Apollo Lunar Module Descent Engine (LMDE) Shutoff Valve, measuring approximately 6 x 8.5 x 6.5, marked "Test Only," with engraved, "2510," "2581," "2554," and "2555," and stamped parts numbers, "P/N 170542 E," "ASSY 170540…S/N 1733, REV L." In fine condition. The Lunar Module Descent Engine was designed to allow the Lunar Module to descend from lunar orbit to a hovering position above the lunar surface and to make a soft landing. Fuel passed through the shutoff valve into the engine's manifold, where it was injected into the combustion chamber to generate thrust. The valves were commanded open and shut in conjunction with the LMDE flow control valve and variable pintle injector for throttle control and engine shutdown.
