A single nuclear detonation at a high enough altitude could disable 99 percent of low-Earth orbit satellites within a month. Researchers at the University of Wisconsin–Madison and Princeton University stated this in a pre-print study.
More than 13,000 satellites circle the planet in low-Earth orbit. They form the foundation for weather forecasting, telephone and data communications, and internet services.
Researchers simulated a 1-megaton nuclear explosion 500 kilometers above the South Atlantic near an anomalous region where Earth’s magnetic field is unusually weak. Conditions in this area magnify blast effects by trapping radioactive particles in space.
The calculations incorporated 13,300 active spacecraft in low-Earth orbit as of January this year. A blast in that region would disable 25 percent of the entire fleet after one day.
That figure would rise to 78 percent at the end of day three. It would reach 98 percent after a week and hit 99.4 percent by day 15.
Spacecraft equipped with strengthened radiation protection would still see 99.3 percent of all satellites disabled within 30 days. Deploying a weaker 100-kiloton warhead means disabling 99% of satellites would take about a year, the authors estimate.
“Electrons from radioactive fission-product decay became trapped in Earth's magnetic field, creating an artificial radiation belt that damaged satellites,” lead author Zach Petersen and his team explained. This creates an artificial radiation belt that repeatedly exposes spacecraft as they traverse their orbits.
Unlike the prompt burst, a trapped belt repeatedly exposes spacecraft as they pass through it. A comparable event today would occur in a much more densely populated orbital environment.
Zach Petersen, University of Wisconsin–Madison
Radiation is not the only hazard. As satellites lose maneuverability, the risk of collisions increases sharply.
Researchers estimated that about 20 major collision events can be expected within two years of the blast. Disabled satellites lose their maneuverability.
That loss sharply increases the risk of collision with other orbital objects. After 10 years, those collisions would leave roughly 3,900 new pieces of space debris in orbit.
Continued collisions among long-lived objects could sustain debris production on century timescales.
Historical precedent exists for nuclear explosions causing devastation in space. The Starfish Prime test had lasting effects on low-earth orbit during the Cold War.
That explosion disabled several satellites at the time.
The preprint paper is available on arXiv.
We must do everything we can to prevent this from ever happening.
Study researchers
Earlier coverage: Astrophysicist Warns Large Object Collision Would Destroy ISS
