After the first successful flight of the chimpanzee Ham in Jan. 31, 1961 US Air Force wanted to further more investigate long-term impact of being in space. They did not want to endanger the life of human astronaut so they prepared another mission with a chimpanzee. This time they planet a longer mission, in which chimp will remain in space for several hours.
US scientist acquired over 60 chimpanzees from Africa in 1950’s and from those they picked only 8 best candidates. Over the years they trained them to live in tight enclosed spaces and to be accustomed with violent conditions of rocket launch (they rode them in centrifuges and rocket propelled sleds). For this mission they picked chimpanzee named Enos who went trough 1263 hours of training. Same as Ham before him, Enos was tasked to actively work with his console in front of his seat. After seeing correct sequence of lights he was trained to press several buttons. Failure to do that would make him receive mild electrical shock to his foot.
On November 29, 1961 Enos was launched to space on board Mercury Atlas 5 rocket. During his flight two major malfunctions happened. First his electronic console started working badly and started shocking him whenever he correctly pressed the buttons. Also one of the rocket’s thrusters stopped working - changing the trajectory and length of his flight. In spite of all those problems Enos strapped in his protective seat and space suit preformed perfectly. After more than 3 hours in space and two orbits around the Earth, Enos made successful landing in the Atlantic Ocean. According to observers he was very glad about returning to Earth, jumping around the deck of the rescue ship and shaking everybody’s hands.
After the flight Enos was examined by the doctors who found that his health was perfect. This long team space exposure convinced scientist to give a green light to longer manned missions to space. February 20, 1962 astronaut John Glenn orbited the Earth three times riding the spacecraft Friendship 7. Enos died six months after his return to Earth from the effects of rare form of dysentery.