Computation of spacecraft signal raypath trajectories relative to the sun

A computer program (CTS 41B) used to determine the trajectory of a spacecraft signal raypath was updated to increase its usefulness during solar conjunctions (CTS 41C). The closest point of approach of the raypath to the sun is projected onto the surface and the solar latitude and longitude calculated. A sample computation and plots are given for the 1976 Viking solar conjunction. Eventually it may be possible to predict the communication link performance degradation in the near sun region due to solar activity.