A high-energy laser system having gyroscopically stabilized optical elements includes an unstable confocal laser resonator having first and second spinning cavity feedback mirrors that resist mechanical wave energy induced spatial dislocations by gyroscopic inertia. One or both of the spinning cavity mirrors are preferably mounted for rotation with the rotor of a gyroscope. The gyroscope is operative as an actuator for selectively tilting the spinning mirror, and as a direction indicator for controlling the pointing direction of other elements with respect to inertial space. The angular rotation of the cavity feedback mirrors generates aerodynamic flows that cool the spinning mirrors by convective heat transport. Every material particle thereof describes an annular path once per revolution that prevents hot-spot formation and extends the useful lifetime.