The present invention relates to a ruggedized enclosure for housing and protecting electronic circuits. The enclosure utilizes a top compartment for housing the circuit and a cooling assembly rigidly coupled to the top compartment. The cooling assembly utilizes a passive radiator to for a rigid truss plate structure. The truss plate structure rigidifies the enclosure helping to protect the enclosure and circuit from destructive shock events and destructive vibration events. The cooling assembly further provides an efficient heat exchange for removing heat from the electronic circuit. A method for protecting an electronic circuit utilizing a rigid truss plate structure is also provided.