Findings may save satellites

Rory Gamble
Rory Gamble
Research by University of Otago PhD student Rory Gamble has helped give geophysicists crucial clues about how to counteract the damaging effects of solar flares on orbiting satellites.

During an active solar period, solar flares disturb the magnetic field surrounding the Earth and cause a build-up of electrons, which can damage the circuitry on board spacecraft.

A solar eruption in 2006 disrupted the Global Positioning System, a satellite-based navigational system used widely by the military, scientists and civilians.

Mr Gamble said previous research had suggested radio waves could be used to dissipate the build up of such charges, by discharging electrons into the atmosphere, but scientists had always believed this would have to be done from space.

"It's been very exciting," Mr Gamble said this week of his research.

"It shows a way to protect those satellites."

His latest research, reported last week in Geophysical Research Letters, a scientific journal, has shown the protection can be provided by beaming radio transmissions from the surface of the Earth.

The collaborative research involved work by five French scientists as well as by Mr Gamble and his PhD supervisor, Otago University physicist Dr Craig Rodger.

Mr Gamble and colleagues were using the French-owned research satellite known as Demeter (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions) to investigate the behaviour of the magnetosphere when they picked up anomalies over the Northwest Cape military transmitter in Western Australia.

"It became very clear as soon as we started looking at it."

The scientists determined that the very low frequency transmitter was having "quite a significant effect" on electrons in the radiation belts in the magnetosphere.

"[It caused] those electrons to crash into the top of the atmosphere and be removed from the radiation belts."

This was the first study to show humans could control electrons in the magnetosphere from Earth, he said.

Specially-designed radio transmitters could bathe the sky in radio waves, to dissipate the electrons, and allow a safer passage for satellites.

Many transmitters based in many countries would probably be needed to provide protection for the world's satellite network, but exact details had yet to be determined, he said.

Scientists have said the peak of the present sunspot cycle will come in late 2011 or early 2012 - potentially affecting airline flights, communications satellites and electrical transmissions.

Satellites in space can be affected by changes in solar radiation, scientists say.

 

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