Mental Floss

Enos the Chimp, First Chimp in Orbit, 54 Years Ago Today

By Chris Higgins

NASA (Public Domain) // Photo ID S61-04540
NASA (Public Domain) // Photo ID S61-04540 / NASA (Public Domain) // Photo ID S61-04540
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Fifty-four years ago today, Enos the Chimp became the first "space chimp" to achieve orbit. He was the second chimp to reach space, after Ham, as part of NASA's Project Mercury. His brief time in space was awful, though you wouldn't know it from this celebratory newsreel, recounting one version of what happened on November 29, 1961:

Keep in mind, the USSR was well ahead of the US at this point in the space race, having put Yuri Gagarin in orbit in April 1961 and Gherman Titov in extended orbit in August 1961.

What Really Happened to Enos

Launched on the Mercury-Atlas 5 mission, Enos achieved orbit, manipulated various controls when lights flashed, and was rewarded for completing tasks with banana pellets. He had been trained to do these tasks (mostly simple logic tests) on Earth, and failing a task meant a shock applied to his feet.

Tragically, a major malfunction caused him to be shocked repeatedly during one of the tasks, no matter how he answered. He endured 76 electric shocks despite performing the task correctly. He just kept trying until the system moved on to the next task.

A further malfunction in the attitude control system caused temperatures to rise around Enos, peaking at 100.5 degrees. NASA decided to abort the mission early, causing Enos to splash down after just two orbits (of the scheduled three). He was then stranded in the floating capsule for 3 hours and 20 minutes before a recovery crew arrived. During this time, he damaged various parts of the capsule (apparently trying to escape) and pulled out his own urinary catheter, while the balloon was inflated. After his recovery, he was happy, according to Kristine Sigsbee's animal astronauts page:

Enos was glad to return to Earth. According to observers, Enos jumped for joy and ran around the deck of the recovery ship enthusiastically shaking the hands of his rescuers. Enos' flight was a full dress rehearsal for the next Mercury launch on February 20, 1962, which would make Lt. Colonel John Glenn the first American to orbit the Earth.

After returning for medical study, Enos was declared healthy. Sadly, he died of antibiotic-resistant dysentery less than a year later, and the location of his remains is unknown. His colleague Ham, the first space chimp, fared considerably better, living until 1983 at the National Zoo in Washington, D.C.