This is the right hand hatch from the Gemini VII capsule. The window and trim are missing. Made of titanium, it is covered with shingles of Rene 41 which protected the capsule from the tremendous heat generated during reentry.
Frank Borman and James A. Lovell, Jr. flew the 14-day Gemini VII mission in December 1965, the longest in U.S. history until the Skylab missions in the 1970s. Among other things, they rendezvoused with Gemini VI and conducted more experiments than on any other Gemini flight.
McDonnell Aircraft made the hatch and the National Aeronautics and Space Administration transferred it to the museum in 1972.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.