All-optical damping forces enhanced by metasurfaces for stable relativistic lightsail propulsion

TL;DR

This paper proposes a novel optical damping mechanism enhanced by metasurfaces to stabilize relativistic lightsails during propulsion, potentially improving control and efficiency in interstellar travel.

Contribution

It introduces a new relativistic force that passively dampens transverse motion of lightsails, enhanced by metasurface design, advancing propulsion control methods.

Findings

Relativistic force generalizing Poynting-Robertson effect identified.

Metasurface design enhances damping by two orders of magnitude.

Passive optical damping can improve lightsail stability.

Abstract

Lightsails are a promising spacecraft concept that can reach relativistic speeds via propulsion by laser light, allowing travel to nearby stars within a human lifetime. The success of a lightsail mission requires that any motion in the plane transverse to the propagation direction is bounded and damped for the entire acceleration phase. Here, we demonstrate that a previously unappreciated relativistic force, which generalizes the Poynting-Robertson effect, can passively damp this transverse motion. We show that this purely optical effect can be enhanced by two orders of magnitude compared to plane mirror sails by judicious design of the scattering response. We thus demonstrate that exploiting relativistic effects may be a practical means to control the motion of lightsails.