Apollo: The Race to the Moon (68 page)

The P.T.C. maneuver the night before had been a rough-and-ready approximation. The spacecraft had gotten into more or less the right position, and every ninety minutes Lovell or Haise had fired thrusters to give the spacecraft a turn. Now, however, the LEM engineers and the astronauts in the simulator had worked out a way to get Apollo 13 into a clean, automatic, sustained P.T.C., if the bone-weary Lovell and Haise could carry out the instructions that were relayed up to them.

The first attempt didn’t work. Instead of spinning smoothly on its axis, the spacecraft developed a wobble—a “coning angle.” “And they’re tired,” Kranz recalled of the crew, “I mean, they are really starting to drag at this time.” That, Kranz remembered, thinking of the eminent crowd surrounding the flight director’s console, was when “everybody was sort of glowering.” They wanted to get the crew to sleep, they wanted to get powered down, and “I’m still after passive thermal control.”

They didn’t call him General Savage for nothing. “Okay, we’re gonna go do the thing again,” Kranz announced, and that’s what they did. Fortunately (probably for Kranz as well as the crew), this time the crew did it perfectly.

“So we set up the passive thermal control, and we got powered down and put the crew to sleep, and everybody got happy,” Kranz concluded, “But that was what I’d say was the only significant crisis that erupted.”

It all depended on your point of view.

An issue that had not been stressed during the decision between a slow and a fast burn, but which was as important as any of the others, was that the Control Center badly needed the extra twenty-four hours to prepare for entry. Kraft had asked Kranz about it before he went into the meeting in the viewing room Tuesday morning, and Kranz had been blunt, telling Kraft that there was no way the team could be ready for entry unless they opted for the slow return. This was why Kranz had taken the White Team out of the regular shift rotation to concentrate on the entry. The entry for Apollo 13 would require a completely novel checklist, one that took into account a host of anomalous factors. The batteries in the C.S.M. would have to function for a matter of hours instead of the usual half-hour or forty-five minutes. The LEM was going to execute preparatory maneuvers that were ordinarily done with the S.P.S. engine. The crew would be powering up a command module that had been cold and wet for more than three days. Once the White Team had compiled this checklist, they would have to couch it in such a way that its hundreds of steps could be copied and understood by an exhausted crew.

Because the White Team spent all of Tuesday preparing for the P.C.+2 burn, it wasn’t until Wednesday morning that they began concentrated work on the entry. They were supposed to come to the job fresh—Kranz had insisted that they go home and get some rest after the burn. But some didn’t obey (Kranz himself was a bad example, subsisting on catnaps in the viewing room), and others went home only to end up working on their taxes (Wednesday was April 15). So as the White Team assembled Wednesday morning, they were a disheveled and weary crew, with a little more than two days left before splashdown. Under ordinary circumstances, preparing an entry checklist for a lunar mission was a three-month job.

On that same Wednesday morning, the lithium hydroxide in Aquarius was depleted and the carbon dioxide levels approached the danger point. By that time, however, a solution had been passed up to the crew. Working nonstop since the early hours of the explosion, members of the Crew Systems Division had invented a box that could hold the C.S.M.’s lithium hydroxide canisters and be connected to a hose in the LEM ordinarily used to suck air out of space suits. The box was built out of storage bags, tape, and the stiff plastic covers from the crew’s checklist book. The remaining problem, once the people in Crew Systems had figured out a solution, was explaining to the crew what they had done. Hours had been spent carefully working out verbal instructions for building a contraption that the crew had never seen. (Which would be more accurately understood: Cut a piece of tape “thirty inches long” or “a good arm’s length”?) CapCom read up the instructions, Haise assembled the materials, and Swigert and Lovell managed to put it together before the carbon dioxide level became intolerable. Within a few hours, the level was back to normal.

Down in Room 210, a kind of collaborative choreography was under way. Kranz had assigned Arnie Aldrich to put together the integrated checklist that would jettison the service module, transfer the crew from the Aquarius back into Odyssey, jettison Aquarius, and position Odyssey for the entry. John O’Neill was in charge of translating the checklist into formats that could be used by the crew, making sure that the astronauts in the simulators had verified that they worked. John Aaron was the power manager, responsible for deciding whether the checklist that Aldrich was developing fit within the constraints of electricity and water. Kranz himself refereed arguments, set deadlines, enforced decisions, and kept management informed.

The White Team, now augmented by controllers who had not been working the Apollo 13 mission and calling itself a tiger team in the time-honored aviation tradition, split itself into small working groups that held meetings in nooks and crannies throughout the Control Center. Every three or four hours they would reconvene in Room 210. Aldrich and O’Neill would act as scribes, assembling the new contributions from each group into the right sequence. Then Aaron would analyze whether the procedures were affordable.

Aaron’s job was seemingly impossible. Not only did the entry batteries have to last three times as long as normal, one of the three batteries had been half depleted during the changeover to Aquarius. Aaron worked backwards, making a budget in the manner of a family that doesn’t really have enough money to do something but is going to do it anyway. Then he called together the flight controllers and said, “Here’s the plan, what do you think of that?” When they exploded with protestations and predictions of catastrophe, Aaron and Kelly made slight adjustments—still far short of everyone’s minimal requirements—and went back for another try. “We were in the rationing business,” Aaron said. Then, once they had a scheme that worked, at least on paper, they were “the castle guard for the plan, handing out electrons.”

Some of the decisions that Aaron had to make were draconian. A G.N.C. asked Aaron for permission to turn on the Primary Guidance and Navigation System, PGNS, during the entry. Denied. Then how about the secondary system, consisting of six gyroscopes? Nope, Aaron didn’t think they could afford even that. This left the G.N.C. with the prospect of a tertiary system, which did nothing but measure g forces. If the g-forces buildup varied from the prescribed rate, the astronauts were supposed to adjust the tilt of the C.S.M.—“riding down the g’s,” it was called, a terrifyingly primitive method. Aaron compromised: In addition to the meter registering g’s, G.N.C. could power-up three of the six gyroscopes on the secondary system. That’s the kind of power squeeze they all faced.

Even being ruthless wasn’t enough. After many iterations, the tiger team had completed a checklist that they thought would work. It also left a 16 amp-hours margin, the minimum that the recovery people insisted upon in case the Odyssey landed in the Stable 2, or upside-down, position in the ocean. This stringent budget was taken over to the flight simulators, where Ken Mattingly, the astronaut who would have been on Apollo 13 if he had not been exposed to the measles, tried it out. To Mattingly’s surprise, the hastily prepared checklist worked without a hitch. But instead of landing with a 16-amp-hour surplus, Mattingly ended with a 10-amp-hour deficit.

There was no place to cut. Aaron was already holding most of the systems to budgets that the controllers had originally said they couldn’t possibly live with. Bill Peters, the lead TELMU, came to the rescue. He was now confident that Aquarius would have a small reserve of battery power. The spacecraft’s design provided for power to flow from the C.S.M. to the LEM, to top off the LEM’s batteries. The MER had figured out a way to do it backwards. Aaron could gain 20 amp-hours by using Aquarius to charge Odyssey’s half-depleted Battery A.

The creation of the checklist was a controlled frenzy in which solutions were developed, rejected, and replaced in such rapid-fire sequence that it was difficult at any one moment to be sure how far they had to go. On Thursday, when the Apollo 13 crew inquired about progress, CapCom Joe Kerwin assured them, deadpan, that the checklist would be ready “by Saturday or Sunday at the latest.” Splashdown was Friday.

An Apollo spacecraft returning to earth from the moon did not aim directly at the earth, a passage that no heat shield could survive. Rather, it aimed at the leading edge of the earth so that, as the spacecraft sped by, it would be caught by the earth’s atmosphere and gravity. If the spacecraft was too far from the leading edge, it would continue past the earth into an elongated earth orbit. If it was too close to the leading edge, it would enter the atmosphere at a steep angle and burn up. The area that was neither too high nor too low was about a degree and a half wide—ten miles wide at the point of entry—and was called the entry corridor. From Apollo 8 onward, one of the chief functions of the Trench was to make certain that the returning spacecraft was in the middle of it.

As early as Wednesday morning, lead Retro Deiterich and lead FIDO Reed were puzzled and concerned by Thirteen’s errant trajectory. For unknown reasons, the trajectory was “shallowing,” moving toward the high side of the corridor. If this continued, Lovell and his crew would miss the earth altogether. They called for a midcourse correction. Ordinarily, this would not have been a major event. But to conserve power, the LEM’s guidance system had been turned off after the P.C.+2 burn, and a working guidance system was necessary for a trajectory correction. Instead of turning on the guidance system and trying to get an alignment from scratch, which would still be just as difficult as Stafford had warned in the first hours of the crisis, Reed dusted off an untried procedure.

The method involved taking a sighting on the earth’s terminator—the line dividing the illuminated and darkened portions of the earth. Specifically, the ground told Lovell, he was to align the cross hairs of the A.O.T. so that they were just grazing the “horns” on the crescent earth he was seeing out the window. Lovell remembered that a similar technique had been devised for Apollo 8 as a last-ditch alternative in case of a crisis where everything else had failed. After Apollo 8, the Trench had discarded it, saying to the astronauts, as Lovell recalled their conclusion, “You might as well use prayers if you’re going to try this procedure.” It was with these memories in mind that Lovell heard his instructions. “I hope the guys in the back room who thought this up knew what they were doing,” he told CapCom.

They did. The alignment was accomplished uneventfully and the burn on Wednesday night put Thirteen back into the middle of the corridor.

By Thursday, the temperature in Odyssey was thirty-eight degrees, about that of a refrigerator. Until then, the crew had used Odyssey as the bedroom of a two-room apartment; now they huddled together in the little LEM, which was marginally warmer. But Aquarius, too, was uncomfortable. The walls and windows of the LEM were moist with condensed water. The men were averaging three hours of fretful sleep per day. Also, concerned about having enough water to cool the electronics, all three astronauts had cut their fluid intake to near zero. They deliberately ignored the Surgeon’s instructions to drink—since they didn’t feel that thirsty anyway (one doesn’t, in space), they chose to save water for the equipment. The result was that, without knowing it, all three were becoming dehydrated. Haise had developed a kidney infection and was running a fever.

Fatigue. Cold. Dehydration. As they neared time for entry, the normal performance levels of all three had deteriorated. Now they were going to have to assimilate a hastily written entry checklist, perform a crucial midcourse correction, and then bring the spacecraft home without any of the backup systems that ordinarily provided some margin for error.

On the ground, even as the rest of the tiger team was racing to finish its checklist, Deiterich and Reed were worrying anew over the tracking data. For reasons that continued to baffle them, the trajectory was once again shallowing. Another midcourse correction would be necessary, this one to take place only five hours before the spacecraft hit the earth’s atmosphere.

At 4:00 A.M. on Friday, slightly more than eight hours before the scheduled splashdown and seventy-nine hours after the explosion, Gene Kranz and the White Team took over the consoles in the MOCR. The entry checklist had been given to the crew during an earlier shift. Mattingly, who had practiced it in the simulator, had read it up, a distant voice in Swigert’s ear. Swigert had written down each step in full—he didn’t trust himself to read abbreviations later—and then read them all back to Mattingly for verification. After two hours of this tedious process, Mattingly had switched over to Haise, reading up the somewhat shorter procedures for the LEM.

As Deiterich seated himself at the Retro console, he was still watching a deteriorating trajectory. Earlier, he had thought that the second burn would be a matter of fine-tuning to bring the spacecraft close to the recovery vessels. But as the time for the burn approached, the rate of shallowing kept increasing, and with it the length of the burn that would be required even to keep Thirteen within the corridor. When it came time to execute the burn, the crew’s fatigue became apparent. Guido Ken Russell suddenly noticed on his screen that Lovell had punched P40 into the computer instead of P41. The critical difference was between igniting the large descent engine—not their intention—and igniting the small thrusters. Russell told Kranz: “Should be forty-one, I believe, Flight—not forty,” and the mistake was averted. Then Lovell, one of the most skilled and experienced of the astronauts, mistakenly rolled the spacecraft 18 degrees in the wrong direction. “The crew was deadly tired,” Kranz recalled. Lovell was the most exhausted of all. In addition to carrying the extra duties of command, he had limited his fluid intake even more stringently than the other two, and was the most severely dehydrated. He lost fourteen pounds during the six-day voyage. The roll error was noticed and corrected, and the burn itself went off without a hitch. For Kranz, this period of the flight was one of the most impressive. He thought of it as an extended, intricate duet between the crew and flight controllers.