Like distance from the Earth. And do some of them “sit” in one place, like always over North America?

  • AbouBenAdhem@lemmy.world
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    9 months ago

    Others have mentioned geosynchronous satellites as examples that can just sit in one place, but they can only do so over the equator—not directly over North America as per your question. (They would still be visible from North America, bu they would appear to the south instead of directly overhead.) Geosynchronous orbits can be inclined relative to the earth’s axis, in which case they could pass directly over North America; but they would have to spend an equal amount of time over the southern hemisphere (without moving significantly east or west).

    • litchralee
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      9 months ago

      but they would have to spend an equal amount of time over the southern hemisphere

      There are some highly eccentric orbits which are heavily tilted so that, time-wise, they spend more time in one hemisphere than the other, by tracking farther away from the earth when slowly overlooking the northern hemisphere, and then getting closer to the earth when tracking the southern hemisphere, faster. The Molniya orbit is one example. There is a diagram showing how much time the orbit spends in each hemisphere.

      For use in telecommunications, the fact that the satellite gets farther away is usually acceptable, although this wouldn’t be as good for a spy satellite.