Propulsive Force in an Electric Solar Sail for Outer Planet Missions

An electric solar sail (E-sail) is a recent propellantless propulsion concept for a direct exploration of the solar system. An E-sail consists of an array of bare, conductive tethers at very high positive/negative bias, prone to extract solar-wind momentum by Coulomb deflection of protons. This paper focuses on the positive-bias case with a thick sheath that must be correctly modeled. Ion scattering within the sheath and the resulting thrust are determined. Use of E-sail for outer planet missions would reduce the time of flight; a 2-ton spacecraft might reach Jupiter in less than two years.