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Homework Help: Geostationary satellite

  1. Apr 12, 2012 #1
    why it's impossible for a satellite in a non-equatorial plane to be geostationary? Explain in terms of gravitational force and centripetal force(If possible show equations and draw diagrams for forces acting on the satellite).
  2. jcsd
  3. Apr 12, 2012 #2


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    Have you given this any thought yourself? Do you understand that the center point of a circular orbit (a focal point of a general elliptic orbit) must at the center of the earth?
  4. Apr 12, 2012 #3
  5. Apr 12, 2012 #4
    Its for my general knowledge.. I wanted to know the satellite motion??
  6. Apr 12, 2012 #5
    It's urgent please reply as soon as possible!!!
  7. Apr 12, 2012 #6


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    There's two steps. One is explaining why the center of the Earth has to be the true focus of the orbital ellipse (or the center of the circle if a circular orbit). The other step is explaining why the orbital plane has to match the equatorial plane (you could have the Earth at the center of your orbit and still have an angle between your orbital plane and the equatorial plane).

    Your drawing does neither. Why would a satellite move in a circle? It might move in a straight line if the Earth didn't exist, but there has to be some reason for the satellite to move in a circle. You'd be better off starting with the satellite moving in a straight line and then explaining why it's path curves.

    The answer to the second part should be pretty obvious with a simple drawing. If there's an angle between the orbital plane and the equator, the satellite will obviously have to move North and South of the equator, even if it could remain at the same longitude (which it can't by the way - it has to move in a figure 8 if there's any inclination in the orbit plane).
  8. Apr 12, 2012 #7


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    The two extremes if one can call them that, is a satellite orbiting on the equatorial plane and one orbiting on the polar plane ( is crossing the north and south pole). And in between are any other number of circullar orbits at an angle to the equatorial plane.

    Obviously a polar orbit cannot be geostationary.
    Not all equatorial plane orbits are geostionary - that would depend upon the altitude of the satellite. ( which by the way is what your question is presumably asking about, but I am not so sure).

    By your diagram, or is that the diagram supplied by the question, the orbit displayed is parallel to the equator and that just cannot happen unless of course the satellite expends fuel and supplies a thrust to conteract the resultant force arising from gravitation and keep it at that plane.

    The question appears not explicite enough to provide a complete and concise answer.

    Depending upon the analysis, a satellite not in a non-equatorial plane but parallel to, can be geostationary so the answer would be Yes it can, and you would not be incorrect.
  9. Apr 13, 2012 #8
    Well the diagram is not from the question! In fact I was trying to picturize the satellite...
    I wanted to know if the Gravitational force makes an angle with the centripetal force(Since Gravitational force acts towards centre of earth and the centripetal force towards the centre of orbit) and if the vertical component GsinQ contributes to the centripetal force???? Can someone bring some enlightenment on this part? Thanks anyways for the help(can someone explain it on a diagram and with equations if there is any)!
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