Electrostatic Solar Sail: A Propellantless Propulsion Concept for an Interstellar Probe Mission

The electrostatic solar sail (E-sail) is a propellantless propulsion system that is driven by solar wind ions via electrostatic repulsion on multi-kilometer scale tethers. In a full mission design, the tethers are connected to a central body that are spun up to keep tension on the tethers during flight operations in the interplanetary medium. Through a series of NASA Innovative Advanced Concept (NIAC) studies done at Marshall Space Flight Center, the feasibility of a heliopause mission within 10 years was shown, with escape speeds reaching up to 10 AU/year. One key advantage to the E-sail architecture is the 1/r force dependence on the solar distance. This slower drop off of force allows for longer, meaningful acceleration periods out to Saturn (10 AU) and beyond. We aim to discuss conclusions from the NIAC studies in addition to recent findings on tether dynamics and the E-sail force model.