Flown ablative hatch plug carried on board the Columbia during the Apollo 11 mission. Plug measures approximately .75″ long and is accompanied by a letter from Dick Williamson, which reads, in part: “I certify this hatch plug was flown on the Apollo 11 first moon landing mission. This hatch plug is one of several that were removed from a panel on the heat shield of the Spacecraft [after recovery].” In fine condition. RR Auction COA.