on crew performance during the suited altitude chamber tests. Today we would not dare take this kind of risk—but at this point we were determined to at least catch up with the Russians, if not pass them. CapCom Ed Fendell’s team would give the Go for the EVA on the second orbit at Carnarvon, Australia, and then Ed White would step outside the spacecraft at sunrise over Hawaii. The EVA would be concluded over the Cape. The remote site teams burned the midnight oil to learn enough about an EVA to ask the right questions at the scheduled briefing the next day.
Crew systems engineers briefed the remote site and the control teams on the overall plan and details of the qualification testing. Then I briefed them on the EVA Go NoGo mission rules. Kraft wrapped it up with a brief pep talk. I could feel the confidence grow in the control teams worldwide. Kraft’s ability to use just the right words for the occasion was a rare gift. He was able to convince everyone who worked for him that no matter how steep the odds or how great the risks, we would succeed. Just the sound of his voice on the conference loop would give a young, inexperienced controller at some desolate site the confidence essential for doing his job. All of us who grew up in Flight Control learned how to use our own versions of this confidence-building technique that Kraft taught by example.
An electric shock passed through John Aaron when he learned of his role during the briefing. John, the son of an Oklahoma rancher father and minister mother, had trained in college to be a teacher of physics and mathematics, but on the advice of a friend applied to the space program at graduation. Now, just one year out of Southwest Oklahoma State College, John was Kraft’s Red Team engineer in charge of the Gemini life support, electrical, and communications systems during the first American EVA. To this day John remains the most respected engineer ever to work in Mission Control. He was a superb mentor for younger, less experienced engineers. He would eventually become NASA’s Space Station manager and then the station’s chief engineer.
The maturing technical prowess of the launch team gave us a nearly perfect countdown, with only a minor glitch in lowering the erector that placed the rocket in a vertical position for launch. After a brief hold, the count resumed and Kraft gave the “Go for launch.” Gemini 4 had a large number of objectives. During a four-day mission, we had scheduled the booster rendezvous, the EVA, an array of in-flight maneuvers, and eleven scientific experiments. Each Gemini mission would explore some of the many unknowns of spaceflight and test the new technologies needed for the eventual Moon landing. With less than two years remaining before the first scheduled Apollo manned launch, we needed to race through our adolescence and grow up fast.
All three flight directors were in the MCC for launch. Hodge had run the count from booster fueling through crew wake-up, with Kraft picking up when the crew squeezed into the Gemini spacecraft. Shortly after liftoff, the Titan went through a brief period of POGO, a violent chugging that, if sustained, can cause the rocket to break up. During POGO, we had heard Jim McDivitt’s reports in staccato, then it smoothed out as the Titan raced toward engine cutoff. The new control center was humming, the computers cranking out the Go NoGo recommendations to the flight dynamics team, the controllers smoothly reporting to Kraft.
Five and one-half minutes after liftoff, McDivitt reported booster cut-off. He waited until the booster thrust had decayed and 20 seconds later fired capsule-separation pyrotechnics and then maneuvered away from the booster with the Gemini thrusters. After he turned around, he saw the booster about the length of a football field away. McDivitt braked the Gemini and briefly fired thrusters to close the gap. Minutes later, perplexed, he reported the booster was now moving away and down from the Gemini capsule. In Mission Control, Llewellyn stood up at the RETRO console and started talking over the intercom to Kraft. Gesturing with his hands, like a cab driver in Rome, he was trying to explain what was causing problems for McDivitt.
As the reports came in, and with night rapidly descending, McDivitt again thrust toward the slowly tumbling booster. The range increased to 2,000 feet, then appeared to decrease and then increase again during the night. Coming into daylight, the booster was now over three miles away. McDivitt checked his fuel quantity, conferred with Kraft, and, observing the cutoff limits, terminated the attempt to rendezvous with the booster.
As I sat in the MCC, I was baffled by the problems. Unwittingly, Jim had kicked open the door to the mysteries of orbital mechanics, and I had a new respect for Lunney and Llewellyn, who quickly mastered the mysteries of trajectory control. After the mission we reconstructed McDivitt’s maneuvers. Following separation he was ahead of the booster in orbit and as he thrust toward the booster he was performing a retrograde (slowing down) maneuver. As the spacecraft slowed down it went into a lower orbit. To balance the force of gravity, a spacecraft in a lower orbit (no matter how slightly lower) must travel faster than one in a higher orbit. Thus, by slowing down, McDivitt was descending and going faster, pulling away from the booster’s orbit.
In the trajectory world you have to reset your mental gyroscope; orbital mechanics are counterintuitive, particularly for someone used to flying an aircraft, which follows an entirely different set of rules. I realized then that orbital mechanics was something else I needed to learn a lot more about—particularly if I wanted to be ready for the far more complex orbital maneuvers involved in a rendezvous!
While McDivitt was chasing the booster, Ed White did the best he could to complete the preparation for the EVA, which was scheduled to start over Hawaii at the end of the second orbit. McDivitt looked at the timeline. Since the EVA would expose the Gemini and its occupants to a vacuum, with nothing between them and instant death but the thin fabric of their space suits, he decided to postpone the EVA to the following orbit to make sure all checklist items were completed.
John Aaron, seated with the crew systems engineers at the console, welcomed the delay. It bought them some badly needed time. They had been having trouble keeping in sync with White as he proceeded with his checklist. Using the delay to the third orbit, the astronauts had ticked off the items on the checklist and were now ready for the EVA. Fendell, at Carnarvon, made the call. “Gemini 4, your spacecraft’s looking great. You are Go to depress [depressurize] the spacecraft.”
The oxygen pressure in the spacecraft was gradually reduced from 5.2 pounds per square inch—one third of what we experience on Earth—to three psi. With the pressure suits inflated, White and McDivitt carefully checked out their suit systems, making sure the lock rings and seals held the suit’s air pressure. They then gradually reduced the cockpit pressure to zero. If the suit sprang a leak or they blew off a glove while they were still inside the capsule and the hatch was still closed, they would have had to respond instantly and repressurize. Once they opened the hatch and started the EVA, they faced a different set of problems. With his suit inflated, it was damn near impossible for a Gemini astronaut to get back into his seat and get enough leverage to close the hatch through which he had exited for the EVA. If a major leak occurred in the suit with the hatch open the astronaut wouldn’t survive.
Minutes later, after a brief report from the Hawaii CapCom, John Aaron turned to Kraft, gave a thumbs-up, and quietly said, “We’re Go, Flight.” With the Go from Houston, Ed White emerged over Hawaii to his third sunrise in space, decked out in the suit made by highly skilled seamstresses at David Clark, Inc., in Worcester, Massachusetts.
The world listened mesmerized to the interchange between White, McDivitt, and Gus Grissom, the CapCom at Mission Control during the stateside pass. This was one of those magical moments, like Alan Shepard’s launch and John Glenn’s reentry, that are forever embedded in my memory. Pride, patriotism, and American know-how triumphed that day. We were now neck and neck with the Russians and in the next few minutes would eclipse Leonov’s space walk record. I was happy and proud, almost giddy, but then reminded myself that it was time to get back to business.
There was no real plan for a sequence and evaluation of the extravehicular activity, so White improvised as he went along. He used his thruster gun to maneuver around the Gemini, from the adapter section to the nose, trailed by his umbilical, reporting on what he could see in space and on Earth. He floated and tumbled for twenty minutes, and clearly was in no hurry to return to the spacecraft.
As White passed across Florida, Kraft consulted the timeline and told Grissom it was time to terminate the EVA. Grissom briefly stalled Kraft to give White some more time, then Chris repeated, “I said to get him in!” The final crew comments were vivid. McDivitt: “Come on, let’s get back in here before it gets dark.” White replied, “It’s the saddest moment of my life.” McDivitt, sternly: “Well, you’re going to find it sadder when we have to come down with this whole thing.” White, finally yielding to his commander’s orders, reluctantly responded, “I’m coming.”
