A System for Inertial Experiment Pointing and Attitude Control
Author: Peter R. Kurzhals
Publisher:
Published: 1966
Total Pages: 76
ISBN-13:
DOWNLOAD EBOOKA system for inertial experiment pointing and attitude control (designated SIXPAC) of future manned spacecraft has been investigated. The SIXPAC concept consists of three double-gimbaled control moment gyros aligned with the axes of the spacecraft, and derives its control torques from precession of the gyro wheels. This system is readily mechanized, has inherent redundancy, and should provide a wider range of attitude control for manned spacecraft than the gyro systems previously considered. The SIXPAC can provide both the large range of control torques and the fine attitude holds associated with spacecraft experiments such as earth-surface tracking and mapping, photographic missions, and astronomical observations. Periodic aerodynamic and gravity-gradient torques can also be counteracted by the proposed system. Redundancies inherent to the three-gyro arrangement further allow reduced spacecraft control in case of failure or shutdown of one of the three gyros. The complete equations of motion for a spacecraft with the SIXPAC were developed, and were integrated numerically on a digital computer for an example mission with a possible Apollo applications concept. Results of this computer study were used to evaluate the spacecraft and control system response and to determine the power and fuel consumption of the SIXPAC. Characteristics time histories of the attitude and angular rates of the spacecraft are presented for a number of experiments that have been proposed for typical Apollo applications missions, and the performance of the gyro system is analyzed during the control tasks associated with these experiments.
