Spacecraft traveling to other stars can be kept on course using nothing but the pressure of the laser beam pushing them.
March 31, 2026
Original Paper
Asymptotic stability of laser-driven lightsails: Orders of magnitude enhancement by optical dispersion engineering in gratings
arXiv · 2603.26991
The Takeaway
Interstellar travel via laser-pushed 'lightsails' is often dismissed because the sails would wobble out of the beam and get lost. This paper proves that the light itself provides a 'restoring' force that can automatically steer and stabilize the craft for decades-long journeys without any onboard engines.
From the abstract
Lightsails are promising spacecraft that can traverse interstellar distances within decades via radiation-pressure propulsion from high-power lasers. The envisioned missions crucially rely on the sail being confined within the propelling laser beam, requiring restoring and damping mechanisms for both translational and rotational degrees of freedom. Here, we use a two-dimensional rigid model to show that full asymptotic stability of planar nanophotonic sails can be achieved through purely optical