Flown Apollo 9 CSM overview schematic for the fuel cell/cryogenic system, 22 x 10.5, vertically signed and flight-certified in the left margin in green felt tip, "'Flown on Apollo 9,' Jim McDivitt." The schematic bears an affixed tab to the right side, "FC/Cryo," and diagrams the connections and pathways for Fuel Cell 1, as well as general hardware locations within the Command Module to the upper left. In fine condition. Accompanied by a signed letter of provenance from McDivitt, in part: "This CSM Fuel Cell/Cryogenic schematic was flown on Apollo 9 in March, 1969, aboard the LM-3 moon lander 'Spider,' flying for the first time...This schematic is part of a book of schematics of all CSM and LM systems, which was kept in the lander in case of a system failure, for diagnosis and/or repair. This item is from my personal collection." The fuel cells and cryogenic oxygen tanks are the systems that would later catastrophically fail during Apollo 13, and Fuel Cell 1 in particular was a key point of failure. A superb example of a page from an early flown Apollo manual.
Terms and abbreviations used in our descriptions.