Apollo CSM Fuel Cell Simulator manufactured by Pratt & Whitney under subcontract for North American Aviation, measuring approximately 44″ tall with a diameter of 22″ and weight of 220 pounds. This example, one of the very first cluster of three used in the ground test simulator, features two manufacturer's plates. The blue Pratt & Whitney Aircraft plaque reads: "Power Supply, Electrical Fuel Cell…Contract No. M5J7XA-450024…Mfr. Part No. T-607600-0J01155, Mfr Serial No. 3." The black North American Aviation plate, affixed below, reads: "Fuel Cell Simulator Part 6…Part N34-850541…Serial 002, Model C34.687." The unit, equipped with many functional components of the flight-ready fuel cells, was used for ground testing of the Apollo CSM interfaces at North American.
The Apollo CSM Block II Fuel Cell Assembly was designed to generate primary power—up to 2,300 watts—and portable water for the Command Module. Primarily constructed of titanium, stainless steel, and nickel, these were configured in a cluster of three units installed in Sector 4 of the Service Module to comprise the CSM power plant. The alkaline fuel cell consumed hydrogen and oxygen to generate electricity in a chemical reaction that also produced drinkable water and heat as byproducts. The electricity powered the spacecraft via a power distribution system, while the water was fed into a storage system in the Command Module to be used for astronaut consumption and for cooling purposes.
When the oxygen tank on Apollo 13 exploded, the loss of oxygen to the fuel cells caused all three to be shut down within 130 minutes leaving the crew to limp home on battery power from the Lunar Module. All flown Apollo fuel cells were left in space as part of the Service Module and only a handful of flight-ready spares remain. Nearly all of those are in museums, including the Smithsonian National Air and Space Museum. This simulator cell, used to verify the function of the Apollo spacecraft prior to its delivery to NASA, represents an essential piece of hardware for manned spaceflight. This is an outstanding artifact representing the technical innovation that went into the Apollo program.
