In the paper a specially designed airspace laser propulsion engine is examined at the non‐conventional laser beam input into the engine nozzle. The experiments are carried out by using of the laboratory stand and pulsed CO2laser. In the experiments, geometrical parameters of the engine and laser pulse characteristics are varied. The technique of the experiments allowed measuring of momentum coupling coefficient Cmwith accuracy of ±10&percent;. The coupling coefficient Cmwas experimentally measured and compared with Cmdetermined theoretically. The dependences of the coupling coefficient on the laser pulse characteristics and geometrical parameters of the engine are also obtained. In the paper the analysis of the flight model of the airspace laser propulsion engine is considered too. © 2004 American Institute of Physics