<h2>AAS 97-123</h2>
<h2>EAST-WEST STATIONKEEPING OF SATELLITE ORBITS WITH RESONANT  TESSERAL HARMONICS                                                                   </h2>
<h4> T. A. Ely and K. C. Howell, Purdue University                                                                                                                            </h4>
<h2> Abstract </h2>
 Satellite orbits that are eccentric and inclined with near-repeating ground tracks  can exhibit complex dynamical motions which are typically in resonance with  multiple tesseral harmonics.  Depending on the resonance, inclination and  eccentricity, the tesseral interactions can produce complex motions.  The motion  encountered can have a significant impact on the east-west stationkeeping process.   The classical stationkeeping algorithm is potentially non-convergent in complex  phase space regions.  A proposed new method, developed to remain stable in these  regions, retains the 'grazing' strategy of the classical algorithm but adapts to  the environment to ensure stability of the process.