Rocket Girls

Space Shuttle Program SDASM Archives

From the series “Space Shuttle Program” Courtesy SDASM Archives (and tinted pink)


An Excerpt from Rise of the Rocket Girls
by Nathalia Holt

On the evening of July 14, 1965, Mariner sailed by Mars. For twenty-two minutes Helen [Ling] sat in the uncomfortably quiet control room as the data rushed in. Unlike the situation with the Ranger missions, where they could watch the images as they arrived, Mars was too far way. The digital image data came in as strips of paper that had to be processed by IBMs to produce images. The team members couldn’t possibly wait that long. They decided to construct their own picture. They printed out the strips of data on ticker tape and hung them on the wall. Each number in the data corresponded to the brightness of its pixel, short for “picture element.” The colors ranged from light to dark on a scale of twenty-five to fifty. When Dick Grumm, one of the engineers, went to buy chalk, the clerk told him they didn’t have any, but he could use pastels instead.

Using brown, red, and yellow pastels, the engineers made up a key for how the numbers should be colored and got started. It was like a giant paint-by-numbers, and Dick was careful to follow his color key. It wasn’t an easy project: the image was two hundred lines of two hundred pixels per line, an impressive amount of coloring to do. Meanwhile, the public relations folks at JPL were getting nervous. How could they keep the media away from the pretty artwork and make them wait for the official black-and-white images? It turned out they couldn’t. Not only were Helen and the engineers excited by the early glimpse of Mars, but so were the television crews. They filmed the hand-drawn picture and broadcast it to the world; the first-ever image of Mars was radiant in red and brown pastels.

The formal black-and white images were processed over the next few days. They revealed no canals of an alien civilization. Instead the planet was littered with craters reminiscent of the moon’s. It looked like a desert. An editorial in the New York Times declared, “Mars is probably a dead planet.” Yet at JPL hope still remained that a future mission might uncover some remnant of life, perhaps clinging to a crater or bubbling in a warm spring.

In the midst of the Mars excitement, Barbara [Paulson] once again got a call from Helen. They needed her at JPL, and Helen asked, “Wouldn’t you like to come back?” Barbara missed both the lab and the companionship and said she’d be thrilled to return. She was already thinking about potential babysitters. Coming back the second time, she found the computers had grown even more sophisticated. To regain her skills she took programming classes offered at Caltech and sponsored by JPL. The lab’s association with the university was convenient in keeping the computers, both living and wired up, up to date. The women frequently took programming-language courses and also held classes in the lab. Helen was always first in learning the programs, eager to pass on what she had learned to her staff.

Barbara’s friend Kathy Thuleen was back after having kids as well. In a society where only 20 percent of mothers with young children worked outside the home, the women at JPL bonded over their new babies at lunchtime. The talk naturally flowed from the moon to Mars to first words and first steps. While chatting over developmental milestones, they could feel the mood changing in the lab. The engineers were asking them for analyses of increasing difficulty and allowing them greater independence. With their growing responsibilities, the computing section’s work was finding its way into numerous publications, although they were rarely credited in academic journals. Roger Bourke, one of the engineers, felt the injustice. He wondered what he could do to include his colleagues, hindered only by gender. At the same time that they were being denied the full recognition they deserved, it seemed to the young mothers, their work was more important than ever.

Kathy was working closely with Roger, analyzing the mountain of data that Mariner 4 had sent back to Earth. Hovering between the engineering and scientific worlds at JPL, they were uncovering the mysteries of the Martian atmosphere. They discovered that the atmosphere was only one half of 1 percent as dense as Earth’s and that the polar caps that resembled the North and South Poles of Earth were actually frozen carbon dioxide. They determined that, like Venus, Mars lacked a robust magnetic field. However, unlike Venus, which lacks a magnetic field due to its slow rotation, Mars owed its weak magnetic field to its solid core. Without liquid metal that swirls charged particles, like that at the core of Earth, Mars was left without the protection from the solar wind that an atmosphere provides.

The more responsibility Kathy gained in her work — calculating the Martian ionosphere and gravitational effect — the more enthralled she became. Roger recognized these contributions by adding her name to their next paper, which detailed the altitude-control system on board Mariner 5. Kathy gasped when she read “Kathryn L. Thuleen, engineer” on the title page. She had never seen that word, engineer, after her name before.


Analog computer equipment in the old Space Flight Operations control center, 1960 CREDIT: Courtesy NASA/JPL-Caltech)

Analog computer equipment in the old Space Flight Operations control center, 1960 CREDIT: Courtesy NASA/JPL-Caltech

Kathy was at her desk with one of the Mariner calculations when she got a frantic call. It was their babysitter. “Your son’s up in a tree and can’t climb back down,” the sitter cried. “I don’t know what to do.” Kathy didn’t know what to do either. Her husband was only ten minutes away, so perhaps he could leave work. The couple fretted over the phone until they finally thought to call a friend of their son’s. The young boy was able to coax their child down, and all was well. Still, Kathy felt the nagging guild of being a working mom. It was horrible to think she wasn’t there when she was needed.

Luckily, JPL was willing to bend to her and the other mothers’ needs. Kathy and Barbara both got to the lab early in the morning, often startling the deer that wandered through the parking lot looking for breakfast. They conscripted their husbands to drop the kids off with the babysitter. In the early hours they enjoyed the quiet, with the only sounds those of their pencils scratching across paper and the quiet hum of the IBMs in the room next door. In the late afternoon, they rushed home, eager to spend time with their children. The flexibility JPL gave them to shift their hours as needed, coming in early and leaving early, was invaluable. The job was never about sitting at a desk from nine to five. Instead, it was about getting the work done.

While the women were getting the support they needed at work and home, a new JPL project — the Surveyor program — was created to support Project Apollo. The engineers joked about putting a sign on its back, FOLLOW ME, to help keep the astronauts on course. Its goal was to produce a spacecraft that could softly land on the moon instead of crashing into it. If they were going to send men up there, they would have to learn to land them gently.

The Surveyor looked like a long-legged white tripod with two large solar panels at the top. Attached to the body o the ship, just above the tripod legs, were steerable rocket thrusters, the first of their kind. Using radar and an autopilot system, the engines were able to slow the ship down considerably, making a soft landing possible. An antenna was mounted near the panels to transmit images from the two television cameras housed below. Even though by now Ranger 9 had been launched and successfully transmitted live video from the moon’s surface, there was considerable nervousness about broadcasting Surveyor’s delicate landing and photography live. On May 30, 1966, the launch went as planned. Two and a half days later the women watched as the lander approached the moon. The thrusters on board the ship fired as planned, slowing it from nearly 6,000 miles per hour to just 3. The spacecraft softly landed on the lunar surface. At JPL, one of the television network people leaned in to Bill Pickering and said, “Oh, by the way, we’re live all over the world.” Although he always knew the event would be broadcast live, the words shook Pickering; it had to work. An hour later the ship started taking pictures. The mission was flawless.

The next Surveyor mission wouldn’t go as smoothly. During the midcourse correction, which had been carefully plotted by the women, one of the rockets failed to fire. The spacefraft tumbled out of control. It was a frustrating setback, especially sine the first Apollo mission was slated for launch in mere months.

In preparation for the next mission, the Apollo crew had a practice session in January 1967. The cone-shaped Apollo command module sat atop a giant Saturn rocket, divided into two stages to form a launch vehicle powerful enough to lift men into space. The test was a launch simulation, with conditions as close as possible to a real launch: all components assembled and systems up and running. Dressed in their white and silver pace suits, three astronauts — Gus Grissom, Ed White, and Roger Chaffee — crossed the red metal bridge and climbed into the commend module…

Tracking spacecraft position in the control room during the Venus flyby, 1962 CREDIT: Courtesy NASA/JPL-Caltech

Tracking spacecraft position in the control room during the Venus flyby, 1962 CREDIT: Courtesy NASA/JPL-Caltech

… It was 1968, and the women were gearing up for another go at Mars. Mariner 6 and 7 would be the latest craft to fly by the Red Planet. The computers eagerly plotted the spacecraft’s trajectories and programmed the instruments that would probe the planet from space in search of extraterrestrial life. Helen was doing contingency planning, just in case something went wrong with the ship and they had to reroute it. She plotted out new paths using star maps. Instead of the latitude and longitude used to plot location on Earth, Helen used the celestial coordinates, declination and right ascension, to plot positions. She drew the contours on cumbersome eleven-by-seventeen-inch charts, spending long hours on the project even as she hoped that her work would never be used.

Margie [Behrens] was also putting in long hours. She was uniting data from all over the lab to improve signal strength between JPL’s spacecraft and the sound. One of her duties was to send out memos to keep the lab abreast of their progress. It was the first time she had taken direct ownership of a project, and she was proud of seeing her name on the updates sent all around the lab. Because of her involvement in this project, she got the nickname dB counter, since signal strength was measured in decibels, or dB. She laughed at the new moniker; at least it isn’t Bubbles, she thought to herself. She also worked closely with the spacecraft assembly facility and wrote programs to convert the data collected on tape from the spacecraft’s photographic equipment into information the image-processing lab could turn into pictures. Her software was working well. Her marriage, however, was over.

Margie’s friends at JPL had been right: she was too smart for her husband. She had tried her best but couldn’t save her marriage. In the wake of her divorce, Margie felt lonely and isolated. She worried about her four children. Although she felt as though she was the only person in the world splitting with her partner, divorce was actually experiencing a surge of nearly 50 percent in the United States. When California’s Family Law Act passed in 1969, it made no-fault divorces possible in the state. And it wasn’t just in California — across the country, laws allowing couples to separate solely because of “irreconcilable differences” were opening up the option to divorce, especially to women who felt trapped by marriage. As Margie grappled with her decision, she thought, I’ll still have my kids and my job.

Sue Finley, on the other hand, felt nothing. Her mind was slipping away from her. She had been home for six years taking care of her two boys, and while she loved them both dearly, she felt she was going crazy. She tottered along, trying to keep it all together, but she was overwhelmed by feelings of fear and anxiety. She began meeting with a psychologist, who listened to her patiently and then prescribed an unusual therapy. She didn’t need clinical treatment, he said; what she needed was to return to work. “It’ll be better for the children,” he explained. Sue nodded. She was ready to go back. Having a job she was proud of and doing work she was good at made her feel strong and purposeful. She loved being a mother more than anything, but she had missed that feeling.

Friden Calculator Ad courtesy of The Computer History Museum

Friden Calculator Ad—Courtesy The Computer History Museum

In the six years since Sue had left the lab, much had changed. To prepare, she spent months studying manuals, trying to catch up with the new computer-programming languages. FORTRAN 6 had become an industry standard. For the first time, every new IBM could use the same computing language instead of programming being unique to each machine. As she immersed herself in the new technology, Sue could feel the sense of madness drift away. Returning to JPL and her friends, she was thankful to have no feelings of guilt at leaving her children. Her psychologist had told her this was a medical necessity, and it also helped that so many of her colleagues were working mothers. She turned to Helen, Barbara, and the recently returned Merrilyn Gilchrist when she needed support.


While Sue was regaining her sanity and her life in the lab, men were about to walk on the moon. On July 20, 1969, Neil Armstrong and Buzz Aldrin were the first humans to tread on another planetary body. The computers’ fingerprints were all over the historic mission. Their legacy began with the rocket that flew the men up there. It blasted off in stages, a technique made possible by the women’s computations for the world’s first two-stage rocket, JPL’s Bumper WAC. The rocket itself was a successor to the one they had helped advance for the Explorer satellites. A special propellant that needed no ignition fueled the Apollo rocket. The computers had helped develop this novel substance, called hypergolic fuel, when working on liquid propellants for the Corporal. Of course, the Ranger and Surveyor missions they had recently launched were key in determining landing sites for the Apollo missions. And when Neil Armstrong stood on the surface of the moon and said, “That’s one small step for man, one giant leap for mankind,” the voice transmission back to Earth was received because of tracking stations in California and Australia, part of the Deep Space Network that the computers had worked on so faithfully. Apollo 11 was the culmination of a thousand successes, each one building on the next, stretching up into the beyond.

The women watched the first steps on the moon with the same mixture of awe and wonder as millions of other Americans. Yet modestly, they didn’t think about their own handiwork in making it happen. Instead, they were lost in the magic of the moment, glued to the grainy images on their televisions, scarcely believing their own eyes.


The women of the Jet Propulsion Laboratory helped launch the first American satellites, lunar missions and planetary explorations. Those "human computers," as they were called, are seen here in 1953. Courtesy NASA/JPL-Caltech

The women of the Jet Propulsion Laboratory helped launch the first American satellites, lunar missions and planetary explorations. Those “human computers,” as they were called, are seen here in 1953.
Courtesy NASA/JPL-Caltech


Nine days later, it was time to see Mars. Mariner 6 was about to meet the Red Planet, in what JPL called a planetary encounter. Margie waited nervously in the control room. It was the first time they would be able to see live images from another planet, thanks to the high-rate telemetry system she had helped program. Data came streaming in from the spacecraft to the giant antenna at Goldstone as it flew only 2,000 miles from the surface of Mars and more than 40 million miles from Earth. It was late at night, but Margie wasn’t sleepy. As she watched the images coming in real time, excitement coursed through her. Each image revealed new details. The poles, similar to our own North and South Poles, jumped out in white, giving the planet an Earth-like appearance. As the spacecraft got closer, however, the cameras showed a strange topography the scientists called chaos terrain. There were cratered deserts, strange collapsed ridges, and mysterious concentric circles that looked like huge bull’s-eyes.

The information JPL was gaining about Mars was beyond anything they had learned before. While cameras captured the alien terrain, spectrometers and radiometers were analyzing the Martian atmosphere. The new scientific experiments revealed a planet that, with its craters, resembled the moon superficially but otherwise was quite different. The mission quashed any hope of finding complex life on Mars. Temperatures were freezing, and there was very little oxygen in the atmosphere and no vegetation to be seen. Mariner 6 revealed an ancient planet with an extremely thin atmosphere.

It was a blow not only for scientists, some of whom had mistaken a seasonal dust storm for vegetation coming back to life in the Martian spring, but also for popular culture. It flew in the face of what H. G. Wells wrote in The War of the Worlds: “The vegetable kingdom in Mars, instead of having green for a dominant color, is of a vivid blood-red tint.” The fascinating and frightening aliens who populated Mars, famous in both movies such as Invaders form Mars and The Day Mars Invaded Earth and books like Ray Bradbury’s Martian Chronicles, were not a possibility.

Yet the dream of finding another world capable of supporting life was not so easily crushed. There was still a chance that simple life-forms might lurk somewhere on the planet. Just as bacteria live in extreme conditions on Earth, such as in volcanic vents and the ice of Antarctica, as we know they do today, it was possible that similar life could be found on the alien planet. The problem was, JPL would have to get much closer, dig into the planet, and take and analyze samples to find it. This would require a much more complex approach. The need to discover life on Mars, to find companions in the universe, was fast becoming an obsession, one that would persist for decades…


Nathalia Holt is a science writer and the New York Times bestselling author of Rise of the Rocket Girls: The Women Who Propelled Us from Missiles to the Moon to Mars and Cured: The People who Defeated HIV. Her work has appeared in numerous publications including The New York Times, The Los Angeles Times, The Atlantic, Slate, Popular Science, and Time. She has trained at the Ragon Institute of MGH, MIT and Harvard University, the University of Southern California, and Tulane University. She lives with her husband and their two daughters in Boston, MA.







Click here to purchase Rise of the Rocket Girls






*All of the excerpts on my blog are from books that have stayed with me for some reason—because the concept was awe inspiring, changed how I view the world, was beautifully expressed, or all three. ‎I personally curate all of the book excerpts, and I always obtain the author’s final approval before posting their work on my blog.