Abstract: A thermal rocket initiator mechanism, including a housing; a primer carriage translatable within the housing; a percussion primer disposed within the primer carriage; and a pair of actuator rods disposed within the housing where one of the pair of actuator rods is coupled to the primer carriage and the other pair of actuator rods is coupled to the housing. The mechanism further includes a rocker arm coupling the pair of actuator rods to one another where the pair of actuator rods are manufactured from a shape memory alloy that changes dimensions upon heating, translating the primer carriage within the housing and correspondingly actuating the percussion primer. The pair of actuator rods includes a long actuator rod and a short actuator rod. The percussion primer is actuated through a ramp structure coupled to the primer carriage and a spring structure coupled to the housing.