Rare Lunar Module Upper Docking Tunnel Hatch manufactured by Grumman as a developmental or test article circa 1967-1968, measuring 31.5″ x 43.5″ x 8″, with numerous part numbers stenciled in red, beginning with the "LDW280" prefix denoting Lunar Module. The front is marked "LDW280M10515-1" and "LDW280M10515-3," with the hatch handle labeled "Unlock" and "Lock," and the valve handle labeled "Dump Valve Access." The reverse, which would face the interior of the spacecraft, has a black-and-yellow handle labeled, "Pull to Dump." A separate instruction label reads: "Latch Operation: 1. To Lock—Push on handle and rotate CW to stop, 2. To Unlock—Push on handle and rotate CCW to stop." At the top of the hatch is a folding handle marked, "Pull to Release." In fine condition.
The 'dump valve' in the upper hatch was designed to depressurize the LM cabin once the astronauts have donned their Portable Life Support System (PLSS) backpacks and spacesuits prior to opening the lower egress hatch for a moonwalk. The valve could also be used to equalize pressure in the docking tunnel. The hatch would swing inwards into the LM crew quarters, allowing the astronauts to pass through the docking tunnel between the LM and CSM. A fantastic Grumman-manufactured piece of large, mission-critical Lunar Module hardware.
