Author : Robert J. Naumann
Publisher : Unknown
Page : 40 pages
File Size : 42,6 Mb
Release : 1963
Category : Aerodynamics
ISBN : NASA:31769000422223
Observed Torque-producing Forces Acting on Satellites by Robert J. Naumann Pdf
In addition to the forces that influence the motion of the center of mass of a satellite, various forces are also present which influence the motion about the center of mass. These torque-producing forces may result in a change in satellite orientation that affects the thermal balance, operation of solar cells, various scientific measurements, and drag forces. This latter effect results in a coupling between the equations describing the orientation with those describing the orbital motion. Therefore, strictly speaking, the orientation problem is part of the orbital problem. To solve the orientation equations it is necessary to determine the nature of the torque-producing forces. This is done by observing the change in orientation of several Explorer satellites where the drag force is sufficiently small so the orbital dependence on orientation is negligible. It was found that the permanent magnetic moments in the satellites were the dominant effect responsible for the observed changes in orientation. Gravitational torques are also significant. The changes in orientation of the satellites considered were explained extremely well by these two effects, hence it is conculed that other effects are not significant for similar satellites. Various approximations used in this study greatly reduce the effor required to integrate the orientation equations and do not require the simultaneous solution of the orbital equations. The findings, however, are applicable to the simultaneous solution of both the orbital and orientation sets of equations.
