English: The original Apollo Sextant from flight AS-202. The sextant determines the Command Module’s position and attitude with relation to stars or landmarks. This data was then supplied to the onboard computer to calibrate the spacecraft’s Inertial Measurement Unit (IMU). This is the first flown Command Module sextant from the Apollo program. AS-202 was the second unmanned test flight of a production Block I Apollo Command/Service Module, launched with the Saturn IB launch vehicle in 1966. This was the first flight of the guidance and navigation system as well as the fuel cell electrical system, to validate their use for the first manned flight. But, the subsequent flight became what is now known as Apollo 1, ending with a tragic fire on the pad and prompting a redesign of the wiring for much of the Block I hardware. Following the mission, this sextant was returned to the manufacturer, Kollsman, for post-flight inspection and evaluation.