Abstract: A chemical hybrid propulsion motor can be comparable in performance to a solid motor or liquid fueled engine if it uses cryogenic nitrous oxide as its oxidizer and a pump such as a turbopump to transfer the oxidizer into the motor case. Cryogenic nitrous oxide (at about ?100° F.) has high density which will reduce oxidizer tank volume and weight and this oxidizer combusts at a high oxidizer to fuel (O/F) ratio which minimizes motor case size and weight. The high O/F would also reduce unburnt fuel sliver and hence residual propellant weight. The pump not only transfers the oxidizer into the motor at increased chamber pressure that in turn increases specific impulse, but it also significantly reduces oxidizer tank pressure and weight as compared to a pressure fed motor.