Model and trajectory optimization for an ideal laser-enhanced solar sail

Abstract

A laser-enhanced solar sail is a solar sail that is not solely propelled by solar radiation but additionally by a laser beam that illuminates the sail. This way, the propulsive acceleration of the sail results from the combined action of the solar and the laser radiation pressure. The potential source of the laser beam is a laser satellite that coverts solar or nuclear power into laser power. Such a laser satellite (or many of them) may orbit anywhere in the Solar System and its optimal orbit (or their orbits) for a given mission is still subject to future optimization. This contribution provides the model for an ideal laser-enhanced solar sail and investigates how a laser can enhance its thrusting capability. The term “ideal” means that the solar sail is assumed to be flat and perfectly reflecting and that the laser beam has constant areal power density over the whole sail area. Since a laser beam has a limited divergence, it can provide radiation pressure also at large solar distances and increase the propulsive force into the desired direction. This way, significant reductions in the flight time may be achieved for a variety of missions. This contribution also provides the analysis of some exemplary laser-enhanced solar sailing mission scenarios and presents optimized trajectories without laying too much emphasis on details of the design and operations of the laser source(s).