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Apollo 4
The first Saturn V stands on the pad at the Kennedy Space Center in 1967 in preparation for a launch on a test flight known as Apollo 4. (credit: NASA)

“And then on launch day it worked”: Marking the 50th anniversary of the first Saturn V launch (part 1)

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The stages for the first flight of the Saturn V began arriving at the Cape in August of 1966, even before the fire. The third stage, the S-IVB, arrived by air in a special bulbous plane called the Super Guppy. The S-IVB was the only stage that would arrive by air; indeed, the other two stages couldn’t arrive even by ground. They were too big to be transported by either truck or train, so they were barged in—the S-IC from the big plant built especially for Apollo at Michoud, Louisiana, and the S-II from North American’s facility at Seal Beach, California.

Now, Rigell stood beside the S-IC lying on its side, his eyes at the level of the exhaust nozzles of engines 1 and 2. Engines 3 and 4 were two stories above his head.

On September 12, 1966, Ike Rigell, Rocco Petrone’s right-hand man for launch vehicle operations, watched as the S-IC stage of the Saturn V arrived on the barge Poseidon at the Saturn Unloading Facilities on the Banana River. Teams of technicians swarmed over the S-IC, checking to make sure that none of its elaborate wrappings and protections had been damaged during transit. The sole, specialized task of the men Rigell watched was to meet Saturn and Apollo hardware when it arrived at the Cape and see that it was safely transported to the O&C Building (for the spacecraft) or the V.A.B. (for the Saturn).

Only about ten years earlier, Rigell reflected, he and a dozen or so others in Kurt Debus’s launch team had done the whole thing themselves, from loading the rocket up in Huntsville to the launch itself. A couple of them would stay with the Redstone as it snaked its way down through the little country towns of Alabama and Georgia on a long Army flatbed truck. The rest of the group would stow the launch consoles in the trunks of their cars and drive down to the Cape, where they would meet the Redstone, check it out, launch it, and go home. But it had been a different kind of bird in those days. Four men could stand at the base of a Redstone and join hands around it. Now, Rigell stood beside the S-IC lying on its side, his eyes at the level of the exhaust nozzles of engines 1 and 2. Engines 3 and 4 were two stories above his head.

NASA’s official designation for George Mueller’s audacious first-time all-up test was A.S.-501: “5” for the launch vehicle, “01” denoting the number of the flight. Within NASA, the flight was being called simply “five-oh-one.” To the public, the forthcoming flight was known as Apollo 4.


The S-IC was taken first to the Low Bay of the V.A.B., where the components that would become inaccessible when the Saturn was stacked were examined and tested. After the test conductors from Launch Vehicle Operations were satisfied that the first stage was ready, it was moved into the High Bay, where lines were attached from the crane far overhead and the S-IC was slowly lifted into place aboard the mobile launcher. Later the second stage, the S-II, went through the same preliminary checkout in the Low Bay.

On February 23, 1967, they stacked the two stages, an operation that epitomized the extremes of large and small in the Cape’s work. First the S-II, 90 feet long, was lifted by crane 280 feet into the air. Then it was settled down onto the top of the S-IC with a precision measured in millimeters and ounces—the crane operators were trained to lower the hook with such delicacy that the hook could be stopped after it was touching the object below, but before it exerted even the pressure that would crack a raw egg. Once the two stages were aligned, it took a team of engineers and technicians eight hours to join the S-IC and the S-II. The two stages were joined not with welds, but with pins: three 12-inch pins at 120-degree intervals around the periphery of the stage and 216 1.5-inch high-strength fasteners at 6-inch intervals.

This process was repeated for the third stage, the S-IVB. Then came the tests of the assembled launch vehicle’s electrical networks, fire detection, telemetry, tracking, gyroscopes, onboard computers, pumps, engines, transducers, valves, cables, plugs, and hydraulic lines. There were 456 such tests altogether, and they took weeks—just how many weeks depended on how things went. In the case of 501, a new vehicle with birthing pains, the tests took almost four months.

“If I asked a guy how long something would take, he’d tell me ten minutes and it would come up maybe an hour,” recalled Rocco Petrone, who was directing it all. “Everything about the Saturn V was bigger.”

In the O&C Building, the command and service module for the first Saturn V flight, the same spacecraft 017 that Joe Bobik had examined with such indignation after the fire, was undergoing its own exhaustive tests. On June 20, 1967, five months after the fire, spacecraft 017 was gingerly loaded into its specially designed cradle—no more plywood and mattresses—and transported from the O&C Building to the V.A.B., where it was mated to the top of the stack. For the first time, there was now a complete Apollo/Saturn flight article.

The tests and the inspections in the V.A.B. went on for another two months. By now the test conductors were checking to see how the components and subsystems of the launch vehicle, spacecraft, and ground support equipment worked together. Suppose that at the moment of launch one of the umbilical tower’s nine swing arms failed to disconnect. Could the vehicle shut down safely? Answering that question required ten separate tests. Suppose that the hold-down arms failed to release. Another set of tests. Were the hundreds of wires connecting the three stages correctly joined? Weeks of tests. Was each pin among the hundreds in the umbilicals’ electrical interfaces connected to the correct socket within the vehicle? More tests. Slowly, laboriously, the verification seals and the sign-offs accumulated as each of the thousands of items was checked off the list.


On August 26, the crawler carried the 501 stack to Pad 39A. Petrone announced that the Countdown Demonstration Test (C.D.D.T.) for flight 501 would begin on September 20. A week later, he rescheduled it to begin on the 25th. It actually began on the 27th.

For later flights, a C.D.D.T. for a Saturn V lasted four days—sixty hours of actual tests and thirty-six hours of planned holds. Expecting some firsttime delays, Petrone planned for this first C.D.D.T. to take six days. It took seventeen.

As in the old days with the early Atlases and Redstones, nothing worked quite the way it was supposed to. The devices for regulating the flow of propellants and gases into the Saturn’s tanks kept giving them problems because the regulators were designed for such heavy flows that they didn’t know how to handle small ones. The piping had to be modified to trick the regulators into behaving properly. Computers were now in charge of monitoring the propellant loadings, and the software was full of bugs. The Instrument Unit, the brains of the Saturn V, wasn’t keeping the black boxes of electronics as cool as planned. Cable connections on the S-II stage shorted out because of humidity and moisture around the pad. It wasn’t any one thing, but an unending series of delays in almost everything they tried to do. “If I asked a guy how long something would take, he’d tell me ten minutes and it would come up maybe an hour,” recalled Rocco Petrone, who was directing it all. “Everything about the Saturn V was bigger. Getting anywhere was bigger. If you had to pick up a valve, you couldn’t pick it up by hand, you had to get a forklift truck! Everything was one or two dimensions bigger.” Petrone began planning his schedules in terms of what he called the “Saturn V minute,” which he calculated was about five times a normal minute.

It just didn’t seem possible that something that big, that complicated, with so many things that could go wrong, would really work when the time came to light it.

For Ed Fannin, who was by then chief of Mechanical and Propulsion Systems for Launch Vehicle Operations, it began to seem as if the C.D.D.T. had been going on all year. The delays were especially tough on the propellants team. Loading propellants was an intricate operation, with dozens of procedures required to prepare the cryogen lines for LOX and liquid hydrogen, pumps, regulators, and the tankage. All of the valves and settings at the pad had to be set so that the actual loading, the most dangerous part of prelaunch operations, could be conducted by remote control from the Firing Room. Once loading began, there were dozens more procedures, and the process took hours—after all, they were pumping the equivalent of 144 trailer-truck loads of kerosene, liquid oxygen, and liquid hydrogen into the equivalent of a thirty-six-story building. Then, every time the C.D.D.T. hit a snag and had to be stopped, and most of the others on the launch team went off to get some rest, the propellants people had to stay in the Firing Room and off-load, which was even more tedious than loading. For them, the low point of the C.D.D.T. came on October 4, the eighth day, when they got to T–45 minutes, tantalizingly close to the end. Then a computer failed, and they had to off-load 502,000 gallons of kerosene and liquid oxygen from the first stage.

Exasperated, Grady Corn, chief of Fannin’s Propellants Branch, wasn’t even sure that the effort was going to accomplish anything. By his own admission, he was one of the Cape’s “great disbelievers.” Standing at the top of the tower, he would look right straight down along the great length of the rocket to the launcher 363 feet below and know there would be no way in the world for that thing to lift off. He was not joking, and he was not the only person who worked on the Saturn V who felt that way. It just didn’t seem possible that something that big, that complicated, with so many things that could go wrong, would really work when the time came to light it.

Day after day, the C.D.D.T. crept on. The launch team would gain a few hours, encounter a new problem, gather in the woodshed (a little conference room off the Firing Room, so called because of the nature of the encounters people tended to have with Petrone when they were called there), devise a fix, set the clock back, and return to the count.

On October 9, thirteen days after the C.D.D.T. had begun, the count was again getting close, to within T–5 hours, but the launch team was nearing exhaustion. Petrone himself began to lose track of time. He looked down at the consoles in the Firing Room and saw Ernie Reyes, one of the senior engineers for Spacecraft Operations. The spacecraft people were having a comparatively easy time of it—they had already struggled up their own learning curve on the three unmanned Apollo flights launched on Saturn IBs. Petrone marveled at Reyes—he looked so clean! Reyes told Petrone that he’d gone home, slept all night, shaved, and come back to work. Petrone hadn’t noticed that by now he and many of the launch vehicle people were in the twentieth hour of one long shift.

“We just can’t go any further,” Petrone told them, and sent the launch team home for a two-day recess. They came back to work on October 11, whereupon a battery heater in the S-II stage failed. It was about then, Rigell recalled, that the question had to run through your mind: Can we ever get that baby off? Can we ever get all the green lights at one time?


At the Cape, those seventeen days were when “the program came to fruition.” They were the days when Launch Operations came to terms with the Saturn V.

On the afternoon of October 13, the count kept getting closer to T–0. It passed the T–45 mark, their previous best. Then it passed the completion of the power transfer test at T–26. Then it began the chill down process for the thrust chambers in the S-II and S-IVB engines. Then, miraculously, they were at the beginning of the automatic sequence at T–3 minutes 7 seconds. Petrone sat back in Management Row, the raised row of consoles at the back of the Firing Room, and watched the clock get closer to T–0. At this moment, the Saturn V on the pad was a fueled, checked-out, fully operational vehicle, doing everything it would do on launch day except light the igniters. As the clock counted down toward T–14 seconds, the point at which the countdown was to be halted, Petrone turned to Ike Rigell. It was an informal tradition between them at this moment in countdown demonstration tests. “Ike,” Petrone said, “are you sure we got all the igniters out of there?” And Rigell assured Petrone, as he always did, that the igniters were out and this bird wasn’t going to fly away just yet.

The long ordeal had finally come to a close. The men in the Firing Room, too weary to celebrate, drifted out to go home—except for the propellants team, who still had to unload all the propellants. Finally, twenty-eight hours after he had come on shift, Grady Corn announced to Ed Fannin that the propellants were off-loaded. “I think I’ve suffered permanent brain damage,” he added.

“We got through it,” Petrone said, describing the C.D.D.T. as one might recall a battle which one had unexpectedly survived, “and we learned a lot. I mean, we learned.” For Petrone, it was a historic event, whether or not the rest of the world knew about it. At the Cape, those seventeen days were when “the program came to fruition.” They were the days when Launch Operations came to terms with the Saturn V.