91av

WHAT do you do with a fleet of mobile phone satellites that nobody wants to
use? Why, turn them into a space weather monitoring network, of course.

Earlier last year, it looked like the 66 satellites of the Iridium network
would be ditched in the ocean because so few consumers wanted to cart around the
bulky handsets needed to communicate with them. But last November a company
called Iridium Satellite offered to buy the network
(91av, 25 November, p 11).
The company has now signed a deal with the US military to
provide phone services.

But a group of physicists led by Brian Anderson of Johns Hopkins University
in Baltimore has also expressed an interest because each of the satellites
carries a magnetometer. These instruments can monitor space weather, the stream
of particles from the Sun that floods the Solar System. “Essentially, we now
have a network of weather stations in space,” Anderson says.

The solar wind dumps gigawatts of power into the Earth’s atmosphere and that
power can increase several fold in less than an hour in the wake of violent
solar flares. Such solar storms can knock out satellites and disrupt power
grids.

A network of ground-based radar stations called SuperDARN (Dual Auroral Radar
Network) already keeps track of the electric field surrounding the planet. But
researchers will also use readings of the magnetic field from the instruments on
board the Iridium satellites to calculate the power of solar storms. “The plan
is to develop a knowledge base that will enhance other forecasting techniques,”
Anderson says. The contract with Iridium Satellite lasts at least two years.