West Computing no longer existed as a physical space, but its alumni pushed their minds and hands in the service of the space program—though in Dorothy Vaughan’s case, it was an indirect effort. The computer minders of the two IBM 7090s being used to track the flight were ensconced at Goddard, and much of the analysis was being done in the Space Task Group’s Mission Planning Analysis Division. The women and men in ACD were as busy as ever, however. Dorothy’s hunch that those who knew how to program the devices wouldn’t want for work was a correct one. Though she wasn’t on the front lines of the programming that was being done for Project Mercury, she did have a hand in the calculations that were used in Project Scout, a solid-fuel rocket that Langley tested at the Wallops Island facility. She had even been making trips up to the test range for work. The Scout rocket had been an important part of laying the groundwork for the manned spaceflight efforts. Engineers used it to take a “dummy” astronaut, weighing as much as a real astronaut, for a four-orbit flight in November 1961.
Other West Computers had a closer view. Miriam Mann worked for Jim Williams, running the numbers for the “rendezvous” research that would allow two vehicles to dock while in space. At the Four-foot SPT, Mary Jackson conducted tests of the Apollo capsule and other components, honing their fitness for the portion of the journey that would take place in the supersonic speed regime. That work would earn her an Apollo Team Achievement Award. Sue Wilder was rolling up her sleeves among the “mad scientists” of Langley’s Magnetoplasmadynamics (MPD) Branch, her work also concerned with the physics of a vehicle reentering the atmosphere.
But because of her close working relationship with the pioneers of the Space Task Group, it was Katherine Johnson who found herself in a position to make the most immediate contribution to the pageant that was about to begin in Florida. The broader implication of her role as a black woman in a still-segregated country, helping to light the fuse that would propel that country to achieve one of its greatest ambitions, was a topic that would occupy her mind for the rest of her life. But with the final countdown in sight, that was a matter for the future. Right now, she was a mathematician, an American citizen whose greatest talents had been recognized, and who was about to offer those talents in the service of her country. Katherine Johnson had always been a great believer in progress, and in February 1962, once again, she became its symbol.
When the phone call came in, forty-three-year-old Katherine was at her desk in Building 1244. She overheard the call with the engineer who picked it up, just as she had overhead the conversation between Dorothy Vaughan and the engineer in 1953, the request that sent her to the Flight Research Division two weeks after she arrived at Langley. She knew she was the “girl” being discussed in the phone conversation. She had seen the astronauts around the building, of course; they had spent many hours in the hangar downstairs, preparing for their missions on a simulation machine called the Procedures Trainer. Some of their briefings with the brainy fellas had happened upstairs, though she was not invited to attend those meetings. That John Glenn didn’t know, or didn’t remember, her name didn’t matter; what did matter, as far as he was concerned—as far as she was concerned—was that she was the right person for the job.
Many years later, Katherine Johnson would say it was just luck that of all the computers being sent to engineering groups, she was the one sent to the Flight Research Division to work with the core of the team staffed on an adventure that hadn’t yet been conceived. But simple luck is the random birthright of the hapless. When seasoned by the subtleties of accident, harmony, favor, wisdom, and inevitability, luck takes on the cast of serendipity. Serendipity happens when a well-trained mind looking for one thing encounters something else: the unexpected. It comes from being in a position to seize opportunity from the happy marriage of time, place, and chance. It was serendipity that called her in the countdown to John Glenn’s flight.
In the final section of the Azimuth Angle research report she completed in 1959, Katherine had marched through the calculations for two different sample orbits, one following an eastward launch and the other a westward, as Glenn was scheduled to fly. Once she had worked out the math for the test scenarios on her calculating machine, substituting the hypothetical numbers for variables in the system of equations, the Mission Planning and Analysis Division within the Space Task Group took her math and programmed it into their IBM 704. Using the same hypothetical numbers, they ran the program on the electronic computer, to the pleasing end that there was “very good agreement” between the IBM’s output and Katherine’s calculations. The work she had done in 1959, double-checking the IBM’s numbers, was a dress rehearsal—a simulation, like the ones John Glenn had been carrying out—for the task that would be laid on her desk on the defining day of her career.
When the Space Task Group upgraded their IBM 704 to the more powerful IBM 7090s, the trajectory equations were programmed into those machines, along with all the other programs required to guide and control the rocket and capsule and compare the vital signs of the flight at every moment to the flight plan programmed into the computer. During the launch phase of the mission, a computer in the Atlas rocket, programmed with the launch coordinates, communicated with Mission Control. If the rocket misfired and was on track to inject the capsule into an incorrect orbit, the flight controllers could decide to abort the mission—a go–no go moment—automatically detaching the capsule from its rocket amd sending it off into the sea in a mangled suborbital trajectory.
Once the capsule climbed through the launch window, separated from the Atlas, and settled into a successful orbit, it established communication links with the ground stations. As the craft flew overhead, it telemetered a torrent of data to the closest tracking station, everything from its speed and altitude to its fuel level and the astronaut’s heart rate. The tracking stations captured the signals with their sixty-four-foot receiving dishes, then relayed this data plus voice communications through a jumble of submarine cables, landlines, and radio waves to the computer center at Goddard. The IBM machines used the inputs they received to make calculations based on the orbit determination programs. Via high-speed data lines—a blazing 1 kilobyte per second—Goddard sent Mission Control real-time information on the spaceship’s current position. There, on the front wall of the room that served as NASA’s nerve center, was a huge lighted map of the world. On the map were inscribed sine wave–shaped tracks, one for each orbit. Hovering over the map was a little cutout of a Mercury capsule, suspended on a wire. As tracking data from the spaceship filtered into Mission Control, the toy capsule moved along the orbit grooves on the map too, a puppet controlled by its master in the sky. The capsule’s signal bounced from one tracking station to the next as the orbit proceeded, like a very fast and expensive game of telephone, constantly communicating its position and status. He’s passing over Nigeria! He’s just about to reach Australia! The crude setup seemed like a miracle: looking at the puppet ship, they could actually “see” the spaceship as it made its rounds.
The Goddard computers also sent the flight controllers their projection of the remainder of the voyage. Where was the capsule compared to where they had calculated it to be at the given time? Was it too high, too low, too fast, too slow? The output included a constantly updated time for retrofire, the moment when the capsule’s rockets had to be fired in order to initiate its descent back to Earth. Retrofiring too soon or too late would bring the unlucky astronaut back down far afield of his navy rescuers.