An emergency door opening apparatus for use on an aerospace vehicle for moving a door of the vehicle from a closed position to an open position. The apparatus includes a fluid cylinder (16) and piston (18) operatively connected to the door and to the vehicle and a supply or gas generating chemicals (24) which, when ignited, are operable to rapidly generate and supply to the fluid cylinder (16) a sufficient amount of gas to move the fluid cylinder (16) and piston (18) to effect opening of the door.