This fuel cell is a test version of the electric-power generating device used on the two-astronaut Gemini spacecraft during seven missions in 1965-66. It was run for over 1000 hours to demonstrate long-duration functioning. A fuel cell is like a battery, in that it uses a chemical reaction to create an electrical current. Unlike a battery, a fuel cell will continue to generate a current as long as the reactants are supplied. The Gemini fuel cell used liquid oxygen and liquid hydrogen to generate electricity, with water as a byproduct. Oxygen and hydrogen molecules reacted and combined across a "proton exchange membrane," a thin permeable polymer sheet coated with a platinum catalyst.
The Gemini program pioneered the use of fuel cells in space, and a similar technology was subsequently used in the Apollo and Space Shuttle programs. General Electric, the manufacturer, gave this artifact to the Smithsonian.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.