There are over 40,000 pieces of tracked space debris, and while many occupy low-Earth orbit, there are a large number of objects whose orbits extend many thousands of miles/kilometers away from the Earth. With enough objects in low-Earth orbit, a solar flare will potentially disable them, leading to not only a collision, but a chain reaction of collisions. In the worst-case scenario, Kessler syndrome becomes a real risk. (Credit: NOIRLab/NSF/AURA/P. Marenfeld)

Will Musk’s Starlink satellites lead to Kessler syndrome?

Space weather poses a tremendous threat to all satellites, knocking all computer systems offline. Is that a recipe for Kessler syndrome?

Over the course of the 2020s and 2030s, the night sky and the volume of space that surrounds the Earth are both poised to become very different than they’ve been for all of human history. As of 2019, all of humanity had launched an estimated total of between 8,000 and 9,000 satellites, where approximately 2,000 of them were still active back then, mostly in low-Earth orbit. As many companies now scramble to provide worldwide 5G coverage from space — led most prominently by Elon Musk’s and SpaceX’s Starlink, which has by far the most satellites — humanity is now beginning to enter the era of satellite mega-constellations.

As of today in 2023, however, there are nearly 9000 active satellites, with active Starlinks making up the overwhelming majority of them: 4755 out of the 8647 active satellites, or 55% of them. While media coverage has largely focused on only one detrimental effect so far — the damage that these satellites have already caused and are still causing to astronomy — there’s a second consequence that could be even more disastrous over the long-term: Kessler syndrome. With tens or even…