Ham (Astrochimp)

Ham, on 31 January 1961, became the first chimpanzee sent into space as part of the United States' Mercury-Redstone 2 (MR-2) mission and served as a biological precursor to human spaceflight. Technically known as "No. 65," this primate was used as an active operator during flight, performing tasks in real time. His successful mission directly paved the way for the United States' first human spaceflight, Alan Shepard's mission.^【1】 

Ham’s story began in July 1957 in the untouched rainforests of West Africa, in what was then French-controlled Cameroon. Born a baby chimpanzee in its natural habitat, Ham was captured at the age of two. He was then transported thousands of kilometers away to the Miami Rare Bird Farm in Florida.

By July 1959, the space race between the United States and the Soviet Union had intensified, and NASA required primate testing before human flights. This young chimpanzee, then unnamed and known only as "No. 65" (or occasionally "Chang" in some records), was officially enlisted as a candidate "astrochimpanzee" at the Air Force’s Aerospace Medical Center.^【2】 

Ham’s transformation into an astrochimpanzee was a demanding journey beginning in 1959 at Holloman Air Force Base in New Mexico, combining military discipline with advanced psychological conditioning. Alongside 39 other candidate chimpanzees, Ham underwent a rigorous daily training regimen with zero tolerance for error.^【3】 

In addition to psychological training, Ham was subjected to a series of strenuous physical tests to prepare his body for the physical effects of spaceflight. Like the Mercury Seven astronauts, he was exposed to high G-forces in centrifuges to observe how he would respond under the pressure of launch and re-entry.^【4】 

He also spent extended periods in isolation chambers to adjust his biological clock and metabolism to flight conditions, underwent noise exposure tests, and was conditioned to endure confinement within the cramped "seat-cabin" unit he would occupy during flight.

^{Activity at Launch Pad 5 During S63-20804 (21 January 1961) – RF Controls and Placement of Primate No. 5 into Capsule No. 5 (}Flickr⁾

Ham’s selection for the space program involved a series of elimination stages conducted with military precision and medical rigor. Of the 40 candidate chimpanzees brought to Holloman Air Force Base in New Mexico in 1959, Ham stood out from the beginning due to his intelligence and physical resilience. NASA’s Space Task Group (STG) sought not only a healthy animal but also a calm, composed operator who would not freeze under stress. As training progressed, the candidate pool was reduced first to 18, then to a final group of six—four females and two males—at Cape Canaveral in Florida. These six finalists underwent 29 training sessions in mock Mercury capsules, demonstrating their motor skills.

Until one day before launch, it remained officially undecided which chimpanzee would undertake the historic flight; all six candidates were competing for the title of "first astrochimpanzee." The final decision was made by Dr. James P. Henry of NASA’s Space Task Group and veterinarian Dr. John D. Mosely from Holloman, following final physical examinations and psychomotor tests. Ham not only performed all technical tasks flawlessly but also displayed a noticeably more cheerful, energetic, and engaged demeanor compared to the other candidates. Experts concluded that Ham’s positive mood would provide a critical advantage in coping with the stresses of flight, including extreme G-forces and isolation, and approved him for the mission.^【5】 

A female from the group, one of the most resilient candidates, was selected as backup in case of an emergency. After selection, Ham was placed on a low-fiber diet 19 hours before launch, fitted with biosensors, and kept under continuous medical observation until the moment of his historic flight.^【6】 

The Mercury-Redstone 2 (MR-2) launch on 31 January 1961 at 11:55 a.m. appeared on paper to be a suborbital test flight, but in practice it became a fight for survival for Ham. Approximately four hours before launch, Ham was placed inside his specially pressurized cabin, known as the "seat," and loaded onto the top of the rocket within the Mercury capsule.^【7】 

However, immediately after liftoff, things did not go as planned. A malfunction in the rocket’s fuel regulator caused the engines to produce more thrust than intended, leading to premature fuel depletion. This caused the launch escape system (LES) to activate automatically, propelling Ham’s capsule to an altitude of 157 miles instead of the planned 115 miles. The capsule’s speed reached 5,857 miles per hour, instead of the planned 4,400, subjecting Ham to G-forces of up to 17G—near the absolute limit of what a living organism can endure.^【7】 

Over the approximately 16.5-minute duration of the flight, Ham experienced a total of 6.6 minutes of weightlessness.

^{Chimpanzee "Ham" During Pre-Flight Preparations with One of His Caretakers Before the Mercury-Redstone 2 (MR-2) Test Flight (}Flickr⁾

The technical deviations during the Mercury-Redstone 2 flight made Ham’s return to Earth more dangerous than planned. Due to the rocket’s excessive thrust, Ham splashed down approximately 130 miles (about 210 kilometers) off-target, in the open Atlantic Ocean.^【8】 

The force of impact damaged the capsule’s heat shield, creating two holes in the titanium hull beneath the capsule. The capsule drifted in ocean waves for nearly two hours, during which Ham was exposed to seawater seeping inside and the exhaustion following the flight.

When recovered by the ship’s crew and scientists, Ham was removed from the capsule and shook hands with the ship’s captain. He eagerly accepted an apple offered to him. Shortly after his rescue, when photographers attempted to place him back into the capsule for photos, Ham resisted violently, clearly unwilling to relive the experience.^【9】 

NASA’s decision to use chimpanzees as test subjects before human spaceflight was not arbitrary but based on biological and psychological data. By the late 1950s, scientists were concerned that the microgravity environment of space might severely impair human cognition and motor skills. It was unknown whether a human could withstand high G-forces without fainting, or whether essential functions such as swallowing, breathing, and decision-making could be maintained in weightlessness. Chimpanzees emerged as the closest biological analog to human behavior and physiology.

According to NASA data, chimpanzees had an average reaction time of 0.7 seconds to a stimulus—extremely close to the human average of 0.5 seconds—meaning tests on chimpanzees directly reflected human capabilities.^【10】 

Thus, a chimpanzee aboard the Redstone rocket did not merely test life-support systems; it scientifically demonstrated that physical control levers could be operated and mental focus maintained during launch and weightlessness.

^{Chimpanzee "Ham" (}Flickr⁾

Following his historic flight on 31 January 1961, Ham became a global phenomenon and a symbol of American space achievement. Initial medical examinations aboard the recovery ship USS Donner revealed only mild fatigue and dehydration. However, the calm demeanor he displayed immediately after the flight soon gave way to stress. According to NASA reports, being placed back into the capsule for photographs shortly after recovery caused Ham significant distress, requiring several personnel to calm him down.^【11】 

As NASA’s human spaceflight program accelerated, Ham’s role as an active test subject ended, and in 1963 he was transferred to the Smithsonian National Zoological Park in Washington D.C. For much of the next 17 years, he lived alone in isolation, separated from other chimpanzees, in a single cage.^【12】 

Unlike other primates trained for the space program, Ham was never returned to the harsh laboratory conditions of biomedical research, but his prolonged isolation had a detrimental effect on his social development.

By 1980, he was relocated to the North Carolina Zoological Park to allow him to interact with members of his own species and enjoy a more natural retirement. There, for the first time, Ham was able to socialize with other chimpanzees and spent his final years in peaceful harmony within a natural social hierarchy.

Ham died on 18 January 1983 at approximately 26 years of age from heart and liver failure. After his death, his skeleton was sent to the Armed Forces Institute of Pathology for scientific study, while his other remains were ceremonially buried in front of the International Space Hall of Fame in Alamogordo, New Mexico.^【13】