Recent analyses of spacecraft flyby, Galileo, NEAR, Cassini, and Rosetta spacecraft suggest unusual short-lived changes in their inertia and, likewise, unexplained accelerations. One theory which possibly explains these anomalies assumes the inertial changes are due to Unruh radiation modified by a Hubble-scale Casimir effect. Laboratory scale experiments to demonstrate and verify this theory turn out to be in the form of an asymmetric microwave resonator, also known as, the EmDrive. Various experiments have been performed and are ongoing to verify the validity of the EmDrive using microwaves, but none have been reported in the optical regime. According to the physics of the Unruh radiation and modified inertia due to Hubble-scale Casimir effect theory the net propulsive force generated is a function of the cavity Q and input power. It is proposed in this paper that a high-Q asymmetric, but stable, Fabry-Perot laser resonator should produce very large propulsive forces if the theory is correct. Experiment design to demonstrate the concept is given.