This hatch was the main crew hatch on "Columbia" (CM-107), the Command Module flown on the historic Apollo 11 lunar landing mission. The Apollo hatch had to provide a perfect seal for proper cabin pressurization, thermal protection during re-entry, and water-tight conditions during splashdown and recovery. An example of the "unified hatch" designed following the fatal Apollo 204 fire in January 1967, the Apollo 11 hatch covered the side opening in both the pressurized cabin and the external heat shield that covered the spacecraft.
The hatch was transferred to the Smithsonian Institution by the NASA Johnson Space Center in 1970.
This object is on display in Destination Moon at the National Air and Space Museum in Washington, DC.