Physicists To Help Unravel Mysteries Of Near Space

3 May 2002

Otago Physicists To Help Unravel Mysteries Of Near Space

Otago space researchers are taking part in an international experimental effort involving a satellite launched from the International Space Station.

While the Russian satellite counts the number of highly charged particles heading from the Van Allen Belt, which is the zone of high-intensity radiation surrounding the planet, towards the ionosphere above New Zealand, University of Otago Space Physicists will be taking ground-based readings of these particles' effects on the ionosphere.

The Otago researchers hope that a comparison of the two sets of data will help shed light on the "incredibly complicated processes" through which the particles, which make up the radiation belts in near space are precipitated into the Earth's atmosphere, says space physics researcher Dr Craig Rodger.

The Kolibri-2000 microsatellite was launched from the International Space Station (ISS) on March 19 2002 and due to atmospheric friction is expected to burn up this Saturday. As well as the particle counters, it is carrying equipment to make electric and magnetic field measurements. In the brief period before it burns up, groups in New Zealand, Australia and the US are taking ground measurements in collaboration with the Russian Space Agency, IKI, says Dr Rodger.

The Otago team has booked the final three 20-minute recording sessions with the satellite as it passes over Dunedin, and they plan to exchange their ground data for the information gathered from space, he says.

"Hopefully the satellite will be able to measure a stream of energetic particles heading towards the atmosphere. Then, with our own measurements of the subsequent ionospheric effects and the timings involved, we should be able to see whether our theories concerning the effect of lightning on these particles are on the right track," he says.

Very low frequency radio waves produced by lightning are known to travel out and remove particles from the belts, and the Otago researchers believe that this method of removal may be much more important than previously thought, he says.

"It's incredibly difficult to find out what's going on in the radiation belts. The data gathered will hopefully provide the sort of 'real world' numbers we need to plug into our calculations. Also, it's a great opportunity to participate in an international programme that will further our understanding of Near Space."

The team took measurements on May 1, 2 and will do so again tonight. Viewing times for the International Space Station, which is following Kolibri-2000 by ten minutes, may be found at: https://neptune.hq.nasa.gov/novis/ISScountrylist.cfm

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