A logarithmic spiral trajectory is not the optimum trajectory for a solar sailing space vehicle. Investigation of the governing equations showed that the performance of the solar sail depends on one parameter "a". This parameter "a", defined simply as the ratio of radial to tangential forces, was seen to be significant for two reasons: first, the logarithmic spiral is restricted to values of a = 2 √ 2 ; secondly, decreased values of "a" indicate better performance characteristics. For values of a < 2 √ 2 a new trajectory was generated and found to be more efficient than any logarithmic spiral trajectory. / Master of Science