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A different pattern

Satellite's deteriorating orbit a boon for South Pole

Normal communications satellites are in geosynchronous orbits (GEO) over the equator. Their position and the earth’s curvature hide them from the North and South Poles. Low Earth Orbiting (LEO) satellites can cover the poles, but only for brief periods of time, which in turn requires more satellites (like the Iridium External Non-U.S. government site constellation, which has 66 satellites). Currently, there is no LEO satellite constellation that has the communications bandwidth South Pole Station needs; not even Iridium can support South Pole requirements.

However, when satellites get old, they begin to stray outside their normal orbit patterns, moving farther north and south. Over 24 hours, a GEO satellite traverses a ground trace that looks like a big “figure 8.” When the bottom of the “figure 8” has an angle greater than 8.5 degrees below the equatorial plane, the satellite becomes visible at South Pole for several hours of its 24-hour orbit. This anomaly provides South Pole personnel access to the Internet and phone calls for the few hours they can “see” the satellite. In Pole vernacular, the “satellite is up.”

Return to main story: Keeping connected.

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Curator: Peter Rejcek, Antarctic Support Contract | NSF Official: Winifred Reuning, Division of Polar Programs