In this paper, the proximity quotient control law, first developed by Petropoulos, is extended to account for both third body effects and solar radiation pressure based on the mission requirements for a hypothetical NEO deflection mission to the asteroid Apophis using a solar sublimation deflection technique. The perturbing effect of solar radiation pressure becomes relevant when dealing with large optics in space. Equations for the disturbing acceleration are derived for the perturbations, then analytically incorporated into the equations determining the rate-of-change in time of the orbital elements, and tested using a
Earth-asteroid transfer. Another specific variant of the control law is developed for the orbital maintenance
of the spacecraft formation in the vicinity of the NEO
