1. The heat shields of space vehicles, which melt or wear away during the re-entry into the earth's atmosphere: "The scientisst created a new ablator which could withstand extreme heat."
2. The outer surface of a spacecraft or missile: "Ablation is the erosion of the protective outer surface, or ablator, of a spacecraft or missile resulting from aerodynamic heating caused by travel at hypersonic speeds during re-entry through the atmosphere."

"The ablators on the spacecraft were welded into place using a specialized metal that would withstand great heat."