During the 3D scanning project of the Apollo 11 Command Module, museum staff uncovered writing on the interior walls of the module. At some point during the mission, one of the astronauts created a small calendar on a smooth wall below one of the lockers. Each day of the Apollo 11 mission is crossed out except for landing day. The calendar is covered with a plastic sheet held by tape. Museum curators are in the process of trying to determine just when the calendar was drawn.
Smithsonian Institution photo