November 29, 1961: Enos the Orbiting Chimpanzee

Forty-five years ago today, NASA launched Enos the chimpanzee into orbit aboard a Mercury Atlas rocket. Although the Soviet Union had already completed two manned orbital missions, the United States had yet to send a primate on an orbital flight. Enos' predecessor in the Mercury program, a chimp named Ham, had survived a sub-orbital mission aboard a Redstone rocket, but failed to convince NASA administrators that Project Mercury was ready to risk a human astronaut. According to NASA's web site, American experiments with mice and monkeys had carried animals into space as early as 1948. In 1957, the Soviet Union made history by sending a dog named Laika into orbit aboard Sputnik 2.

Enos wasn't the first animal in space, but he may have been the best prepared. Purchased from the Miami Rare Bird Farm in 1960, he completed more than 1250 hours of training at the University of Kentucky and Holloman Air Force Base before being selected for Mercury Atlas 5 just three days before launch. Although MA-5 originally called for three orbits, NASA terminated Enos' flight after just two orbits because of a malfunctioning thruster and other technical difficulties. After traveling over 50,000 miles and spending over three hours in space, the capsule that carried Enos landed safely in the Atlantic Ocean and was recovered just 75 minutes after splashdown. According to first-hand accounts, Enos jumped for joy and shook the hands of his rescuers above the recovery ship.

Mercury Atlas 5 completed the unmanned portion of Project Mercury and paved the way for John Glenn's orbital flight on February 20, 1962. Sadly, less than a year after his own historic mission, Enos died of dysentery caused by shigellosis, which was resistant to antibiotics of the time. According to NASA, Enos' illness was unrelated to his time in space.