意角落按需提供满月亮度的光照；其长远规划则是部署数万颗更大的反光卫星并叠加光束，每枚SpaceX的猎鹰9号火箭可搭载约120颗此类卫星。该项目的核心商业逻辑在于傍晚与清晨电力需求旺盛且电价高昂的时段，将阳光聚焦照射至地面光伏电站以提升发电量，进而减少电网对高昂储能电池的依赖；此外，该技术还可服务于应急救援、夜间采矿作业乃至替代城市路灯以由数百万居民分摊成本。

格拉斯哥大学2022年的一项研究表明，若火箭发射成本下降至当前水平的三分之一（如SpaceX星舰投入使用），太空反射镜阵列在经济上完全具备可行性。然而，光污染问题引发了天文学界的强烈担忧：斯洛伐克科学院8月6日发表的一篇预印本论文估算，在Reflect单颗大型卫星光束照射范围内将无法肉眼观测到任何恒星；若400颗卫星联合聚焦以达到光伏发电所需的最低照度，其产生的光晕在80公里外仍清晰可见。尽管公司承诺通过偏转卫星角度设立天文台避让禁区，但潜在的严苛监管仍是其生死存亡的关键考验。

Space-based solar illumination—conceived by Hermann Oberth in 1923 and tested in 1993 by Russia’s Znamya-2 satellite, which unfurled a 20-metre mirror reflecting a 5km beam—is approaching modern commercial reality. California startup Reflect Orbital, which has raised over $28m since 2021, plans to launch its demonstrator satellite, Eärendil-1, later this year. Operating at an altitude of 625km, the spacecraft will deploy booms supporting a 160-square-metre aluminium-coated mirror—comparable to a volleyball court—to direct a 5.5km footprint of reflected sunlight onto Earth’s surface.

The startup calculates that a minimal constellation of 76 satellites in tailored polar orbits could deliver full-moon brightness on demand anywhere on Earth. Ultimately, it envisions tens of thousands of larger satellites deployed in batches of roughly 120 per SpaceX Falcon 9 launch, combining their beams over target regions. By focusing supplementary irradiance onto terrestrial solar farms during dawn and dusk peaks when grid prices are highest and generation drops, the system aims to complement and downsize costly battery backup requirements, while additionally servicing disaster response, overnight mining operations, and municipal street lighting.

Academic assessments, including a 2022 University of Glasgow study, indicate such constellations become economically viable if launch costs drop to a third of current levels—a threshold brought closer by SpaceX’s Starship. Nonetheless, severe astronomical disruptions loom. An August 6th study by the Slovak Academy of Sciences calculated that ground-level observers within a satellite’s beam would see no stars, and that the minimum 400-satellite cluster required for solar power generation would produce skyglow visible 80km away. Although the company pledges telescope exclusion zones, mounting light-pollution backlash threatens strict regulatory intervention.

Source: Space-going mirrors could offer daylight on demand

Subtitle: Applications stretch from disaster relief to street lighting

Dateline: Sep 24th 2026\n