Theory of Radiation Pressure on a Diffractive Solar Sail

TL;DR

This paper analyzes the radiation pressure effects on a diffractive solar sail with sawtooth prism elements, showing potential advantages over reflective sails for space propulsion.

Contribution

It provides a theoretical analysis of diffraction-based solar sails, highlighting their efficiency and potential to outperform reflective sails in space propulsion.

Findings

Diffraction efficiency approaches that of a monolithic prism with large grating periods.

Diffractive sails can generate greater transverse radiation pressure than reflective sails.

Modern optical techniques could enable practical diffractive solar sails.

Abstract

Solar sails propelled by radiation pressure enable space missions that cannot be achieved using chemical rockets alone. Significant in-space propulsion for missions such as a solar polar orbiter may be achieved with a sail that deviates sunlight at a large average angular direction. The momentum transfer efficiency of sunlight diffracted from a sun-facing diffractive sail comprised of periodic sawtooth prism elements is examined here. The spectrally averaged efficiency is found to approach that of a monolithic prism when the grating period is much longer than the peak of the solar spectrum. This idealized diffraction analysis predicts a greater transverse radiation pressure force compared to an idealized reflective sail. With modern optical design and fabrication techniques, diffractive solar sails may one day replace reflective sails.