Micro nozzles generating thrusts of the order of 100 mN are used in space stations and satellites for attitude correction.Despite their small thrust output,the repeated firing of these devices lends credence to studies into their effciency.At present,the conventional convergent-divergent nozzle is designed to operate at a specific altitude where the ambient pressure matches with the exhaust pressure.The performance of this nozzle declines at altitudes other than the design altitude.