Abstract: The graphite-epoxy heat sink and mounting structure is comprised of a mounting structure constructed of a graphite-epoxy material that is mounted around a heat generating pressure vessel located inside a spacecraft. The mounting structure is a graphite-epoxy structure having three segments. The first and third segments are a graphite-epoxy material with a high thermal conductivity but not necessarily capable of withstanding structural stresses. Between these thermal conductive segments is a segment of graphite-epoxy material capable of withstanding structural stresses to provide a structural integrity for the mounting structure. The thermal energy flows from the pressure vessel, through the thermal conductive layer to a shear panel of the spacecraft that radiates the thermal energy.