Protecting hundreds of low-Earth-orbit satellites from destruction seems a laudable idea, and the Pentagon wants to do just that. But the scheme could backfire, by shutting down civilian and military communications and impairing GPS signals.
The Pentagon is concerned that a high-altitude nuclear explosion or an intense solar storm could fill near-Earth space with charged particles, crippling the operation of many satellites. It has proposed a plan called 鈥渞adiation belt remediation鈥� to clean it up. The idea is to swamp the charged particles with very low-frequency radio waves. That would create wave-particle interactions that encourage particles to precipitate and fall into the upper atmosphere, where they would do little damage.
However, a study by Craig Rodger of the University of Otago in New Zealand and colleagues has revealed this could affect the electrical properties of the part of the upper atmosphere called the ionosphere, which in turn could severely disrupt radio and GPS transmissions.
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Normally the ionosphere reflects radio waves at frequencies up to about 30 megahertz, but if it was full of charged particles it would absorb radio signals instead. That would shut down long-distance transmission in the 3 to 30-megahertz high-frequency band used by military and civilian communications, Rodger warns. Absorption at higher frequencies could degrade the signal quality and accuracy of the Global Positioning System, he reports in Annales Geophysicae (vol 24, p 2025), an online journal published by the European Geosciences Union.
