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Project Mercury: The Incredible Journey of America’s First Astronauts

Written by C. Christian Monson

When most Americans think of the space race, they think of the Apollo program and its triumph over the Soviet Union, putting the first human being on the Moon in 1969. However, people are much less aware of the many legs of the race that led up to that—legs that the US didn’t necessarily win.

One of the best examples of this is Project Mercury, the United States’ first human spaceflight program that sent the first American astronaut into space in 1961. Even though this was a few weeks later than the USSR’s first manned spaceflight, Project Mercury was still an important milestone for American space and aeronautics technology, and it was filled with engineering marvels that amazed the world and inspired global spaceflight programs for decades after.



The Space Race began in October 1957 when the Soviet Union successfully launched Sputnik 1 into orbit making it the first artificial satellite in human history. While Sputnik itself did little more than transmit a radio signal for a few weeks, it caused a panic among the American populace who viewed it as evidence of Soviet technological superiority which could have military implications.

Specifically, it seemed like proof the US was suffering from a “missile gap,” meaning that the USSR had better rocket technology and a much higher number of ballistic missiles. Despite future President John F. Kennedy coining the term in 1958 and using it for his political campaign, no such gap actually existed, and the US had a far larger arsenal of missiles than the USSR. Nevertheless, the fear of the gap spread through the American public, and they demanded the government catch up to the Soviets technologically.

Then, just a month after Sputnik 1, the Soviets launched Sputnik 2 in November 1957. This satellite carried a dog named Laika, a stray from Moscow, making her the first animal to orbit the Earth. It was clear the USSR was planning to send a human being into space, and President Dwight D. Eisenhower ordered the creation of the National Aeronautics and Space Administration, aka NASA.

Taking over the US satellite program from the military, NASA put the first American satellite, Explorer 1, into orbit in February 1958. Now it was time to send a person up too, but which nation would do it first?


In 1958, NASA replaced the United States Air Force’s Man In Space Soonest program with the civilian-run Project Mercury. They had the ultimate goal of putting a human being in orbit who would then, along with the spacecraft, be recovered successfully. This was a much more difficult task than just sending a satellite into space.

For starters, the limit of space was defined at the time by the Federation Aeronautique Internationale’s Karman line, which put it at an altitude of 100 kilometers, or 62 miles. At this point, the atmosphere is thin enough that an aircraft cannot achieve lift without exceeding orbital velocity.

Considering Mount Everest is not even nine kilometers above sea level, this is, well, way up there. And a crewed mission means a much heavier payload than a satellite, meaning a much more powerful rocket than the Juno 1 that had sent Explorer 1 into space, a rocket that could potentially explode, killing the crew.

Additionally, the G-forces created by the rocket’s thrust would be hard on an astronaut’s body, not to mention temperatures upon atmospheric reentry reaching 5,500 degrees Celsius, or 10,000 Fahrenheit, as hot as the surface of the sun. And if that weren’t enough, there is, of course, no air in space, so it would have to be artificially provided for both breathing and pressure.

To overcome these obstacles, NASA created the Space Task Group. In 1959 President Eisenhower granted their Project Mercury “top national priority,” meaning it had first dibs for important materials that would otherwise have been directed to military projects. The US was serious about winning the space race.



The main designer of the Mercury spacecraft was Maxime Feget. He envisioned a craft with a launch escape system that could separate from the launch vehicle in case of emergency, attitude control, a retrorocket system to move the ship out of orbit and induce reentry, and capabilities for landing on water where the astronaut could be retrieved.

Twelve companies bid to build Maxime Feget’s design on a contract for $20 million, or around 186 million in today’s Dollars, with McDonnell Aircraft Corporation winning out. They would build the Mercury spacecraft in St. Louis.

Meanwhile, the production of the Redstone rockets for suborbital missions was granted to Chrysler in Huntsville, Alabama, and the production of the Atlas rockets for full orbital missions to Convair in San Diego. The Atlantic Missile Range at Cape Canaveral Air Force Station in Florida was reserved for launches.

Now the spacecraft and their rockets had to be tested to see if they were safe enough for human beings, but how do you do that? Start sending up monkeys, of course. The first Mercury launch was Little Joe 1 in August 1959, a test of the launch system that failed. However, the first fully successful test was Little Joe 2 that December, and that spacecraft was crewed—by Sam, a rhesus monkey.

Sam, who had “studied” at the School of Aviation Medicine in San Antonio, was a pretty tough astronaut. He flew to an altitude of 88 kilometers, or 55 miles, was weightless for three minutes and experienced 12 Gs, enough to be dangerous for even us much larger human beings. Nevertheless, the USS Borie recovered him alive in the Atlantic Ocean after a total flight time of 11 minutes and six seconds.

Several further tests used primates, but none became as famous as Ham, the single crew member of Mercury-Redstone 2, which launched in January 1961 from Cape Canaveral. Reaching an apogee of 253 kilometers, or 157 miles, Ham became the first great ape in space—before any human being. A suborbital flight, he traveled a total of 679 kilometers, or 422 miles, and landed 16 minutes and 39 seconds after launch in the Atlantic Ocean where he was picked up by the USS Donner.

To facilitate the crewed suborbital flight, the Mercury 5 spacecraft used in Mercury-Redstone 2 had six new systems: environmental control, retrorockets, voice communications, attitude stabilization, abort sensing and a pneumatic landing bag. Ham had to be well trained, too.

From humble beginnings as a wild chimpanzee in Cameroon, Ham, born in 1957, was captured by animal trappers and sold to the Miami Rare Bird Farm before being bought by the US Air Force in 1959 and assigned to Hillman Air Force base in New Mexico along with 39 other “astrochimp” candidates. This number was gradually cut down to 18 and then six, Ham making both cuts. At the time, Ham was still technically known as “No. 65,” the Air Force wanting to avoid any bad press if he didn’t make it back alive, but his trainers often called him “Chop Chop Chang.” He was only named “Ham” for Hamilton Aerospace Medical Center after his return.


Ham did his training under the supervision of neuroscientist Joseph Brady. He had to perform simple mechanical tasks based on visual and electronic stimuli like pulling a lever within five seconds of seeing a blue light. Correctly performing the task earned Ham a banana pellet while failing got him an electroshock to the foot. Ham and the rest of the astrochimps were then moved to Hangar S at Cape Canaveral where they trained on actual Mercury simulators.

By 31 January 1961, Ham was ready to go into space equipped with a pressurized space suit and equipment monitoring his vital signs. There were problems from the get-go. Just a minute after launch, the flight angle was too high. Additionally, when the rocket’s liquid oxygen fuel supply ran out, the abort system registered a drop in engine pressure and fired the launch escape system along with the retro rockets. Altogether this meant Ham was going much faster than expected at 2.3 kilometers per second or over 5,000 miles per hour. This caused him to overshoot the planned landing area by over 200 kilometers or about 130 miles.

Perhaps an even bigger problem was that the cabin lost pressure during the launch due to a loose pin in one of the snorkel valves. Luckily, Ham was in a pressurized spacesuit and unaffected by the malfunction. Nevertheless, he did have to deal with a whopping 14.7 Gs of force and weightlessness for 6.6 minutes, almost two minutes longer than had been planned for.

Still, Ham completed around 50 lever-pushing tasks successfully with similar times to his performance on Earth. Recovered with no injuries beyond a bruised nose, Ham was promptly given an apple as a reward for his brave and monumental service. Afterwards, he retired to the National Zoo in Washington, D.C., where he lived until 1980 when he joined a troop of chimpanzees at the North Carolina Zoo. He passed away in 1983 and was buried at the International Space Hall of Fame in New Mexico.

Ham as well as his fellow astrochimps like Minnie, Ham’s backup for the Mercury-Redstone 2 mission and mother of nine children in the Air Force chimpanzee breeding program, and Enos, the first chimpanzee to orbit the Earth aboard Mercury-Atlas 4, were instrumental in providing scientists with data suggesting how spaceflight would affect human beings mentally and physically. Their successful missions paved the way for the next step of the Mercury Project: human spaceflight.



While the US may have sent the first Great Ape into space, the fact was that Ham wasn’t human. On 12 April 1961, the Soviet Union achieved this milestone first by sending Cosmonaut Yuri Gagarin on a full orbit of the Earth in Vostok 1. Nevertheless, the US was determined to close the gap and put a human being in space.

Previously in 1959, seven men had been chosen as astronauts for the Mercury Project, and they became known as the Mercury 7. NASA had decided to select from Air Force test pilots with extensive military records and a college degree in a STEM field. Additionally, they had to be between 25 and 40 years old and no taller than 5’11” (about 180 centimeters).

From 508 candidates, NASA selected 110 for interviews and then 32 for physical and mental testing. Seven were finally chosen, including John Glenn, who interestingly did not meet the requirements since he didn’t have a college degree. Rather, influential friends along with his personal charisma swayed the selection committee in his favor.

The Mercury 7 went through rigorous training at Cape Canaveral. They had to learn how to maneuver and breathe in a centrifuge subjecting to over 6 Gs of force and simulated a number of emergency simulations like righting out-of-control spacecraft. They practiced weightlessness in a nosediving C-131 military transport plane. They even had to test ocean recovery in pools.

On 5 May 1961 astronaut Alan Shepard finally became the first American in space, completing a suborbital flight aboard Mercury-Redstone 3, also known as Freedom 7, the call-sign it was given by the Mercury 7 astronauts.

Freedom 7 ended up being delayed on the launchpad with Shepard seated in the launch position—on his back—for some three hours. He ended up complaining to mission control that he had to go to the bathroom, but they told him it was impossible because it would take too long to set everything back up. He then threatened to urinate in his spacesuit which he was also told was impossible because it would short out its electric diodes. Irritated, Shepard told them to just shut the power off, which they did, and he relieved himself right there in the Mercury capsule, the urine pooling in the back of his spacesuit.

Urination complications aside, Freedom 7 finally launched successfully at 9:34 AM with 45 million Americans watching on TV. The Redstone rocket subjected Shepard to 6.3 Gs of acceleration before reaching a maximum speed of 2.3 kilometers a second, over 5,000 miles per hour, and an apogee of 187.5 kilometers or 116.5 miles.

Like Ham, Shepard had to perform various tasks as he entered space, only these actually controlled the spacecraft. Specifically, he had to make observations with Mercury’s periscope and manually reorient the capsule for reentry.

After 15 minutes and 22 seconds, Freedom 7 splashed down in the Atlantic Ocean to the northeast of the Bahamas having traveled 486 kilometers or 302 miles. Upon reentry Shepard experienced up to 11.6 Gs of force but was recovered unharmed by the USS Lake Champlain. While the US had not beaten the USSR into space, Freedom 7 was still notable and groundbreaking in that, unlike Yuri Gagarin who parachuted out, Shepard remained in the spacecraft until it reached the surface of the Earth.



It wasn’t just Alan Shepard or even Ham. Project Mercury was the culmination of efforts by thousands of people—and animals.

There were five more crewed flights after Freedom 7, all successful. For example, on 20 February 1962, John Glenn was the first American human to orbit the Earth in Mercury-Atlas 6, aka Friendship 7. Leroy Cooper was the first American to spend over a day in space after launching aboard Mercury-Atlas 9, aka Faith 7. This was the last crewed Mercury mission and last American solo spaceflight.

Additionally, despite carrying just a single astronaut, each Mercury mission required 18,000 personnel to support it, primarily for recovery. In total, the project cost $2.38 billion when adjusted for inflation.

Although it didn’t beat the Soviets to space, the Mercury Program did impress the public and gain popular support for NASA, convince skeptical officials that spaceflight was possible, and grow enthusiasm for the era of space exploration that was to come. The lessons learned went on to inspire other projects like Gemini, Skylab and the Lunar Apollo program. As humanity once again sets its sights on the stars, the Mercury Project shows us that with enough support and motivation, not even the sky is the limit.


“Enos (chimpanzee).” Wikipedia. https://en.wikipedia.org/wiki/Enos_(chimpanzee)

“Ham (chimpanzee).” Wikipedia. https://en.wikipedia.org/wiki/Ham_(chimpanzee)

“How hot is the sun?” Cool Cosmos. https://coolcosmos.ipac.caltech.edu/ask/7-How-hot-is-the-Sun-

“John Glenn.” Wikipedia. https://en.wikipedia.org/wiki/John_Glenn

“Juno I.” Wikipedia. https://en.wikipedia.org/wiki/Juno_I

“Little Joe 2.” Wikipedia. https://en.wikipedia.org/wiki/Little_Joe_2

“Man in Space Soonest.” Wikipedia. https://en.wikipedia.org/wiki/Man_in_Space_Soonest

“Mercury-Redstone 2.” Wikipedia. https://en.wikipedia.org/wiki/Mercury-Redstone_2

“Mount Everest.” Wikipedia. https://en.wikipedia.org/wiki/Mount_Everest

“Orbital spaceflight.” Wikipedia. https://en.wikipedia.org/wiki/Orbital_spaceflight

“Project Mercury.” Wikipedia. https://en.wikipedia.org/wiki/Project_Mercury

“Space Race.” Wikipedia. https://en.wikipedia.org/wiki/Space_Race

“Vostok 1.” Wikipedia. https://en.wikipedia.org/wiki/Vostok_1

“Yuri Gagarin.” Wikipedia. https://en.wikipedia.org/wiki/Yuri_Gagarin

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