Experimental Study on Pulsed Laser Propulsion Performance of Parabolic thrusters

Air-breathing mode pulsed CO2 laser propulsion performance of parabolic thrusters was studied. Momentum coupling coefficients of different laser pulse energies, laser pulse widths and thruster's geometric structures were measured. In the energy range of 3.5 J to 30 J for our experiment, there is the same specific laser energy of 17.5 J for both thrusters, where the coupling coefficient rises almost linearly with the raise of energy for the energy below 17.5 J, and the coupling coefficient remains almost constant for the energy above 17.5 J. By utilizing a metal needle to lower the threshold of ignition, pulsed CO2 laser propulsion with laser pulse width of 20 mu s, 32 mu s and 40 mu s was carried out, and the coupling coefficient decreases for longer pulse. A kind of accessional nozzle for a parabolic thruster was proposed and the coupling coefficient for different geometric parameters of the nozzle was measured. The coupling coefficient can be raised by 85%, and a coupling coefficient of 413 N/MW was obtained.