This volume includes original papers presented at the 4th Symposium on Satellite Dynamics held at the XII Annual Plenary Meeting of COSPAR. At a time where it might be thought that very few problems were left un solved in celestial mechanics, we discover that new and more challenging questions must be answered. The pre cision of observations reaches the centimeter level and physical phenomena which had been disregarded come into play. We need a better treatment of atmospheric drag, radiation forces, and a better knowledge of the earth's gravitational field. Time has to be precisely defined as well as reference systems, including improved values for precision and nutation. The question of resonances introduced by nonzonal harmonics was to be carefully in vestigated. Numerical integration techniques must be optimized and means of controlling their errors improved. Analytical techniques must be made appropriate for com puter processing. Presently existing methods of solu tions of differential equations of interest to celestial mechanics are getting cumbersome as all these new facts come to light. It is clear that entirely new and more effective methods are necessary. These methods must, among other requirements, take into account the essential nonlinear character of the equations. Finally, the mo tion about the center of mass of a satellite is becoming an essential need for the thorough understanding and de scription of the orbital motion.

Inhalt
Analytical Theories of the Motion of Artificial Satellites.- Time Elements.- An Estimation Procedure for Orbit Determination, Using the K. S. Transformation.- Importance of the Moon-Earth Coupling Effect in the Motion of an Artificial Satellite: Semi-Analytical Computed Solution of This and Similar Problems.- Numerical Methods of Orbital Dynamics.- J-Adaptive Estimation with Estimated Noise Statistics.- France: Importance of the Coupling Effects Between Earth Potential Harmonics in the Motion of an Artificial Satellite. Computed and Checked Solution of This Coupling Problem. The Case of J7.- On the Comparison of Numerical Theories of Orbital Motion.- Stabilization and Real World Satellite Problem.- Orbit Determination in the Presence of Atmospheric Drag Errors.- Literal Algebra for Satellite Dynamics.- A Comparative Study of the Calculation of Partial Derivatives in Space Dynamics.- Resonance Phenomena at Rotations of Artificial and Natural Celestial Bodies.- The Rotational Motion of a Satellite and Atmospheric Density Determination.- Satellite Attitude Control with Desaturated Rotors.- On the Stability of Spinning Flexible Satellites.- Non-Gravitational Forces in Satellite Dynamics.- Solar Radiation Pressure and Balloon Type Artificial Satellites..- Optimal Impulsive Interplanetary Transfers.- On the Effect of Earth Radiation Pressure in the Motion of Pageos. Comparisons Between Different Models.