Gemini 5

Gemini 5 lifts off on the first manned spaceflight to last over a week, breaking the previous record held by the Soviet crew of Vostok 5; the eight-day flight is crucial in proving that humans could function for the minimum amount of time that a flight to the moon and back again would take. Instead of short-lived batteries, Gemini 5 is the first American spacecraft powered by fuel cells, another important step toward longer flights to the moon. The crew consists of Gordon Cooper and Pete Conrad.