Flown Apollo Command Module Block I Earth Landing Sequence Controller (ELSC) flown on the Apollo 4 mission, measuring 7.25 x 4.5 x 3, bearing a large parts tag affixed to the top, reading: "Item Name: Sequence Controller, NAA Control No. ME 901-0001-0019, Contract No. NAS 9-150, NAA Inspection Serial No. 06398AAF0228, Manufacturer: Northrop Ventura, Mfr Serial No. 49, Mfr Part No. R6920-517." One side is stamped in black text, "S/C 017, Post Recov Item." The unit has four connector ports labeled "J1" through "J4," and a blue "Static Air" port. A plate to the underside reads: “Current Equalizing Module.” Includes the North American Aviation 'Temporary Parts Removal Tag,’ which reads: “Part Number ME-901-0001-0019, Serial/Lot Number C6398AAF0028, S/C 017 PR TPS 008, Removal #225.” In fine condition, with light scattered marks.
Part of the Apollo Command Module's sequential events control system, the ELSC used barometric pressure to detect altitude, utilizing that information to sequentially deploy the Command Module’s drogue, pilot, and main parachutes prior to splashdown. Apollo 4 was the first unmanned test flight of the Saturn V launch vehicle and used the S/C 017 Block I Command Module with modifications to test several important revisions for the Block II design, including a new heat shield and hatch as a result of the Apollo 1 disaster, and full Saturn V configuration. Apollo 4 was a complete success, and the Command Module landed back on Earth about eight nautical miles from the target northwest of Midway Island in the North Pacific Ocean. Flown Apollo 4 items seldom come up for sale.
