"Moon Museum" is a small ceramic wafer that contains sketches from six prominent 1960s artists. It was taken to the moon as part of the Apollo 12 mission. The artists chosen to be on the 3/4" x 1/2" tile were Robert Rauschenbeg, David Norvos, John Chamberlein, Clae Oldenburg, Forrest Myers and Andy Warhol.
The tiny wafer was covertly attached to a leg of the landing module, which was left on the moon after the mission. However, it's impossible to know if the wafer is actually there unless someone goes to look for it. It was Forrest Myers' idea. He tried to get it officially done through NASA, but when they didn't show much interest, he smuggled it on board.
Andy Warhol had a little fun with his drawing. Although officially he drew a stylized version of his initials. However, being the rebel that he was, the sketch can also be mistaken for a penis or a rocket ship.