Can space mirrors cool Earth?

Over 30 years ago, a Russian satellite carrying a 80-foot-wide mirror was launched into outer space as part of a project extending daylight hours in Siberia. Today, a much more formal version of the operation emerges with Reflect Orbital, a private space technology company based in California.

Reflect Orbital
Since 2021, Reflect Orbital has worked on using mirrors to reflect sunlight into areas that otherwise would remain dark. Search and rescue, public events, and construction projects are tremendous benefits cited by the company’s cofounder and CEO Ben Nowack. In 2025, Reflect Orbital announced their Eärendil project. Named after a Lord of the Rings character, the project aims to use space mirrors to direct heat from the sun away from the Earth.

The Eärendil-1 Satellite
Space mirrors are key to Solar Radiation Management (SRM), a theoretical method which aims to redirect light and UV radiation in order to reduce the impact of climate change. The ultimate goal of SRM is to consistently redirect enough heat that balances out global warming caused by the burning of greenhouse gases. The New York Times claims that Reflect Orbital hopes to achieve this through the launch of 50,000 space mirrors, including ones of significantly larger sizes.

The first launch of the Eärendil-1 satellite, a demonstration satellite containing an 18 meter by 18 meter foldable mirror, was approved by the Federal Communications Commission in early July. According to Space Daily, once in low Earth orbit, Eärendil-1 will unfold and be programmed to direct light to a specified location on the ground. The demonstration satellite will be launched as a single test of the concept.

Opposition
Since the license was issued, there has been major speculation on the viability of this satellite. According to the New York Times, astronomers and wildlife experts among others strongly oppose the Eärendil satellites. They claim that astronomical changes like the ones caused by the Eärendil satellites may alter circadian rhythms, the fundamental schedules of light and heat that guide humans, animals and plants throughout the year. As such, the Eärendil satellites would result in significant alterations to life all across Earth if implemented.

Beyond scientific issues, policy implications of this approval are troubling as well. Domestically, the American Astronomical Society suggested that the launch of Eärendil-1 is not advantageous to American taxpayers, since their earnings are used to fund space programs with uncertain results. Additionally, Samantha Lawler, an astronomer based in Canada, expressed concern for the power of a single nation in altering outer space, a realm that significantly impacts every nation on the planet.

As the Eärendil-1 reaches low Earth orbit, its performance will be the center of attention for astronomers, climate-conscious citizens and policymakers across the world, watching to see how effective this method is. As more technologies are proposed to address impending climate issues, demonstrations and tests like Eärendil-1 should be met with care and caution to ensure policy compliance. As governments and companies explore increasingly ambitious responses to climate change, technologies like Eärendil-1 highlight a growing debate: how far should humanity go in attempting to engineer the planet?