Perspective on Research in Laser Propulsion

A document summarizes the history of research on laser propulsion, starting with the first publication of the laser-propulsion concept in the year 1969, proceeding through studies of laser propulsion within the broader context of advanced propulsion systems in general, and culminating in proof-of-concept experiments and associated studies under the auspices of the Air Force Research Laboratory during the years 1996 through 2007. The document briefly discusses the basic physical principles and engineering concepts of laser propulsion as demonstrated in the proof-of-concept experiments, in which a model rocket denoted a laser lightcraft was lofted to altitudes exceeding 200 ft. (about 61 m). In these experiments, a CO₂-laser beam of pulse energy of 400 J at a repetition rate of 25 Hz was used to vaporize a solid propellant (Delrin® polyoxymethylene) to generate thrust. There is a brief discussion of energy-conversion efficiency in laser propulsion. This is followed by an analysis of the concept of supplementing laser ablation energy, and thereby effectively increasing the energy-conversion efficiency, by incorporating a chemically energetic ingredient (ammonium nitrate) into the Delrin propellant. The document includes an extensive bibliography of research on laser propulsion.