Abstract: A low temperature gas generator 2 comprising a combustion chamber 4, an injector 6 formed with a plurality of recesses each having at least one oxidizer orifice 16, and at least one fuel orifice 10 and a mixing cup plate formed with a plurality of mixing cups 26 each communicating a respective one of said recesses with said combustion chamber 4 and formed with an aspect ratio greater than about 2.0 and less than about 5.0 and a diameter such that the flow velocity of the fuel-oxidizer mixture passing through said mixing cup 26 is in excess of about 150 feet per second.