The CRASH Clock is a newly proposed metric that estimates how quickly a catastrophic satellite collision could occur if collision-avoidance or situational awareness fails. Researchers find the clock could be as short as 2.8 days in an extreme disruption—down from about 121 days in 2018—reflecting rapid growth in megaconstellations. The finding underscores the need for better tracking, design standards, and international rules to reduce collision and environmental risks in low-Earth orbit.
New 'CRASH Clock' Warns Catastrophic Orbital Collision Could Happen In Days, Not Years
Researchers attempted to quantify the risk of a catastrophic collision in orbit by coming up with an alarming new metric.
In 1978, NASA researcher Donald Kessler and colleagues warned that a single satellite collision could trigger a cascade of follow-up impacts, forming a long-lived belt of debris around Earth. That hypothetical chain reaction—now known as Kessler syndrome—remains one of the clearest existential risks to safe space operations.
An international team from Princeton University, the University of British Columbia and the University of Regina has now proposed a way to quantify how quickly a catastrophic collision could occur under degraded conditions. In a paper that has not yet been peer-reviewed, they introduce the Collision Realization and Significant Harm (CRASH) Clock, a metric that estimates the time until a catastrophic collision if satellites cannot perform collision-avoidance maneuvers or if situational awareness is severely impaired.
What the CRASH Clock Says
The researchers find that in an extreme disruption—for example, a powerful solar storm that disables communications and tracking systems—the CRASH Clock could shrink to as little as 2.8 days. Put another way: if orbital platforms suddenly lost the ability to track and dodge one another, a potentially catastrophic collision might occur in under three days. By contrast, using the same metric the team estimates the CRASH Clock was roughly 121 days in 2018, before the recent megaconstellation build-out.
“There is substantial potential for current or planned actions in orbit to cause serious degradation of the orbital environment or lead to catastrophic outcomes, highlighting the urgent need to find better ways to quantify stress on the orbital environment,” the authors write.
The team emphasizes that while large collisional cascades can take decades or centuries to fully develop, a single collision can immediately produce substantial operational stress—even if it does not trigger a runaway debris belt. They liken the near-term effect of a major collision to a large environmental disaster: operations could continue, but under altered, more hazardous parameters.
Why The Risk Has Grown
The number of objects in low-Earth orbit (LEO) has surged in recent years. A recent study cited by the authors estimates objects in LEO rose from about 13,700 in 2019 to well over 24,000 in 2025. Much of that increase comes from commercial megaconstellations launched to deliver global broadband.
SpaceX’s Starlink program is the largest single contributor: the company has launched more than 10,000 Starlink satellites and operates several thousand active units. Because satellites have finite lifetimes and can be lost to failures or collisions, operators report losing one to two satellites per day on average across large constellations, which adds to the dynamic and sometimes unpredictable traffic in LEO. Recent operational incidents—such as a reported tumbling Starlink craft that lost contact and is expected to reenter within weeks—underscore the day-to-day risks.
Other commercial and state actors, including Amazon and entities such as the China Aerospace Science and Industry Corporation, plan or operate large constellations as well, meaning the number of active objects in orbit is expected to keep rising.
Broader Consequences
Beyond collision risk, megaconstellations have already affected astronomy—producing bright streaks in telescopic images—and raised environmental concerns. When satellites reenter, materials such as aluminum oxide or other particulates could be released high in the atmosphere, potentially affecting the upper atmosphere and ozone chemistry. These ancillary impacts have prompted calls for stronger oversight, stricter design and disposal standards, and improved international coordination.
What Can Be Done?
Mitigating the risk highlighted by the CRASH Clock will require multiple measures: better space situational awareness and data-sharing among operators; more robust collision-avoidance protocols; stricter design-for-demise and end-of-life requirements; improved resilience against space weather; and international agreements that set norms and enforcement mechanisms for orbital safety.
Note: The CRASH Clock analysis comes from a paper that is not yet peer reviewed and represents one proposed metric for quantifying orbital stress. Still, it provides a compelling wake-up call: the orbital environment is becoming more fragile, and certain disruptive events could sharply accelerate the timeline to a major collision.
