Spacecraft, radiator panels for spacecraft, kits for radiator panels, inserts associated with radiator panels, heat pipes associated with radiator panels, external structural reinforcement members associated with radiator panels, and methods of assembling radiator panels are disclosed herein. Some radiator panels include at least one insert that is positioned adjacent to a heat pipe between two spaced-apart face-sheets, with the insert being configured to secure a package to the inside face-sheet opposite of the heat pipe. Some radiator panels include at least one external structural reinforcement member that extends across an external side of the radiator panel.