In 1978 a NASA scientist ran the numbers and found something terrifying: put enough junk in orbit and collisions start breeding collisions, faster than anything can decay. Cross that threshold and low Earth orbit becomes an impassable shell of shrapnel — no satellites, no GPS, no way out. Two real collisions later, experts are arguing about whether the cascade has already begun.
The clear explainer: over 100 million pieces of debris, most moving faster than 10,000 mph, and the feedback loop that could make each collision spawn the next.
A visual breakdown of how a single collision at orbital velocity turns one dead satellite into thousands of new lethal projectiles.
The expert disagreement laid bare: some call the 2009 Iridium–Cosmos crash 'the opening move' of the cascade; others say it hasn't started. Even Kessler admitted the term never had a strict definition.
Where the science meets the blockbuster. The film compresses a decades-long cascade into 90 minutes — but the underlying threat, and China's 2007 anti-satellite test, are entirely real.
A deeper video look at the worst-case timeline — the altitude bands most at risk and what a runaway cascade would actually do to the orbits we depend on.
The peer-reviewed reckoning: how the loss of orbit would ripple into aviation, power grids, hospitals, farming, and defense — and why 'space debris recycling' might be part of the escape plan.
The full reference on Donald Kessler's 1978 paper, the critical density threshold, and the cleanup missions now racing to keep the sky open.