The Mercury 13: The Women Who Reached for the Stars

The Mercury 13

In the early days of the Space Race, as the United States raced to catch up with the Soviet Union’s early victories, the image of an astronaut was forged in the public consciousness. He was a hero, a military man, and a test pilot, exemplified by the seven men selected for Project Mercury. The nation celebrated these pioneers, the Mercury Seven, as the best America had to offer. What remained hidden from the public for decades was that another group of pilots, equally skilled and perhaps even more resilient, was undergoing the exact same grueling tests. This group, composed entirely of women, proved they had what it took to fly in space. They passed the tests, but they would never get their chance. They became known to history as the Mercury 13.

A Private Initiative for Space

The story of the Mercury 13 begins not with an official NASA directive, but with the curiosity of a visionary physician. Dr. William Randolph Lovelace II was the head of the Lovelace Foundation for Medical Education and Research in Albuquerque, New Mexico. As the chairman of NASA’s Special Advisory Committee on Life Sciences, he was instrumental in designing the punishing physical and psychological examinations that the official male astronaut candidates had to endure.

Having developed the testing protocol, Dr. Lovelace began to wonder how women would fare. From a purely physiological standpoint, he theorized that women might even be better suited for spaceflight. They were generally smaller and lighter, meaning less fuel would be required to lift them into orbit. They tended to consume less food, water, and oxygen, which were precious resources on any space mission. Lovelace also noted that women’s reproductive systems were more self-contained and less susceptible to radiation damage, and some data suggested they were less prone to heart attacks than men under stress.

Intrigued by these possibilities, Lovelace decided to initiate a privately funded program to test female pilots. He wasn’t alone in this endeavor. He gained the support of Air Force Brigadier General Don D. Flickinger, a member of his NASA committee. The program also received financial backing from one of the most famous aviators of the era, Jacqueline Cochran. Cochran was a world-renowned pilot who held more speed, distance, and altitude records than any pilot, male or female, of her time. With her support and funding, the Woman in Space Program, as it was unofficially called, began in secret in 1960.

Finding the Right Stuff

The first candidate to be invited was Geraldyn “Jerrie” Cobb. Cobb was an exceptional pilot. She began flying at age 16, earned her commercial pilot’s license at 18, and by her early 20s was flying commercially all over the world. She had logged over 10,000 hours of flight time, more than some of the Mercury Seven astronauts had when they were selected. Lovelace invited her to his clinic, and for several days, she was subjected to the full battery of astronaut tests.

The examinations were invasive, exhausting, and designed to push the human body to its absolute limits. Cobb endured them all. Her results were extraordinary. She placed in the top two percent of all candidates ever tested, including the men. Her stellar performance convinced Lovelace that his theory was correct. Women could not only handle the stresses of spaceflight, but they might even excel. He and Cobb began recruiting more women for the program.

Working with Jacqueline Cochran, they identified dozens of the nation’s most accomplished female pilots. The criteria were strict. Candidates had to be under 40, in perfect health, and have a minimum of 1,000 hours of flight time. This last requirement was slightly different from the men’s, who needed 1,500 hours and a degree from a military jet test pilot school. This difference was a matter of necessity; in the 1960s, women were barred from flying military jets, so they couldn’t possibly meet that specific qualification.

The following table highlights the key differences in the selection criteria for the official NASA program and Lovelace’s private initiative.

Twenty-five women accepted the invitation. One by one, they traveled to Albuquerque, often taking time off from their jobs and paying their own way. The program was so secret that some didn’t even tell their families the true purpose of their trip. They knew only that they were undergoing tests for a special aviation project.

The Gauntlet of Tests

The testing regimen, officially known as Phase I, was identical to what the male astronauts faced. It was a comprehensive, top-to-bottom examination of their physical fitness and endurance. The women were poked, prodded, and measured in every conceivable way. They underwent dozens of X-rays covering their entire skeleton. Their eyesight was tested to the extreme, mapping their field of vision and their ability to perceive depth.

Neurological exams checked their reflexes and brain function. Cardiologists had them run on treadmills to exhaustion while monitoring their heartbeats with electrocardiograms. They swallowed three feet of rubber tubing so doctors could analyze their stomach acid. They were given drinks of radioactive water to measure the total amount of water in their bodies.

One of the most disorienting tests involved having ice-cold water shot into their ears. This procedure, known as caloric testing, induces a powerful sense of vertigo, allowing doctors to evaluate the health of the inner ear, which is vital for balance in a zero-gravity environment. The test was notoriously unpleasant, but the women endured it.

Of the 25 women who began the process, 13 successfully passed Phase I. These thirteen women were: Jerrie Cobb, Wally Funk, Irene Leverton, Myrtle “K” Cagle, Janey Hart, Gene Nora Stumbough (Jessen), Jerri Sloan (Truhill), Rhea Woltman, Sarah Gorelick (Ratley), Bernice “B” Trimble Steadman, Jan Dietrich, Marion Dietrich, and Jean Hixson. Collectively, their test results were on par with, and in some cases better than, those of the Mercury Seven.

With Phase I complete, the successful candidates moved on to Phase II: psychological and isolation testing. For this, some of the women traveled to Oklahoma City. The centerpiece of this phase was the sensory deprivation tank. Each woman was placed in a dark, soundproof tank filled with body-temperature water. The goal was to float motionlessly, deprived of all external stimuli, to see how they would cope with the significant isolation of space. It was a test of mental fortitude. Many of the male astronauts had found the experience difficult and requested to end the test early. The women excelled. Jerrie Cobb remained in the tank for over nine hours. Wally Funk lasted for ten and a half hours, a record for the facility.

The final stage, Phase III, was scheduled to take place at the Naval Air Station Pensacola in Florida. This phase would have involved advanced aeromedical examinations using military equipment. The women would have been subjected to high-G forces in centrifuges and would have flown high-performance jets to simulate the experience of a rocket launch. They were on the verge of proving, unequivocally, that they were ready for space.

An Abrupt End

Just days before Phase III was to begin, telegrams went out to the women. The program was canceled. There would be no tests in Pensacola. The women were stunned and heartbroken. They had quit their jobs, uprooted their lives, and endured incredible physical and mental challenges, only to have their dream snatched away at the last moment.

The cancellation came down to a matter of jurisdiction and politics. The Pensacola facility was operated by the U.S. Navy, which refused to allow the use of its expensive, government-funded equipment for an unofficial, privately-run program. They would only proceed if they received an official request from NASA. Dr. Lovelace and the women hoped NASA would provide that request, but the space agency refused.

NASA’s position was clear: the Woman in Space Program was not a NASA program. The agency was focused on its official astronaut corps, and the selection criteria were firm. President Dwight D. Eisenhower had insisted that all astronauts must be military test pilots. This single requirement, which women were institutionally barred from meeting, became the immovable barrier. The social and political climate of the era simply did not accommodate the idea of female astronauts. The prevailing image of a space explorer was a man, and the bureaucratic machinery of the government was not prepared to challenge that.

A Fight in Washington

Refusing to accept defeat, Jerrie Cobb and Janey Hart, another of the 13 finalists and the wife of a U.S. Senator, decided to take their fight to Washington, D.C. They wrote letters to President John F. Kennedy and Vice President Lyndon B. Johnson, who chaired the Space Council. They lobbied members of Congress, determined to get the program reinstated.

Their efforts led to a special congressional hearing in July 1962 before a subcommittee of the House Committee on Science and Astronautics. The hearing, titled “Qualifications for Astronauts,” was a platform for both sides to make their case. Cobb and Hart testified passionately about their experiences. They presented the data from the Lovelace tests, arguing that it proved women were fit for spaceflight and that it was discriminatory to deny them the opportunity based solely on their gender.

Jacqueline Cochran also testified. While she had funded the initial program, her testimony was surprisingly unhelpful to the women’s cause. She expressed support for the idea of female astronauts in the future but argued that it was important to stick to NASA’s established requirements for now. She felt that creating a separate program for women would be a mistake and that they should wait until they could meet the same qualifications as the men, including the military test pilot requirement.

The most damaging testimony came from two of America’s newest heroes: astronauts John Glenn and Scott Carpenter. Glenn, who had recently become the first American to orbit the Earth, carried immense public authority. He told the committee, “The fact that women are not in this field is a fact of our social order.” He argued that the test pilot background was indispensable and that deviating from this standard would compromise the integrity of the space program. NASA administrator George Low echoed this sentiment, stating that involving women would be a distraction from the primary goal of landing a man on the Moon before the Soviets.

Faced with opposition from NASA, celebrated astronauts, and even one of their own initial supporters, the women’s plea failed. The subcommittee took no action, and the Woman in Space Program was officially dead.

A Soviet First and a Lasting Legacy

Less than a year after the congressional hearing, the world watched as the Soviet Union launched Vostok 6 on June 16, 1963. Aboard was cosmonaut Valentina Tereshkova, who became the first woman to fly in space. Her background starkly contrasted with that of the American women. She was not an experienced pilot; she was a textile factory worker whose main qualification was her expertise as an amateur parachutist. Her selection was a calculated political and propaganda victory for the Soviets, designed to showcase the supposed equality of the sexes in the communist system.

Tereshkova’s flight proved that being a military jet test pilot was not the only pathway to space. It was a bittersweet moment for the women of the Lovelace program. While they were happy to see a woman reach orbit, it was a painful reminder of the opportunity they had been denied.

The thirteen women who passed Dr. Lovelace’s tests never became NASA astronauts. They returned to their lives, many continuing their careers in aviation as flight instructors, commercial pilots, and business owners. For decades, their story was largely forgotten, a footnote in the history of the Space Race. It wasn’t until 1995, when producer James Cross was working on a documentary, that he coined the term “Mercury 13” to give the group a collective name. It was a name that stuck, finally giving them a shared identity.

Though they never reached space themselves, the legacy of the Mercury 13 is undeniable. They challenged the deeply entrenched gender biases of their time and proved that women possessed the physical and mental resilience required for spaceflight. Their struggle for equal opportunity paved the way for future generations. In 1978, NASA finally selected its first group of female astronaut candidates, including Sally Ride, who would become the first American woman in space in 1983.

In the years that followed, some of the Mercury 13 received long-overdue recognition. Jerrie Cobb continued her remarkable life, spending decades as a humanitarian pilot, flying missions deep into the Amazon rainforest. Wally Funk, who never gave up her dream of spaceflight, finally reached the edge of space in 2021 at the age of 82, flying aboard a Blue Origin New Shepard rocket.

Summary

The Mercury 13 were a group of highly skilled female pilots who, in a private program, voluntarily underwent and passed the same rigorous astronaut selection tests as their male counterparts in Project Mercury. Their remarkable performance demonstrated that women were physically and psychologically qualified for spaceflight. The program was abruptly canceled due to a lack of official support from NASA and the U.S. government, which insisted on a military test pilot requirement that was inaccessible to women at the time. Despite a passionate appeal to Congress, their efforts to be included in the nation’s space program were thwarted by the prevailing social and political barriers of the early 1960s. Although they were denied the chance to fly, the story of the Mercury 13 stands as a testament to their skill and determination, and their struggle was a vital, early step in the long journey toward equality in the cockpit and the astronaut corps.