US satellite protection scheme could affect global communications
http://www.physorg.com/news74778465.html

A proposed US system to protect satellites from solar storms
or high-altitude nuclear detonations could cause side-effects
that lead to radio communication blackouts, according to new research.

If activated, the "radiation belt remediation" (RBR) system
could significantly alter the upper atmosphere, seriously
disrupting high frequency (HF) radio wave transmissions and
GPS navigation around the world.

The remediation system aims to protect hundreds of low
earth-orbiting satellites from having their onboard electronics
ruined by charged particles in unusually intense Van Allen
radiation belts "pumped up" by high-altitude nuclear explosions
or powerful solar storms.

The approach, which is being pursued by the US Air Force
and the US Defense Advanced Research Projects Agency,
involves the generation of very low frequency radio waves
to flush particles from the radiation belts and dump them
into the upper atmosphere over one or several days.

The scientific team from New Zealand, UK and Finland
calculate that Earth's upper atmosphere could be dramatically
affected by such a system, causing unusually intense HF blackouts
around most of the world.

The disruptions result from a deluge of dumped charged particles
temporarily changing the ionosphere from a "mirror" that bounces high
frequency radio waves around the planet to a "sponge " that soaks them up.

The research is published in the August edition of the
international journal Annales Geophysicae. The researchers
suggest that policymakers need to carefully consider the
implications of remediation.

If the intense radiation belts resulted from a rogue state
detonating a nuclear-tipped missile in the upper atmosphere,
using such remediation technology would probably be acceptable
to the international community, regardless of any side effects.

However, using the system to mitigate the lesser risk to
satellites from charged particles injected by naturally
occurring solar storms should be considered more closely.
The impact of the disruption to global communications
needs to be weighed carefully against the potential gains.

Source: British Antarctic Survey