Libration-point orbit missions disposal at the end-of-life through solar radiation pressure

This paper investigates an end-of-life propellant-free disposal strategy for Libration-point orbits that allows the zero-velocity curves to be closed by exploiting solar radiation pressure. The spacecraft is initially disposed into the unstable manifold leaving the Libration-point orbit, before a reflective sun-pointing surface is deployed to enhance the effect of solar radiation pressure. Therefore, the consequent increase in energy prevents the spacecraft's return to Earth. An energetic approach is used to compute the required area for the Hill's curve closure at the pseudo Libration-point SL2, via numerical optimisation. Three European Space Agency missions are selected as test case scenarios: Herschel, SOHO and Gaia. Finally, guidelines for the end-of-life disposal of future Libration-point orbit missions are proposed.