This company’s plans to deploy space mirrors could jeopardize the night sky for many
This company’s plans to deploy space mirrors could jeopardize the night sky for many
这家公司部署太空镜的计划可能会危及许多人的夜空
EXECUTIVE SUMMARY A company that plans to beam sunlight from space to Earth on demand might unintentionally brighten the night sky for many more people than intended, according to a new study. 执行摘要 一项新的研究显示，一家计划按需将阳光从太空反射到地球的公司，可能会在无意中让比预期多得多的人面临夜空变亮的问题。
Later this year, the US company Reflect Orbital plans to launch a test satellite called Eärendil-1 that will extend an 18-by-18-meter mirror in orbit. The goal is to test the feasibility of the company’s plans to launch up to 50,000 larger satellites, measuring 54 by 54 meters, and reflect sunlight to Earth on demand. 今年晚些时候，美国 Reflect Orbital 公司计划发射一颗名为 Eärendil-1 的测试卫星，该卫星将在轨道上展开一面 18x18 米的反射镜。其目标是测试该公司计划发射多达 5 万颗更大的卫星（尺寸为 54x54 米）并按需向地球反射阳光的可行性。
The case for doing this remains somewhat uncertain, but Reflect Orbital has said the goal is to prolong the hours of sunlight for various uses, including solar panel charging, emergency response, and military activities. The launch, which was approved by the Federal Communications Commission in July, has been met with disbelief by astronomers and environmental groups. 虽然这样做的必要性尚不明确，但 Reflect Orbital 表示，其目标是延长日照时间以用于各种用途，包括太阳能电池板充电、应急响应和军事活动。此次发射已于 7 月获得美国联邦通信委员会（FCC）批准，但遭到了天文学家和环保组织的质疑。
“This is incompatible with astronomy,” says Samantha Lawler, an astronomer at the University of Regina in Canada. “There is no way you can do this and preserve dark skies.” “这与天文学是不相容的，”加拿大里贾纳大学的天文学家萨曼莎·劳勒（Samantha Lawler）说，“你不可能在这样做的情况下还能保护黑暗的夜空。”
Miroslav Kocifaj, an astronomer at the Slovak Academy of Sciences, and his colleagues have now calculated the broader effect on the night sky. In a new paper published online and accepted for publication in the space journal Astrophysical Journal Letters, they studied the extent to which the light the satellites beamed to the ground would scatter. 斯洛伐克科学院的天文学家米罗斯拉夫·科西法伊（Miroslav Kocifaj）及其同事现已计算出这对夜空产生的更广泛影响。在一篇已在线发表并被太空期刊《天体物理学杂志通讯》（Astrophysical Journal Letters）接收的论文中，他们研究了卫星向地面反射的光线会散射到何种程度。
They found that within the beam’s target area, intended to be a circular patch five kilometers across, a single Reflect Orbital satellite would appear about 40 times brighter than the full moon in the sky. As far as 14 kilometers away from the center of the beam, the satellite would still be as bright as the full moon. 他们发现，在光束的目标区域（预定为直径 5 公里的圆形区域）内，单颗 Reflect Orbital 卫星的亮度将比天空中的满月亮约 40 倍。即使在距离光束中心 14 公里远的地方，该卫星的亮度仍相当于满月。
Combining the beams of 400 satellites, which Reflect Orbital eventually plans to do, would yield a light as bright as 10,000 full moons within the five-kilometer area, or 2.4% as bright as the sun. Even up to 80 kilometers away, Kocifaj and his colleagues calculated, this combined beam would be visible as “a glow above the horizon,” he says. Reflect Orbital 最终计划结合 400 颗卫星的光束，这将使 5 公里范围内的光线亮度达到 1 万个满月，或相当于太阳亮度的 2.4%。科西法伊及其同事计算得出，即使在 80 公里外，这种组合光束仍可见为“地平线上的一道光芒”。
That means the night sky would be altered for many more people than those within the area Reflect Orbital intends to illuminate. “Deploying these mirrors would be seriously damaging for astronomy and for the nighttime environment,” says Kocifaj. “The damage extends far beyond the target area.” 这意味着，受夜空改变影响的人群将远超 Reflect Orbital 计划照明区域内的人数。“部署这些反射镜将对天文学和夜间环境造成严重破坏，”科西法伊说，“这种损害远远超出了目标区域。”
Olivier Hainaut, an astronomer at the European Southern Observatory in Germany, says the results of the paper are not surprising but are still useful. “These guys are really good at that kind of modeling,” he says. “They know what they’re doing.” 德国欧洲南方天文台的天文学家奥利维尔·海诺特（Olivier Hainaut）表示，该论文的结果并不令人意外，但仍然很有价值。“这些人非常擅长这种建模，”他说，“他们知道自己在做什么。”
Hainaut had previously modeled the broader effect of Reflect Orbital’s beams, finding they would brighten the sky up to 300% worldwide. This latest work gives an even more complete picture of what the impact would be. “These two papers really cover most of it,” he says. 海诺特此前曾对 Reflect Orbital 光束的更广泛影响进行过建模，发现它们会将全球天空亮度提高多达 300%。这项最新研究提供了更完整的潜在影响图景。“这两篇论文确实涵盖了大部分内容，”他说。
Reflect Orbital CEO Ben Nowack disagrees with the findings of Kocifaj’s paper. “Some assumptions are simply inaccurate,” he says. “The critical point is that our safeguards, including maintaining exclusion zones, take account of scattering.” Reflect Orbital 首席执行官本·诺瓦克（Ben Nowack）不同意科西法伊论文的结论。“一些假设是不准确的，”他说，“关键点在于我们的保障措施（包括维持禁区）已经考虑到了散射问题。”
He says that the company has “engaged substantively with legitimate concerns raised by astronomers, environmental researchers, and scientists,” and that their feedback has “informed our technology and operational plans.” 他表示，公司已经“实质性地回应了天文学家、环境研究人员和科学家提出的合理关切”，并且他们的反馈“为我们的技术和运营计划提供了参考”。
Kocifaj says that Reflect Orbital has not provided data to back up its claims. The company “states that safeguards exist, that scattering is taken into account, and that the models are being updated, but it gives no numbers, no description of the model, no assumptions, and no data,” he says. “There is therefore nothing that can be engaged with technically. Our calculations produce concrete figures.” 科西法伊表示，Reflect Orbital 并未提供数据来支持其说法。他说，该公司“声称存在保障措施、考虑到了散射、模型正在更新，但没有给出任何数字、模型描述、假设或数据。因此，在技术层面上没有任何可供讨论的内容。而我们的计算得出了具体的数字。”
Reflect Orbital’s intention is to place its satellites into highly inclined orbits above Earth, almost from pole to pole. This will enable them to reflect sunlight in the hours before sunrise and after sunset, extending daylight hours in certain locations. Eventually, the company has said, it wants to place satellites high enough to provide light 24-7 to locations on Earth. Reflect Orbital 的意图是将卫星置于地球上方的高倾角轨道上，几乎覆盖两极。这将使它们能够在日出前和日落后的时段反射阳光，从而延长特定地点的日照时间。该公司表示，最终希望将卫星放置在足够高的高度，为地球上的地点提供 24/7 的照明。
In August, a group of organisations including DarkSky International and the American Bird Conservancy urged the FCC to review its approval of the Eärendil-1 satellite. As well as the impact on astronomy raised by this and future satellites, the group also highlighted potential negative consequences for aviation and wildlife. 8 月，包括国际暗夜协会（DarkSky International）和美国鸟类保护协会（American Bird Conservancy）在内的一组组织敦促 FCC 重新审查其对 Eärendil-1 卫星的批准。除了该卫星及未来卫星对天文学的影响外，该组织还强调了对航空和野生动物的潜在负面后果。
“Our primary request is straightforward: Reverse the Space Bureau’s order, and require a lawful public-interest and NEPA [National Environmental Policy Act] review,” the group said in a statement. “我们的主要诉求很简单：撤销空间局的命令，并要求进行合法的公共利益审查和《国家环境政策法》（NEPA）审查，”该组织在一份声明中表示。
The satellites could also pose risks to humans, according to Reflect Orbital itself. In a filing with the FCC in March, the company said that observing Eärendil-1 with a telescope larger than 12 inches —which many astronomers have access to—may be unsafe for human eyes. It added, though, that such observations are “unlikely to … result in significant injury” because the satellites are not constantly bright. 据 Reflect Orbital 公司自己承认，这些卫星也可能对人类构成风险。在 3 月份提交给 FCC 的文件中，该公司表示，使用大于 12 英寸的望远镜（许多天文学家都可以使用）观测 Eärendil-1 可能对人眼不安全。不过，它补充说，这种观测“不太可能……导致严重伤害”，因为卫星并非持续保持高亮度。
Currently there is no global entity that could regulate satellites such as these, so approval falls to national regulators such as the FCC in the US. Michelle Hanlon, a space lawyer at the University of Mississippi’s School of Law, says there are “real benefits” to the plans proposed by Reflect Orbital. 目前还没有全球性机构可以监管此类卫星，因此批准权归属于美国 FCC 等国家监管机构。密西西比大学法学院的太空律师米歇尔·汉隆（Michelle Hanlon）表示，Reflect Orbital 提出的计划确实有“实际好处”。
“It could extend the productive hours of solar facilities and provide light in remote areas or after a disaster,” she says. However, the “legal basis is less clear than the technology,” she says. The FCC “does not have authority to license or regulate the operation of the solar reflector itself.” It can only authorize the use of radio frequencies to communicate with the spacecraft. “它可以延长太阳能设施的生产时间，并在偏远地区或灾后提供照明，”她说。然而，她指出，“法律基础不如技术基础清晰”。FCC “无权许可或监管太阳能反射器本身的运行”。它只能授权使用无线电频率与航天器进行通信。
That means Reflect Orbital will need permission on a national and local level to reflect sunlight onto the ground, but if the beams spread as much as Kocifaj and his team predict, “the company could need approvals in more than one jurisdiction,” she says. 这意味着 Reflect Orbital 需要在国家和地方层面获得许可才能将阳光反射到地面，但如果光束的扩散程度如科西法伊及其团队预测的那样，“该公司可能需要在多个司法管辖区获得批准，”她说。