Fuel cells combine hydrogen and oxygen to produce electricity, and the only byproduct they create in the process is water. These clean energy sources provide all of the electrical power for the shuttle orbiter and drinking water for the astronauts.
Image right: Space Shuttle Columbia rests on launchpad 39-A at NASA's Kennedy Space Center before the STS-1 mission. Credit: NASA
NASA has been using fuel cells to power spacecraft since the Apollo era, but efficiency and durability were always a challenge. In the 1970s, the NASA Lewis Research Center (now NASA Glenn) performed vital research that improved the performance and efficiency of fuel cells to be used on the space shuttle.
The reactions that produce electricity in a fuel cell take place in the electrodes, or conductors. These electrodes are coated in fine metallic powders called catalysts that speed up the reactions. Before the space shuttle program, engineers used platinum and palladium as catalysts, but these materials degraded and failed to prevent short circuits.
NASA Lewis researchers found that gold mixed with 10 to 20 percent platinum is more efficient and lasts longer. These materials are still used on space shuttle fuel cells today.