DETERMINATION OF THE HELIOSPHERIC AXIS ORIENTATION - AN OPPORTUNITY FOR THE CASSINI MISSION TO SATURN

Pick-up ion measurements that could be made during the interplanetary cruise of the Cassini spacecraft to Saturn offer a unique opportunity to determine the orientation of the upwind-downwind axis of the helios phere. The method and results of a feasibility study are presented. Th e study shows that pick-up oxygen is the best candidate for such a mea surement. Model computations are used to predict the actual pick-up ox ygen fluxes which instruments on the Cassini spacecraft would see alon g its trajectory for several currently debated upwind-downwind axis or ientations.