Say no to space mirrors
An unprecedented threat to the night
DarkSky International is closely monitoring and mobilizing against an emerging threat to the nighttime environment: orbital reflectors, satellites equipped with large mirrors designed to redirect sunlight onto Earth after dark. Reflect Orbital, a California-based startup, has received approval from the U.S. Federal Communications Commission (FCC) to launch its first orbital reflector as early as next year, with plans to deploy up to 50,000 by 2035.
Unlike light pollution from the ground, orbital reflectors could redirect sunlight onto virtually any location on Earth, including some of the world’s darkest and most protected places. Although developed and launched by companies in individual nations, these satellites would operate in a shared orbital environment, with potential impacts extending far beyond national borders.
Orbital reflectors: What we know
The concept is by no means new. First experimented with during the Soviet era, orbital reflectors are now being proposed with ambitious claims but little evidence of their real-world effectiveness. From how the technology works to its proposed applications and potential consequences, many questions remain unanswered. Here’s what we know.
What are orbital reflectors, and how do they work?
Orbital reflectors are satellites equipped with large mirrors designed to redirect sunlight back to Earth’s surface after dark. While the ground below is in darkness, satellites orbiting high above can remain in sunlight, allowing their mirrors to reflect that light toward targeted areas on Earth.
Each reflector would illuminate an area several kilometers wide, but only for a few minutes as the satellite passes overhead. Providing sustained illumination would require thousands of satellites working in sequence.
The concept isn’t new. In 1993, a Russian experiment called Znamya 2 briefly reflected sunlight onto Earth. Today, companies like Reflect Orbital propose using the technology to extend solar power generation and illuminate areas at night. However, its effectiveness at scale remains unproven, and the reflected light could be visible far beyond the intended target area.
What problem are orbital reflectors trying to solve?
Reflect Orbital has proposed a wide range of applications for its technology, from extending solar power generation after sunset to supporting nighttime search-and-rescue operations, illuminating industrial and agricultural work sites, and even replacing traditional streetlights. In a public presentation, the company’s CEO, Ben Nowack, also suggested potential military applications for the technology, though he declined to elaborate on how it might be used. (Watch the presentation)
The company has also suggested that customers could purchase reflected sunlight on demand through a smartphone app, potentially allowing paying customers to illuminate vast stretches of land with the ease of flipping a switch.
However, none of these proposed applications has been demonstrated from orbit, and significant questions remain about their practicality, effectiveness, and cost. During a ground-based lighting demonstration near Lone Pine, California, volunteer search-and-rescue crews described the additional illumination as only “marginally better” and raised concerns about whether the cost would make it practical for their operations. (Read more)
While the company has made ambitious claims about the technology’s potential, its real-world benefits, economic viability, and environmental consequences remain largely unproven.
What are the risks of orbital reflectors?
If deployed as proposed, orbital reflectors could introduce light pollution on an unprecedented scale. Reflect Orbital proposes to illuminate areas up to five kilometers (three miles) wide at intensities several times brighter than a full moon, with plans to deploy tens of thousands of satellites to provide sustained illumination.
DarkSky has identified five major concerns:
Orbital debris. Large mirrors in low Earth orbit could increase collision risks and contribute to the growing problem of space debris.
Wildlife and ecosystems. Artificial light at night can disrupt navigation, migration, feeding, and reproduction, threatening biodiversity and the balance of nocturnal ecosystems.
Human well-being. Exposure to artificial light at night can disrupt circadian rhythms that regulate sleep and other biological processes. Viewing reflected sunlight through optical devices may also pose risks of eye damage.
Public safety. Sudden flashes, glare, and sweeping beams of light could threaten night vision and create hazards for pilots, drivers, and observers.
Astronomy. Scattered light could increase skyglow and interfere with astronomical research, while direct illumination near observatories could damage sensitive instruments.
Protect your community from reflected light
DarkSky International is working on creative solutions to address the emerging threat of orbital reflectors. Building awareness is a critical first step, as many people are still unfamiliar with the technology and its potential impacts. You can help by exploring and sharing our articles and resources about Reflect Orbital.
If you’re ready to take your advocacy a step further, DarkSky has developed ready-to-use policy templates to help communities work with local leaders to restrict the purchase of reflected sunlight from orbit. Explore the resources below to learn more and take action.
Ban the purchase of reflected sunlight in your community
Communities can act now to discourage the commercial use of reflected sunlight from orbit. DarkSky has developed ready-to-use policy templates to help advocates and community organizations work with local leaders to establish some of the first legal frameworks restricting its purchase.
We want to know where around the world communities are taking action. Complete the form below to access DarkSky’s policy templates and help us track efforts to protect communities from unwanted illumination.
