Apollo Command Module LiOH Filter Assembly, 7.25″ x 7.25″ x 5.25″, bearing an affixed Airesearch label on the side, reading: “Absorber Element CO2, Part 813[…]-1, Serial 29-[…], Order NAS-9-150, NASA 004000029378, Ref Spec ME901-0218-0051." The side is stenciled with red-and-yellow text: “Ground Test Only.” This lithium hydroxide canister was designed to maintain a pure-oxygen environment within the Apollo spacecraft; utilized as part of the Environmental Control Unit (ECU), this assembly used LiOH to absorb carbon dioxide and a filter to trap particulate in the circulating air. A square CO2 scrubber cartridge like this one was the focal point of a key part of the Apollo 13 drama, using duct tape and spare materials to get it operating in the Lunar Module.
