Big space mirrors could bring Earth on-demand light — and upend our night sky

Since 1989, astrophysicist Jonathan McDowell has tracked every human-made object in space. McDowell’s meticulously maintained catalog, updated every few weeks, is more comprehensive and detailed than that of most governments. From his front-row seat, he has watched with growing alarm as private companies launched dozens, then hundreds, then thousands of satellites over the last decade.

So when McDowell heard that a space company called Reflect Orbital plans to launch a satellite to reflect the sun’s light onto the night side of Earth, he heaved a deep sigh. The consequences to astronomy could be catastrophic, they say, and the reflected light could threaten human health and safety and disrupt wildlife. In March, the American Astronomical Society petitioned the Federal Communications Commission to deny Reflect Orbital’s request to operate the test satellite.

When the FCC granted approval in July, nonprofit organizations including DarkSky International asked the agency to reverse its decision. The response to Reflect Orbital reflects growing concerns about the crowding of space more generally. The number of active satellites orbiting Earth has ballooned from 2,000 in 2018 to over 16,000 today, McDowell says.

Many more are expected to launch in the years ahead. This traffic jam, along with the proliferation of space junk from dead satellites and discarded rocket stages, has space scientists worried about collisions that could wipe out GPS navigation and other essential tools. The satellites are also a problem for astronomers, interrupting observations by leaving streaks on telescope images.

But there’s not much scientists can do to appeal the launches, says international environmental lawyer Dana Zartner of the University of San Francisco. Space satellite deployments are governed (sometimes loosely) by a patchwork of domestic regulations and international treaties. The Reflect Orbital launch, expected this year, could change that.

The satellite’s unique brightness and the risks it may bring could mark an inflection point in the way we regulate the night sky. The project “amplifies the issue to the point where it’s impossible to ignore,” says astronomer Stephen Hummel of the McDonald Observatory in West Texas. Space law’s roots are planted in the Cold War.