ANALYTIC DETERMINATION OF CAMERA OPERABILITY STATUS CONSIDERING DYNAMIC SOLAR CONSIDERING DYNAMIC SOLAR CONFLICT FOR THE RADIO ASTRONOMY EXPLORER SATELLITE

摘要

An analytic method is formulated which is capable of predicting times unsuitable for useful vidicon camera operation for the Radio Astronomy Explorer satellite due to solar inclusion within the cameras' conical fields of view. The vidicon cameras, mounted within the central hub of the gravity-gradient-stabilized space craft, measure the 750-foot cruciform antenna boom tip positions, providing information of importance in determining the flexible Vee-antenna patterns so as to enable reduction of experimental radio astronomy data as well as for dynamics studies. A computational algorithm is developed which calculates, for each time point, the angle between the sun line referenced to the spacecraft hub center and the camera field of view axis, for each of the two vidicons positioned to observe the deformations of the upper (i.e., directed toward the galactic sphere) booms. These calculations require knowledge of certain spacecraft configuration parameters as well as ephemerides of the sun center position and spacecraft hub center position and velocity components.