James Benford works out the details around economic rules for scaling power beaming space sails
Arxiv – Starship Sails Propelled by Cost-Optimized Directed Energy by James Benford (25 pages) (H/T – Centauri Dreams) Microwave propelled sails are a new class of spacecraft using photon acceleration. It is the only method of interstellar flight that has no physics issues. Laboratory demonstrations of basic features of beam-driven propulsion, flight, stability (‘beam-riding’), and …