The geosynchronous orbits are high enough that atmospheric drag isn't a factor. Only the lunar and solar perturbations are and they must simply be not enough to move a satellite into the operation orbit range. Or perhaps at that distance the perturbations have a tendency to move the satellite even further away from the Earth. I don't know why a higher orbit is chosen vs a lower one. Since the manuevers are done at the end of life -- when there is little fuel remaining -- often it is chancy whether the push to the graveyard orbit can be done. It may be that a push to a high orbit takes less energy and so is more likely to succeed. Robert Fenske, Jr On Wed, 7 Dec 2011, Dale Ireland wrote: > Why is the "graveyard" 135 miles higher than the active satellites? If the > satellite becomes totally unoperational won't it eventually drop, possibly > uncontrolled, back down through the geo belt? Why wouldn't they make the > graveyard 135 miles lower than the belt rather than higher? Are there other > forces involved? > Dale _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-l
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