Each of the engineers with Aaron had a chart of the command module’s dashboards—one of dozens of charts that had been passed out so that the flight controllers could jot down their ideas for different arrangements of the switches, much as a choreographer might block out the steps for an intricate dance. The power-up was certainly intricate, for a switch might have to be left on for one action and then turned off before the next could begin. At nine that morning, Houston had read up to Swigert the basic arrangement of the switches at liftoff, and it was this arrangement that was printed on the charts. The engineers called it the Square One arrangement, and in figuring out different checklists they always returned to the Square One arrangement; otherwise they and the astronauts would have become hopelessly muddled. With the charts, Aaron and his group began to work on what Aaron called the “strawman timeline”—his term for a rough outline of what had to be done (“A strawman is something you can throw rocks at,” he explained), and how best to use the available power, in particular just before splashdown. The strawman timeline included estimates of when different parts of the spacecraft should be powered up, when the service module would be jettisoned and when the lunar module would be, and how much power should be allocated to each operation. When Aaron had finished the initial calculations, he concluded that the command module would have a margin in its batteries after splashdown of just sixteen amp-hours—none too much, for the Recovery Officers were insisting that there must be enough power to inflate the balloons that could right the spacecraft if it landed upside down, and to power a radio beacon signalling its location when it landed. Aaron’s strawman timeline was very rough, and would undergo many changes, but at least it provided a framework that other flight controllers could fit their more detailed checklists into. “Things always overwhelm you until you have a plan,” Aaron said afterward. Even with a plan, there were to be moments when Aaron and the others felt overwhelmed.
At about ten Wednesday morning, Haise, who had been napping in the command module, came into the LM complaining of the cold upstairs. One source of his discomfort, it later turned out, may have been the fact that he was coming down with a kidney infection. It was not the best of mornings. Haise looked mistrustfully at the lithium-hydroxide mailbox that had been built while he was asleep. It added to the clutter in the spacecraft, which was beginning to fill up with polyethylene bags containing the astronauts’ wastes; normally, these would have been vented through a special valve in the command module, but this was now probably frozen, and also such venting could disturb the craft’s fragile trajectory—Reed used to tell astronauts there wasn’t much he didn’t know about them. Yet even though apparently nothing was being vented overboard except the negligible amount of water used to cool the electronic instruments, the craft’s motion continued to be erratic. Haise noticed that the wobble in the thermal roll was worse than it had been the night before when he went to bed. At each revolution, the earth appeared so high in the window that he almost had to get down on the floor to see it, and, conversely, the moon was so low that he had to bob up toward the ceiling to catch a glimpse of it.
In the third-floor Control Room, the FIDO was getting uneasy because the spacecraft’s trajectory had been shifting from its predicted course ever since the PC+2 burn; specifically, the trajectory was shallowing out, and this meant that the angle at which the spacecraft would hit the earth’s atmosphere was becoming more and more acute. If it got too shallow, the spacecraft would miss the narrow downward corridor it had to hit for reëntry and would skip back out into space, in an orbit so elongated that it would return to the vicinity of the earth perhaps in two weeks, perhaps never. Since no one could account for the shallowing, no one could predict whether it would get better or worse. But, whatever was causing it, something had to be done about it before the astronauts missed the corridor—and the earth—altogether. Accordingly, the FIDO and the RETRO decided on a midcourse correction, to be made at about nine-forty-five that night. On the second floor, the Tiger Team engineers, on their own initiative, now began breaking up into small groups and moving into adjacent rooms. There were so many such groups that Reed, the Lead FIDO, had difficulty finding a suitable nook in which to hold a meeting of the Trench. Then, when he finally did find one, Deiterich, the Lead RETRO, whom he was supposed to be meeting with, had dashed off to another meeting. Kranz kept moving from one group to another, for he felt that his main job was to make sure all the engineers were working in the same direction, and that the right matters were taken up by the right people. Another engineer listened in on conversations and jotted down ideas to be integrated later. There were some forty men involved, each with his own particular area of responsibility, so uniformity wasn’t always easy to achieve. Kranz later attributed their success to the intensive drilling they had gone through for months ahead of the flight. Although the flight controllers had never handled either a simulation or a theoretical approximation of anything like the present situation, they had been obliged to solve a great many problems in the course of dozens of simulations, and they had met and divided into groups to do so. During those months of simulations, channels of communication had developed between them, so within seemingly random discussions there was a sort of order, the way there is between the cells in a computer or those of the brain.
On Wednesday afternoon, the flight controllers began making preparations for the midcourse correction to counteract the shallowing. It would be called Midcourse Correction 5, or MCC 5—a designation referring not to any consecutive number of rocket burns but, rather, to one of several points along the trajectory where a midcourse correction was normally made if it was needed. It wasn’t an exact point, and that was fortunate, because the CONTROL had noticed a problem that might require a postponement of the MCC 5 burn. Inside a tank of supercooled helium (used for forcing propellants out of the fuel tanks and into the rocket engine) in the lunar module, pressure was building up to the point where the tank would vent before long. Because this could knock the spacecraft off course again, the CONTROL told the FIDO and the RETRO that it might be best to delay the burn until the venting was over. The trouble was that the CONTROL did not know for sure when the venting would take place. A small disc inside a safety valve would rupture when the pressure reached approximately nine hundred pounds per square inch, but no one could predict the precise instant when this would happen; the best guess seemed to be that it would vent at about ten-forty-five—not long after the time for which the midcourse correction was scheduled. In theory, the venting should not disturb the spacecraft, because the helium would blow out through two apertures facing in opposite directions—an arrangement called a “non-propulsive vent.” The CONTROL told the RETRO that he didn’t have much confidence in the vent’s non-propulsive qualities, so the RETRO agreed to delay the burn for an hour—from nine-forty-five until ten-forty-five, so that the LM would be powered up, and the astronauts would have control—just in case.
At two-thirty in the afternoon, not long after this decision had been made, Haise reported hearing a loud thump in the spacecraft, and he told the CAPCOM, Vance Brand, that he saw through the window a “shower of snowflakes,” which looked as if they had come from the vicinity of the helium tank. The CONTROL, who was almost as startled as Haise, had the telemetry turned on. He reported that the helium still appeared to be in the tank. Haise was not particularly reassured, and neither was the CONTROL, for if the helium hadn’t made the thump and the snowstorm something else had. Haise looked up and saw that the moon had moved to the docking window overhead; this meant that whatever had thumped had caused the spacecraft to wobble some more. The occurrence was uncomfortably reminiscent of the original accident. A couple of hours later, Lovell reported that there had been a master alarm indicating trouble in one of the LM’s batteries. Many of the flight controllers were strongly reminded of the caution light indicating trouble in Main Bus B that had accompanied the initial explosion two days before, and they became extremely quiet. Much later, the flight contro
llers determined that the thump had been made by a malfunction in one of several batteries in the LM. As if history were repeating itself, a supposedly automatic switch had failed and remained on; there had been a short circuit inside the battery; and an electric arc had opened the battery vent valve and sent a shower of liquids into space. This time, however, the damage was much less serious. The TELMU asked Lovell to take the battery off the line for the time being, but it would continue to work after the short circuit even with its vent open.
Then everyone sat back and waited for the helium tank to blow.
David Reed, the Lead FIDO, and Charles Deiterich, the Lead RETRO, got together in the Flight Dynamics Support Room, on the second floor, and began working out the steps leading to splashdown. Deiterich outlined the plan he had thought up the morning after the accident for. jettisoning the service module: The LM would push the entire spacecraft with the service module in front; then the astronauts would detach the service module and reverse directions. Deiterich said it would be as easy as stepping out the door to throw away some garbage and then stepping back inside. With the service module gone, the next major item would be bringing up the command module’s guidance computer and aligning its platform. Kenneth Russell, the Lead GUIDO, who had recently taken this matter up with the Lead GNC at the behest of Kranz, reported that they had been afraid the astronauts once again would be unable to see clearly enough through the windows to distinguish the guide stars. He proposed that in the event they couldn’t make a star check, they base the alignment on the sun and the moon instead of on two stars. Deiterich and Reed didn’t care much for the idea, since they felt that two imprecise checks weren’t much better than one, but they said they could get by with it if they had to.
The next item would be jettisoning the lunar module—normally an easy job, because it was done in lunar orbit, where there was plenty of time, and where the service module could push itself and the command module away from the LM. Now the service module would be gone, and there would be no second chance, because the spacecraft would be hurtling toward the earth. The morning after the accident, Deiterich had also blocked out a way to do the LM jettison, and he recapitulated it now: When the astronauts shut the hatch of the lunar module and also that of the command module, air at cabin pressure would be trapped inside the tunnel between the two; then, when the docking mechanism was released, the pressure would blow the two craft apart, in a sort of cosmic sneeze. Reed and Russell liked the idea. So did Peters, the Lead TELMU, and Loden, the Lead CONTROL—the two officers who were responsible for conserving the LM’s power and propellants—when Deiterich told them about it a little later, since the plan required absolutely no LM maneuver whatever. The LM Systems Engineers were having their own meeting next door—they were extremely interested in knowing what the Trench Engineers had in mind, so that they could budget the electricity, and once they waylaid Deiterich for so long that the Trench meeting came to a halt. Then, by the time he got back, some CM Systems Engineers had made off with Russell—“People were always dragging you off,” he recalled later. “Everyone had a question for everyone else, and before you finished one meeting, you found yourself in another.”
When the Trench group was back together again, Russell brought up another navigational worry. Just before reëntry, the command module—by itself now—would be coming around the dark side of the earth, and that meant that the astronauts wouldn’t be able to check their trajectory with reference to the earth’s horizon, as they normally did. Deiterich had a thought. Instead of doing a horizon check, he said, perhaps the astronauts could do a “moonset check”—a term he had invented—which would involve noting the moment the moon disappeared over the horizon, to see if it vanished at the predicted instant. Russell said he would look into it.
Upstairs in the third-floor Control Room, the console immediately to the left of the CAPCOM’s was occupied by the Chief Flight Surgeon, Dr. Willard R. Hawkins. He and the other Flight Surgeons had not been very busy since the accident, because the biomedical sensors, which normally sent back information on the astronauts’ pulses, their breathing, and their temperatures, had been among the first parts of the telemetry to be turned off after the initial accident. Thereafter, the Flight Surgeons had had to rely for medical data on whatever they could pick up from the astronauts’ conversation. It had occurred to Dr. Hawkins that the astronauts had probably not been drinking enough water—once a common problem among people in ships’ lifeboats—and from time to time he asked the CAPCOM to urge them to take a drink, but he could not be sure whether they actually did. One difference between spacecraft and lifeboats at sea is that astronauts in space don’t feel particularly thirsty, even when they badly need water. Some experts say that in the earth’s gravity blood tends to pool in the lower legs and feet, but in zero gravity this doesn’t happen, so there is more blood around the chest and heart, which the body has to diminish; it does this partly by increasing elimination and partly by decreasing thirst and, hence, the intake of water. Consequently, astronauts can get seriously dehydrated without knowing it. Because the shortage of water aboard the LM was critical—water was essential for cooling the electronic systems—the astronauts had been rationing their own intake severely and saying nothing about it to the ground, a move that complicated Dr. Hawkins’ analysis of their medical problems. However, the doctor had a trick up his sleeve, or thought he had: There was a big tank of water in the service module, and he suggested that the astronauts might drink from that. The difficulty was that to get the water out, the astronauts would have to use some of the sparse supply of entry oxygen from the surge tanks, and they weren’t thirsty enough to do that. One of the Crew Systems Engineers also remembered that the space suits, which the astronauts weren’t wearing, were threaded with tiny capillaries full of water, and all an astronaut would have to do would be to snip off a space-suit toe and drink from it as if it were a wineskin. The astronauts weren’t thirsty enough to try that, either.
As the flight controllers developed their plans, they were continually intercepting some of the several astronauts who remained on hand to help, showing them charts of the dashboards on which they had figured out some new arrangement of switches, and asking their opinion about whether a projected maneuver would actually work. Whenever the flight controllers were far enough along with a plan so that they wanted to have it tried out, they sent one of the dashboard charts, with appropriate notations, down to the astronauts on the ground floor who were running the simulators. Charles Duke, working with the LM simulator, was running through Deiterich’s proposal for jettisoning the service module. Deiterich had stipulated that the spacecraft be brought to a specific attitude first, for otherwise the service module might collide with the rest of the spacecraft farther on; but Duke, wrestling with this change of attitude in the simulator, could never be sure it accurately duplicated the movements of the LM maneuvering the other two modules. Duke moved on to Deiterich’s scheme for jettisoning the lunar module by letting it sort of fizz away, propelled by the pressure in the tunnel. It was complicated by the fact that a lunar module and a command module had never flown alone before. As the LM’s attitude indicators would be off, he had to maneuver to the right attitude for jettison by centering one after another of a series of guide stars in the window, and he found that the series of stars kept bringing the LM’s inertial platform close to gimbal lock. Duke requested a new set of stars, and he complained that acquiring the new attitude would take too much time. Deiterich, however, insisted that it was important, because the LM carried a metal cask full of radioactive fuel, which had to be aimed so that it landed in deep water. The radioactive fuel had been intended for powering scientific instruments left on the moon, and its cask was the only part of the LM that was strong enough to remain intact during the heat of reëntry; it had been designed this way because during a previous mission such a cask, aboard an unmanned satellite, had scattered its radioactive contents through the upper atmosphere, and four years later these could
still be detected around the world. Earlier in the Apollo 13 flight, when it had seemed possible that the spacecraft would come down in the Indian Ocean rather than in the Pacific, the Atomic Energy Commission had sent anxious word that the fuel cask would land uncomfortably close to a populated area of Madagascar. Now Deiterich had assured a representative of the A.E.C. who was present that the controllers would see to it that the cask landed in deep water a couple of hundred miles off the coast of New Zealand.
Thirteen: The Apollo Flight That Failed Page 9