Astronomers Call Out Threat Posed By Massive Increase in Orbiting Satellites

The space around Earth is a lot more congested than it was just a few years ago, and many in the astronomical community are growing concerned. An international team of astronomers issued a dire warning this week, calling the proliferation of satellite megaconstellations an “unprecedented global threat to nature.”

The researchers’ arguments are laid out in a series of studies and commentary pieces published in Nature Astronomy. Perhaps the most tangible threat from increased satellite presence is that collisions become more likely. There have already been several close calls that have prompted space agencies to devise new communication protocols, but there’s only so much you can do when new satellites are being launched by the dozen. Since 2019, the number of satellites has more than doubled, thanks mainly to SpaceX deploying its Starlink satellite internet system, and several other companies are planning to launch a similar number of orbiting craft.

Not only does this increase the likelihood of a collision, but those collisions could quickly spiral out of control. Even small pieces of debris in orbit are moving fast enough to destroy satellites and spacecraft. According to researchers, a collision chain reaction, sometimes called Kessler syndrome, is becoming more possible with every launch.

There’s also the issue of satellites interfering with astronomical observations, something multiple teams have complained about ever since the first batches of Starlink satellites appeared in low-Earth orbit. Despite promises from SpaceX CEO Elon Musk that its new satellites would be less reflective, astronomers still regularly see bright streaks from the constellation crisscrossing images (see above).

The Vera C. Rubin Observatory in Chile.
Credit: Rubin Obs./NSF/AURA

An analysis of how the night sky will change over the coming years doesn’t paint a rosy picture. A model based on the under-construction Vera Rubin Observatory suggests that the darkest parts of the night sky will be 7.5% brighter in 10 years, reducing the number of visible stars by the same margin. That would add at least a year to the telescope’s survey, costing the project $21.8 million.

Astronomers are also calling out a more existential threat posed by additional megaconstellations. The night sky won’t look the same when you look up, even in isolated places where today’s sky looks like it did centuries ago. For the entire history of humanity, we’ve gazed at the stars to find meaning. They helped early navigators find their way and formed the basis for stories and myths that still survive. By changing the sky, maybe we are losing something important.