Laser Propulsion Activities in Germany

Activities related to laser supported propulsion concentrate on investigations of the fundamental phenomena arising from the interaction of high-power CO_2 laser pulses with a simple bell engine. Breakdown dynamics, plasma, and lightcraft accelerations are carefully measured using optical and laser diagnostics. In a first-order approach the expanding plasma can be described by the point explosion model with counterpressure. Wire guided vertical flight experiments in the laboratory have been undertaken and analyzed. Comparative impulse measurements in ambient air and ablated material are presented for a series of experiments performed either at atmospheric pressure or at reduced pressures down to vacuum. Impulse coupling coefficients, average exhaust velocities,specific impulse, and jet efficiencies are derived from the experimental data. The repetitively-pulsed CO_2 laser device used in all experiments shows a potential of achieving 50 kW average power. Finally, long-term perspectives of laser propulsion will be addressed