Reactionless Thrust Station Keeping at L2

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Revision as of 16:54, 14 November 2008 by Farred (talk | contribs) (reactionless thrust)
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The L2 point is defined for two bodies in circular orbit about each other. The sun-Earth and Earth-Luna systems do not exactly match the definition, but they come close enough that the model is a useful model. Calculations [1] put the Earth-Luna L2 point at 64500 km beyond Luna's center. If masses are depended from this point along a line connecting the centers of mass of Luna and Earth, one depended away from Luna and one toward Luna, these masses can be adjusted to provide thrust toward or away from Luna. If one mass is depended by tidal force to 5.25*10^7 meters from Luna's center and another depended by tidal force to 7.65*10^7 meters, then when these masses are both reeled in 2*10^6 meters toward L2 there is a balance of forces needed to adjust these masses and the net acceleration on the system changes by an 8% of the previous acceleration on the depended masses directed upward. This force results from a balance of the gravitational and centripetal forces. By combination with a pair of angular rate control wheels at L2 this can provide all of the station Keeping needed by a satellite at L2.

  • Reference
  1. calculations by Farred as to be shown in discussion