Apollo: The Race to the Moon (48 page)

Bob Wolf had been pressed into service for this flight only a few weeks before. But he had been working with the lead Booster for several months and felt no special apprehension as the countdown approached zero. Jay Greene was FIDO, Neil Hutchinson was Guido, and Cliff Charlesworth was Flight.

At 7:00:01 in the morning, Cape time, the five F-1 engines on the Saturn S-IC lifted the spacecraft off Pad 39A. All five engines operated nominally at first.

At the 125th second of powered flight on the first stage, the accelerometers in the S-IC began recording lengthwise oscillations in the launch vehicle, producing a chugging motion like a car with bad spark plugs, decelerating and accelerating. This type of vibration was known to rocket scientists as pogo, after the motion of a pogo stick.

Pogo had been encountered in earlier space flights. The Titan that flew the Gemini spacecraft had experienced pogo. The Saturn V on Apollo 4 had shown a mild pogo effect. But never had the pogo been so severe. The vibrations on Apollo 6 were vicious, alternating backward and forward at the rate of five or six cycles per second, producing stresses on the order of plus or minus 10 g’s. The pogo continued for ten seconds, then stopped. The only people who were aware of the pogo in real time were the Marshall engineers in Huntsville, who were watching the detailed data coming in to their own version of the MOCR, the HOSC (Huntsville Operations Support Center). The rest of the S-IC burn was uneventful. In the MOCR, everything looked normal.

The Saturn V staged and the five J-2 engines on the S-II ignited and ran up to full power. Into the fourth minute of the S-II burn everything still looked normal. Then the screens in the Trench began acting up, showing erratic data. This was not unusual. The Trench got its tracking data from several sources, and one of FIDO’s main jobs during a normal launch was to work with a controller who sat downstairs in Building 30’s Communications Center, selecting the clearest channel. As FIDO Jay Greene shifted to a new data source at four and a half minutes into the burn of the S-II, Wolf’s console began showing data that might either reflect a data problem or indicate that engine 2 was faltering. He couldn’t tell which. Seconds later, the console showed that the engine had shut down altogether.

This was bad enough, but then came the shocker: 1.3 seconds later, without any warning, engine 3 shut down. “That was beyond anyone’s imagination,” Wolf said later. The chance of one of the five engines on the S-II stage shutting down was small. The chance that two of these independent systems would shut down simultaneously was infinitesimal.

Jay Greene got his first word “over the airwaves,” as the controllers referred to speech not spoken into headsets. “We got two engines out!” exclaimed an off-duty Booster standing behind Wolf. Wolf was staring at the screen, thinking he had to be getting bad data. Then he looked up at the trajectory plot board. Until then, the course of the Saturn V snaking its way up and across the plot board had overlain the planned trajectory almost exactly. Now, it was visibly deviating, falling under the expected altitude.

Because the likelihood of a dual failure was so remote, the Marshall engineers had not spent much time analyzing how the Saturn V would behave with two engines out. But even the preliminary analyses seemed to indicate conclusively that the vehicle would tumble out of control. They had a euphemism in the space program for such unlikely failures: “a bad day.” You didn’t bother to plan for bad days. By definition, they were the kind of thing that the gods did to you sometimes, and the best thing to do was go home and have a drink and come back the next day to pick up the pieces.

Back in the third row, Charlesworth had not heard the exclamation from the off-duty Booster. Wolf’s voice finally came over the flight director’s loop.

“Flight, Booster,” That was the protocol: Say the name of the person you were calling on the loop, then identify yourself.

“Go.”

“We’ve lost, uh, engine 2 and engine 3.” Wolf’s voice was expressionless.

“You’ve lost the engines?” Charlesworth said, with a perceptible “oh shit” tone in his voice.

“That’s affirmative,” said Wolf.

“Roger. It’s your action.”

In the unmanned Apollo flights, pushing Booster l’s abort switch would directly cause the Saturn V to abort. Booster 1 had the authority to push it on his own initiative. Given the point of the burn at which the shutdown occurred, the mission rules told Wolf to do so. But as he watched the trajectory tracing on the big screen, the deviation wasn’t as bad as the analyses had predicted. There wasn’t any tumbling.

Three seconds of silence passed, as Wolf tried to figure out what was going on.

“Are those adjacent or opposite?” Charlesworth finally asked. The five engines of the S-II were hung from cross beams in the same arrangement as the F-1s in the first stage, with the fifth engine in the middle of the cross beam. If the two engines that had shut down were opposite each other, control would be easier to maintain than if the engines were adjacent. They were adjacent, unfortunately, but Wolf was too busy to answer. Another three seconds of silence. Finally Booster 2 came on the line.

“Flight, Booster 2, we seem to have good control at this time.”

“Roger.”

“Guidance system performing nominally, Flight.” It was Neil Hutchinson chiming in from the Guido console.

“Roger,” said Charlesworth, who by now hadn’t heard from Booster 1 for an eternity. Charlesworth prodded him:

“You sure, Booster?”

The language of the MOCR was one of the most economical in the world, for encapsulated in those three words was a long list of questions. “Are you really sure that the Saturn V is under control, Booster?” Charlesworth was asking. “Are you sure that you shouldn’t hit that abort switch, Booster?” “Are you sure you know what you’re doing, Booster?” All of that and more was in those three words. But from his tone, Charlesworth might have been asking Booster whether he really wanted another cup of coffee.

Down on the front row, Wolf had been going through quiet agonies. The philosophy of the German team at Marshall, instilled in each of its Americans as well, was all in one direction: Be disciplined, be professional, and don’t improvise, especially during an actual flight. The heritage of Marshall was unmanned, automated vehicles. “The Marshall guys were very nervous about these flight controllers,” as one Marshall engineer recalled. “The idea of somebody being able to send a command to the [rocket] was a little bit strange to them.” On the first all-up flight of the Saturn V the preceding November, Booster had sent just such a command, not planned in advance, when there had been a little glitch in the propulsion system of the S-IVB. “He did the right thing,” the Marshall engineer said, “but it was a little bit questionable at the time and some people questioned it.” They questioned it so much, in fact, that Booster 1 for that flight had had a nervous breakdown, and that’s why Bob Wolf had been pressed into service so abruptly.

In this case, the pre-planned, disciplined, by-the-book action was clear-cut. Two adjacent engines out is an abort situation. But, contrary to all the predictions, the thing seemed to be flying. So, in response to Charlesworth’s question—“You sure, Booster?”—Wolf just said: “Data indicates it, Flight.”

And they rode it out. The guidance system on the Saturn worked better than anyone had figured it could under such circumstances. They extended the burn on the remaining three engines for a minute, using the propellants that hadn’t been used by the two silent engines. Then they staged, and that’s when FIDO Jay Greene began to earn his money.

After the two engines had gone out, the vehicle had maintained a pitched-up attitude known as chi-freeze for far longer than it would have under ordinary circumstances. “Well, the S-IVB lit up,” Greene recalled, “and the first thing it said was, ‘Omigod, I’ve got too much altitude.’ And so it pointed its nose straight at the center of the earth.” This battle between the guidance system and the gimbal limits on the engine continued for about eighty seconds, with Greene getting closer and closer to an abort call of his own. When the S-IVB finally gave up trying to get to the altitude it wanted, it had a flight-path angle that was unacceptably low. “So then the little devil said, ‘Well, this is bad, I’ve got to pick up the flight-path angle,’ so it started pitching up, and as it started pitching up it said, ‘Now I’m over speed,’ so it actually went into orbit thrusting backward.”

The plot boards showing where the Saturn had wandered looked as if a drunk had been drawing the trajectory. It was without question the most exciting powered launch anybody in the MOCR had ever witnessed. “A fascinating flight,” Greene said tersely—his very first shift in the MOCR. What was he doing all this time? “Puckering.”

There was more to come. After waiting for two orbits, it came time to relight the S-IVB for a simulation of translunar injection. And it didn’t relight. The S-IVB had now failed, and the controllers used the smaller Service Propulsion System (S.P.S.) engine on the service module as a substitute. They managed to complete most of the maneuvers in the flight plan, and the spacecraft was returned safely to earth, but there remained two sobering, unassailable facts: The pogo in the first stage was so severe that a crew might have been injured, had to abort, or both; and three separate engines had failed.

Later that day, in the early afternoon, Martin Luther King was shot and killed as he stood on the balcony of the Lorraine Motel, and the United States moved from a time of troubles to one of domestic crisis. The rest of the world paid little attention to the Apollo 6 flight one way or the other. Insofar as anyone noticed, it looked like a success—NASA announced, accurately, that all of the mission’s major flight-test objectives had been achieved. Within NASA, Apollo 6 was deeply disquieting.

Slowly, each of Apollo 6’s malfunctions yielded an explanation. The pogo effect had occurred because the natural vibration of the thrust chambers on the F-l engines, approximately 5.5 hertz, was too close to the structural vibration of the vehicle as a whole, which peaked at about 5.25 hertz. A system of shock absorbers was installed to de-tune the engine frequencies, in effect, so that they would never again get into synch with the structural frequencies.

The pogo did not cause the engine failures, however. The S-IVB engine failure and the first of the two failures on the S-II stage had both occurred for the identical reason, ruptures in a six-foot length of stainless-steel fuel line, five-eighths of an inch in diameter, that in each stage carried liquid hydrogen to the starter cup of a J-2 engine. The line had two short vibration-absorbing “bellows” sections in it, and the bellows sections had a wire braid shielding on the outside. When the line was tested on the ground, it worked perfectly, but only because—unbeknownst to the engineers—the liquid hydrogen running through the line caused frost to form on the braided shield, helping to dampen the vibration in the bellows. In the vacuum of space, where there was no moisture to form a protective frost, “those little old bellows just sang like a rattlesnake,” as Jerry Thomson described it (the veteran of the F-l fix was called in on this one too). They quickly fatigued and failed. The bellows section was eliminated in favor of a new, stronger design.

The third of the engines that failed hadn’t really failed at all. Through a manufacturing error at the Michoud Assembly Facility for the S-II, two wires connecting engines 2 and 3 in the S-II stage had been crossed. The shutdown of the sick engine 2 had triggered the shutdown of a healthy engine 3.

Each of these diagnoses and fixes took many weeks—NASA later calculated that 125 engineers and 400 technicians spent 31,000 man-hours on the pogo problem alone. And no matter how exhaustive the tests, the fact remained that while the flight of the first Saturn V had been splendid, the second one had been a cripple that by all rights should have tumbled into the ocean. Had there been men on board Apollo 6, the crew probably would have aborted the mission during the pogo, when they would have been so violently banged around that they couldn’t have operated the spacecraft. If the pogo hadn’t happened, Charlesworth probably would have had the crew abort when the two engines on the second stage shut down. It was all right for Wolf to wait and see what happened with an unmanned vehicle, but it would have been dangerous to do so with a crew on board.

It was in this context that, shortly thereafter, George Low decided that the next launch of the Saturn V should carry men—that it should carry them, in fact, all the way to the moon.

Between flights, the center of gravity at Houston was in Building 2, the nine-story headquarters building at the south end of the complex. The higher the floor, the higher the position. Thus when George Low became manager of ASPO, taking a demotion from his old position as deputy director of the center, his office shifted from the top floor, the ninth, down to the seventh.

Like other senior staff at M.S.C., Low had a suite. It included a large, paneled office with space for a conference table and windows looking out over Clear Lake to the east of M.S.C. In the reception area were his three secretaries, headed by Marilyn Bockting, a secretary with a reputation so stellar that when she died an annual “Marilyn Bockting Award” for the top secretary at M.S.C. was instituted in her honor.

During the week, the three secretaries worked in overlapping shifts, with Judy Wyatt arriving first at about 7:15, a little after Low, and the last of them leaving at 8:00 in the evening, usually before Low himself went home. On Saturdays, Low worked a shorter day, only until five or six. The secretaries traded off Saturdays.

On one spring Saturday in 1968—probably shortly after Apollo 6, though she couldn’t recover the exact date—it was Judy Wyatt’s turn. Frank Borman, the astronaut who was in charge of the tiger team that ASPO had sent out to Downey after the fire, was in Houston that weekend and wanted to report to Low on the status of the redefined Block II command modules that were being produced by North American. Wyatt arranged a half-hour appointment for 9:00. Borman was in there an unusually long time. When he finally emerged, Low called her into the office to take some dictation.