A cataclysmic event could cause all of Earth’s satellites to crash within days

Humanity has invested heavily in satellites, and not just in terms of money. Yes, the most expensive satellites can cost nearly a billion dollars, but the big investment comes in terms of our reliance on orbiting technology. Television broadcasts, navigation systems, weather forecasts, and many types of financial transactions all depend on satellites to function. If all of Earth’s satellites were to suddenly shut down, international communications systems would begin to fail, traffic would grind to a halt, clocks would be out of sync, and global supply chains would collapse. It’s a scenario fit for a disaster movie, but unfortunately, it’s also a very real threat. It would take as little as a solar storm or a single software glitch to destroy every satellite in less than a week.

The number of satellites in orbit is increasing rapidly, especially after the introduction of SpaceX’s Starlink satellites. As of January 2026, there are about 15,000 satellites in orbit, about two-thirds of which are Starlink. As space around Earth becomes more crowded, satellites need to perform increasingly frequent maneuvers to avoid crashing into each other. It’s gotten to the point that SpaceX alone is performing collision avoidance maneuvers every two minutes. However, if SpaceX or any other satellite operator loses contact with its technology due to a solar storm or software error, they will not be able to perform the necessary interceptions. This can set off a domino-like chain of crashes that bring down all of Earth’s satellites within days.

Read more: How NASA is planning to deorbit the ISS

Scientific efforts in measuring the risk of satellite collisions

Scientists have been concerned about this risk since the first satellite launches at the height of the space race. In 1978, NASA researcher Donald Kessler published a paper in the Journal of Geophysical Research, warning of the danger of satellites colliding with each other and creating a debris belt around Earth that would block our access to space. This in turn gave rise to the term “Kessler syndrome”, a vaguely defined scenario where low-Earth orbit becomes so crowded with satellites that a single collision triggers another and another. Lose one satellite… lose them all.

Kessler created mathematical models to demonstrate the risk, but apparently, that didn’t stop companies from building more and more satellites. In light of the new reality, Princeton University graduate student Sarah Thiel and her colleagues developed a new way to measure risk, called the Collision Realization and Significant Harm (Crash) Clock. CRASH Clock uses satellite position data to estimate the time required for a catastrophic collision between satellites if the ability to perform avoidance maneuvers is lost. As of the writing of this article, the crash clock sits at just 5.5 days. It takes less than a week for satellite engineers to avert disaster. What’s even more alarming is how quickly the risk has escalated. In 2018, before Starlink’s satellite megaconstellations were introduced, the CRASH clock was at 164 days.

Past accidents serve as warnings

The crash clock is perhaps the clearest warning of how quickly we are approaching a Kessler syndrome scenario. In less than a decade, the clock went from five and a half months to just five and a half days, dangerously cold. The risk is not only imaginary. A growing pattern of actual collisions and outages is putting the vulnerability of our satellite system on display. Studies show that solar storms are already interfering with some satellites, increasing the drag forces they experience in orbit. This does not bode well for the possibility of an extra-strong solar storm, for which there is a preference.

On May 19, 1998, the Galaxy IV communications satellite failed after a period of intense solar flares. The loss of satellites disabled 80-90% of all pagers on the North American continent. It was the late 90s, and pagers ruled the world, especially in the medical field, where doctors and nurses depended on them for emergency calls. Suddenly, those critical medical professionals could not be reached. Meanwhile, NPR, CBS, and the Chinese Television Network lost their signals. Fortunately, services were able to reconnect via other satellites, but that was about 30 years ago, and space was much less crowded. If the same event happened today, the Galaxy IV would not only eject, but probably crash into nearby satellites, bringing everything down like a house of cards.

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