An apparatus is provided and includes a reactor core, a boom and a shield assembly supportively interposed between the reactor core and the boom, a heat pipe disposed in thermal communication with the reactor core, a thermoelectric power converter operably coupled to the heat pipe, struts supportively coupled to the heat pipe at opposite ends of the power converter and hinge joints to rotatably couple the struts to the boom, at least one of the hinge joints being spring-loaded.