This pen is identical to those carried aboard Apollo flights 7, 8, 9, 10, and 11. It is a "space pen" and is able to be used in space at any orientation.The Fisher AG-7 Space Pen was the result of a "million dollar research program" undertaken by the Fisher Pen Company during the 1960s, when NASA needed a pen capable of writing in the gravity-free environment of space.On Earth, ball point pens rely on gravity for ink feed and have a small hole in the top of the ink cartridge through which the ink evaporates slowly. This pen is pressurized with nitrogen which forces the ink out through the tungsten-carbide ball, and the ink was specially formulated so it would not evaporate.Transferred to the National Air and Space Museum from NASA in 1970.