Orbital dynamics of Sun-facing solar sails under the constraint of constant sail temperature

Abstract

The orbital dynamics of Sun-facing solar sails is investigated considering a constraint of constant sail temperature at the limit of the sail material. Although solar sails can normally be articulated so as to provide thrust with both a transverse and radial component, a Sunfacing attitude with the center of solar pressure behind the center of gravity may be preferred for very large or gossamer sails in order to achieve Sun-facing attitude stability. The proposed Sun-facing solar sails are applicable to space weather and geo-storm warning missions for monitoring the inner solar system environment by in-situ measurement of solar wind plasma and high-energy particle events. Constraining the temperature of the sail to the temperature limit of the sail material allows the innermost circular orbits to be attained thereby maximizing scientific returns. The stability of the heliocentric circular orbit under such radial thrust with the constant temperature constraint is investigated, and the stability conditions are obtained as functions of the radius of circular orbit and the solar sail lightness number accounting for optical/thermal properties.