STS-51-F (also known as Spacelab 2) was the nineteenth flight of NASA's Space Shuttle program, and the eighth flight of Space Shuttle Challenger. It launched from Kennedy Space Center, Florida, on July 29, 1985, and landed just under eight days later on August 6. While STS-51-F's primary payload was the Spacelab 2 laboratory module, the payload which received the most publicity was the Carbonated Beverage Dispenser Evaluation, which was an experiment in which both Coca-Cola and Pepsi tried to make their carbonated drinks available to astronauts.