Exceptional Apollo CSM sextant presumed flown by consignor on the unmanned AS-202 mission on August 25, 1966, measuring 22 x 11 x 14, bearing a parts tag on the main metal housing, reading: “Apollo G&N System Optical Unit, Part No. 1011000-004, Serial No. KIC 12, Cont. No. NAS 9-497, Designed by MIT Instrumentation Lab, Manufactured by Kollsman Instrument Corp.” Below the tag is the yellow text designating the piece as flight hardware, “Flight 202.” In fine condition, with the main sextant mirror having been re-silvered by the original contractor as it had been heat-damaged in re-entry.
Following the mission, the sextant was returned to Kollsman for post-flight inspection and evaluation. Some conversion from Block I to Block II electronics was completed, and the connectors on the sextant are the Block II versions; the primary differences between the Block I and Block II sextants were internal and involved a different wiring harness and connectors. Kollsman eventually set the unit up for display in their lobby, putting the bellows seals over the optical tubes. Included are the flown ablative optics shield for the telescope optics side and a metal shroud for the sextant side, designed as part of the Block II update but not installed. The sextant was originally purchased from Kollsman by an employee when the company was relocating from Elmhurst, NY, to Merrimack, NH. It was then acquired by the consignor, who had the sextant’s beryllium mirror refinished by the original contractor, Speedring Systems.
AS-202 was the first test flight of the Apollo Command/Service Module with the complete Block I guidance and navigation system in it. The sextant could be used to determine 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). As a critical component of the spacecraft’s navigation system, this precision instrument is an early Apollo artifact of the utmost desirability.
Terms and abbreviations used in our descriptions.