STS-51-F was the 1985 Space Shuttle mission that carried Coca-Cola for the first soft-drink tasting experiment in space.
The mission launched aboard Space Shuttle Challenger on July 29, 1985, and included the Carbonated Beverage Dispenser Evaluation. Coca-Cola and Pepsi each supplied specially designed containers intended to release carbonated drinks in microgravity, where ordinary cans could produce troublesome floating bubbles and foam.
Coca-Cola had proposed the project earlier, but Pepsi pressed for the opportunity to participate too, turning the experiment into a high-profile extension of the “Cola Wars.” Astronauts tested both drinks during STS-51-F, and Coca-Cola later promoted its beverage as the first soft drink tasted in space.
The result was more engineering demonstration than refreshment breakthrough. The drinks were warm and excessively fizzy, and NASA did not add either product to the regular shuttle pantry. Astronauts generally preferred powdered beverages such as Tang, which were easier to prepare and drink in orbit.