Flown Portable Life Support System (PLSS) dust plug carried to the lunar surface on board the Apollo 12 lunar module Intrepid. Metal cover measures 1.5? in diameter, with a government inspection stamp on the rim as well as two serial numbers, “ 708365,” and “SV723763.” There are also remnants of another number along the rim. This cap protected a connector interface on the back of the PLSS. This cover would have been removed by astronauts Conrad or Bean prior to their EVA as the crew suited up for their moon walks. Accompanied by a handwritten letter of authenticity from Charles Conrad which reads, “This dust plug seal belonged to LM-6/Intrepid. Therefore, this dust plug seal flew from Earth and landed on the Ocean of Storms, Moon during the period of November 14–24, 1969. Charles Conrad, Jr., CDR, Apollo XII.”
This plug played a critical function on the PLSS during the mission. The PLSS, a component of the A7L space suit, provided breathing gasses, cooling, power, and communications to the astronauts while they were conducting their extra vehicular activities on the lunar surface. The plug protected a connector interface when not in use. The connector was designed for an umbilical which ran between the PLSS itself and a remote control unit which was mounted on the astronaut's chest. The cap was removed prior to EVA as the crew suited up, and would have been left in the lunar module during the moonwalks, making this plug one of the only pieces of a flown PLSS to return to Earth as the bulky 80 plus pound backpacks were jettisoned to the lunar surface by the astronauts prior to lift off from the lunar surface.