A Laser Ablation Shepherd: Surface Vaporisation Thrust on a 110-Metre Asteroid

This paper computes a laser ablation shepherd that delivers 12,000 W of optical power onto a 110 m asteroid of mass 1,672,583,929 kg. With an ablation energy of 8,000,000 J per kilogram and an ejecta speed of 1,100 m per second, the vaporised mass flow of 0.000825 kg per second produces 0.908 N of recoil thrust and an acceleration of 5.43e-10 m per second squared. Over 2 years the system delivers 34.2 mm per second against a requirement of 22.6 mm per second, a margin ratio of 1.51, a computed separation of 10,591 km, and a total ablated mass of 52,070 kg. This is a computed study of a deflection system for planetary defence, with no targeting or weapon application. It is simulated, not measured.