Enos’ successful mission paved the way for John Glenn to become the first human to orbit in space in 1962. Enos shot into space on Nov. 29, 1961, in a Mercury Atlas rocket. Technical difficulties forced NASA to abort the flight and Enos landed safely in the Pacific Ocean.
Enos died 11 months later of dysentery at Holloman Air Force Base. NASA said his death had nothing to do with his time in space. Today, NASA and the Russian space agency are still courting controversy by testing the effects of long-term radiation from space travel on squirrel monkeys.