Particles that damage satellites can be flushed out of orbit

“Hot” or “killer electrons”, as such harmful particles are also known, tend to be dragged by Earth’s magnetic field into one of two doughnut-shaped belts of radiation that circle the planet. For decades scientists have wondered if these belts could be emptied of their electrons on command, a process they call radiation-belt remediation (RBR). In recent years, work on RBR has accelerated, and the progress made has encouraged yet more experimentation. Much of the R&D is undertaken, in some cases discreetly, by America’s departments of defence and energy.