Laser-Driven Mini-Thrusters

Laser-driven mini-thrusters were studied using Delrin(R) and PVC (Delrin(R) is a registered trademark of DuPont) as propellants. TEA CO2 laser (X = 10.6 p.m) was used as a driving laser. Coupling coefficients were deduced from two independent techniques: force-time curves measured with a piezoelectric sensor and ballistic pendulum. Time-resolved ICCD images of the expanding plasma and combustion products were analyzed in order to determine the main process that generates the thrust. The measurements were also performed in a nitrogen atmosphere in order to test the combustion effects on thrust. A pinhole transmission experiment was performed for the study of the cut-off time when the ablation/air breakdown plasma becomes opaque to the incoming laser pulse.