Accession Number : AD0673219

Title :   EFFECT OF THE NEAR-EARTH ENVIRONMENT ON THE ATTITUDE OF A SLOWLY SPINNING MULTIBODY SATELLITE (X-RAY EXPLORER).

Descriptive Note : Technical memo.,

Corporate Author : JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB

Personal Author(s) : Anand,D. K. ; Whisnant,J. M. ; Sturmanis,M.

Report Date : JUL 1968

Pagination or Media Count : 35

Abstract : This paper considers the effects of the near-earth environment on the dynamics of a slowly spinning satellite (1/12 rpm). A rotor is employed to obtain the necessary angular momentum parallel to the spin axis. The satellite has four solar paddles and an eddy current nutation damper. The objective of the satellite is to detect and chart X-ray emitting sources in the celestial sphere. The dynamics of the spacecraft are investigated by numerically integrating the nonlinear equations of motion which include external perturbations. The effects of the magnetic, gravity-gradient, and solar environments on the attitude are small. However, the effect of aerodynamic torques is seen to be significant. Variations in spin rate and spin axis drift are obtained for different atmospheric conditions and physical parameters. Also, the pointing error to the precession axis referred to a fixed star is established. (Author)

Descriptors :   (*SCIENTIFIC SATELLITES, ATTITUDE CONTROL SYSTEMS), X RAYS, ASTRONOMY, SPINNING(MOTION), AERODYNAMIC CHARACTERISTICS, DAMPING, ERRORS, DRIFT, NUMERICAL METHODS AND PROCEDURES, PERTURBATION THEORY, EQUATIONS OF MOTION

Subject Categories : Unmanned Spacecraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE