Apollo 9 heat shield plug Lucite display

This is a circular chunk of the heat shield from Apollo 9. Heat shields were manufactured by AVCO Corporation, with integration by NAA (North American Aviation), and are comprised of an extremely lightweight fiberglass honeycomb which is hand filled by air gun with the ablative resin material. The ablative system dissipates heat as the material melts and chars during re-entry, mitigating the 20,000 degree heat experienced by the CSM as it transits through the extreme thermo-dynamic phase of the re-entry corridor.