The White Team’s work on the reëntry checklist continued without letup into Wednesday night. One of the busiest flight controllers was John Aaron, who said later that the time he spent on the checklist was an unbroken blur of discussions, simulations, and revisions—a single continuous process. Whenever one of the other engineers wanted to turn an instrument on in the spacecraft he had to find out whether Aaron would give him the power. Accordingly, Gary Coen, one of the GNCs, who were responsible for maintaining the navigation and propulsion systems that would keep the command module in the narrow reëntry corridor, sought out Aaron to see how much power he could pry loose. The command module had three separate navigation systems, and clearly they couldn’t all be powered up. Coen wanted to use its Primary Guidance and Navigation System, or PGNS, which included the guidance platform and computer and was the most reliable, but Aaron wouldn’t hear of it; the PGNS used too much power. Coen then asked about the secondary system, which included a set of six small gyroscopes that did the same job as a guidance platform but not as reliably. The secondary system did use less power, but Aaron was not sure he had enough power even for it. The third alternative was a simple meter that indicated gravity forces, or Gs. The astronauts would know they were within the reëntry corridor if they were receiving the right number of Gs, which would increase at a known rate all the way down. If the command module began receiving too many or too few Gs, they could bring it back on course by manually adjusting its tilt so that the command module’s flat bottom bit more or less deeply into the atmosphere. When the command module was receiving Gs at the same rate once more, the astronauts would know they were back in the corridor again. The simplicity of this expedient was a link with the days when explorers had no computers or inertial platforms to guide them, but, simplicity or no, none of the flight controllers were happy at the thought that they might actually have to use this method, which they called “riding down the Gs.” Coen didn’t want to try it unless he had to. About the only concession he could get from Aaron was that, in addition to the gravity meter, half of the secondary system—three of the six little gyros—could be powered up early enough to be warm at the time of reëntry. That was not much of a guarantee, but Coen let the matter go for the time being. He had to hit Aaron for electricity for another purpose, to turn on some heaters which would warm the command module’s thruster jets in case propellant had frozen inside their nozzles; if the ice wasn’t melted, the thrusters might have difficulty firing while the astronauts were trying to keep the command module within the corridor, regardless of which navigation system was used. Aaron said no. Coen then offered a suggestion that would require less power, that the thrusters be deiced by test firing them. They consulted Reed, Russell, and Deiterich, who objected at once that the test firing could knock the spacecraft off its trajectory. At times the spacecraft seemed so hopelessly complex that no flight controller could propose an action without several others vetoing it. Even Loden, the Lead Control, who overheard the discussion, complained that it might bring the LM’s guidance platform close to gimbal lock. Almost anything, however, was better than a plan Loden and some of the LM systems engineers were hatching, which was to be used in the event that the command module couldn’t be powered up at all, so there wouldn’t be even a gravity meter, let alone thruster jets. These engineers had figured that if worse came to worst, the LM could place the command module at the right attitude for reëntry and then, before it was itself jettisoned, set the command module spinning at about four revolutions a minute—fast enough to stabilize it as it plunged through the atmosphere.
A little before ten Wednesday evening, the astronauts began getting ready for MCC 5, the mid-course correction to counteract the shallowing; it would be a small burn, designed to shave seven feet per second off the spacecraft’s speed. The spacecraft had crossed over from the moon’s gravity into the earth’s gravity that morning, and had since been slowly picking up speed as it began the long drop into the Pacific. It was still travelling at less than three thousand miles an hour, but in a day and a half, when it hit the atmosphere, it would be going more than eight times as fast as that.
Everyone was still waiting for the helium tank to vent, which it still hadn’t done, but Deiterich said he couldn’t delay the burn any longer. Now Lovell found the earth in the telescope. At that time, the earth’s terminator caused it to have horns, like a crescent moon, and Lovell had been told to align one of the cross hairs so that it was just grazing the horns. “I hope the guys in the back room who thought this up knew what they were doing,” he grumbled. Reed, who had been the one to suggest this alignment, wasn’t worried. It was necessary to orient the spacecraft in two directions, and lining up the earth’s horns on one of the cross hairs would do the trick, because the shadow was always at right angles to the sun; without this trick Deiterich would never have let the TELMUs turn off the LM’s guidance system on the trip back. The method had been thought up as an emergency measure at the time of Apollo 8, the mission in which Lovell and his companions had made the first manned lunar-orbital flight, and when the procedures were read up in the afternoon, of April 15 he couldn’t believe what he was hearing, because even when he had first heard them during Apollo 8 he hadn’t dreamed he would ever have to use anything as risky as that. Meanwhile, Deiterich was battling with the weathermen, who kept predicting that the tropical storm Helen was approaching the landing site, and who wanted Deiterich to shift the target several degrees to the west. Deiterich said later that he “hounded those guys all over again.” He refused to budge the landing site. The maneuver PAD for the burn was already copied down in the spacecraft, and, besides, he felt he could fly over any storm the weathermen could produce simply by tilting the spacecraft’s attitude at reëntry so that it skipped more in the atmosphere.
The CAPCOM was as nervous about the burn as the astronauts, for when Lousma, who was now on duty, called out that there were three minutes to go, Lovell corrected him, pointing out that there were just two minutes—Brand had made the same mistake before the PC+2 burn. While they waited, the CAPCOM made sure that Swigert was sitting in exactly the same spot in the lunar module that he had occupied during the burn the day before—this time, the FIDO and RETRO had planned the burn with Swigert’s whereabouts in mind. Because the burn was such a small one, the big DPS rocket in the lunar module would be run at only ten per cent of its capacity, and the steering would be done with the thruster rockets instead of by aiming the DPS. With all the automatic equipment powered down, everything was done manually. All three astronauts were needed in this process, and it was as though several people were driving a car at the same time—one working the brake, one the accelerator, and one steering. Swigert kept track of the time for Lovell, and at Swigert’s word Lovell pushed the button that started the rocket. Haise kept the telescope cross hair just touching the horns of the earth, and made sure it stayed there by adjusting the spacecraft’s pitch, roll, and yaw with the hand lever that fired the thrusters. Since the spacecraft was perpendicular to its trajectory, the burn made it skid like a speedboat on a turn. The burn was completed at 10:31 P.M.
At about two o’clock Thursday morning, the helium tank finally blew out. The CONTROL noticed it almost as soon as Lovell did, and had Lousma ask him if he could see anything. Lovell reported lots of what he called “sparklies” going by outside the window. The spacecraft was wobbling about like a toy balloon jetting through the air. Lovell asked if that was really what they called a non-propulsive vent, and Lousma, after hearing what the effects had been, said he’d hate to see a propulsive one. When it was over, Lovell had to set up the passive thermal-control roll again. As he tried to get the earth and the moon following each other in the window, he and Lousma—both quite bleary-eyed—had a hard time deciding whether it was the earth or the moon that Lovell saw floating by.
“The moon went by the window at six degrees,” Lovell reported to Lousma.
“O.K. Earth at plus six. Thank you,” Lousma repeated.
> “That’s the moon. The moon!” Lovell corrected him.
“O.K., the moon. Thank you,” Lousma acknowledged.
A little while later, Lovell himself became confused about which it was that he was seeing. “The moon passed by at a minus-eight degrees,” he told Lousma, and then quickly corrected himself. “No, that’s the earth. The earth passed by at minus-eight degrees.”
“O.K., the moon went by at minus-eight degrees,” Lousma acknowledged, and Lovell was too tired to correct him.
When the CAPCOM asked about the other crew members, Lovell reported that Haise was lying in the tunnel with his head on the ascent-engine cover and Swigert was resting on the floor, tied down with a restraint harness. It was now three in the morning.
A few hours earlier, Aaron had presented his strawman timeline to a meeting of the entire Tiger Team. He jotted down the main points on a blackboard that had been set up at the front of the Support Room. Almost immediately, Commander John Young, the astronaut who was in command of the backup crew for Apollo 13 (and who, along with Duke, landed on the moon two years later, in April, 1972, during the Apollo 16 mission), raised his hand to object that Aaron had set the jettison of the service module too close to the jettison of the lunar module. The period between the two would be the busiest for the astronauts, he said, and they would need more time. Kranz agreed, and Aaron compromised by setting the service-module jettison an hour earlier. The meeting turned into an intricate bargaining session between the other flight controllers, who needed power, and Aaron, who didn’t want to give it to them. Sometimes Aaron won a clear-cut victory, but usually the results were mixed. Aaron wanted to delay starting up the command module’s instrument-cooling system until just an hour before reëntry, but Willoughby wanted to turn it on two and a half hours ahead of time. Aaron compromised at an hour and a half. He then had to find two amp-hours to keep the command module’s air-purifying system running for thirty minutes, because Dr. Hawkins pointed out that there might be pockets of carbon dioxide that the air-purifiers had missed. What with losing a few amp-hours here and gaining a few amp-hours there, Aaron was never exactly sure where he stood, but when the meeting ended he figured that he still had the sixteen-amp-hour margin that the Recovery Officers needed after splashdown.
After the flight controllers had revised the strawman timeline, they had to fill it out, smoothing the details, making sure that actions didn’t conflict, and blending them into a unified whole. The checklist would go through several revisions before Kranz was satisfied. In the simulator, Lieutenant Commander Thomas K. Mattingly—whose susceptibility to measles had led to his replacement on the flight by Swigert, and who two years later would be the command-module pilot for Apollo 16—tried out the timeline with Commander Young. They were on the lookout for technical errors; to everyone’s surprise there were none. Occasionally they crossed out an item they found hard to understand and replaced it with new wording. Aaron had a bad scare, for Young and Mattingly, when they were finished with their first run-through, reported that instead of a margin of sixteen amp-hours there was a deficit of ten. Aaron began looking over the timeline to see what else could be cut, but as he was doing so Peters, the Lead TELMU, sought him out to tell him he could have a little more power from the LM. As the astronauts neared the earth, more and more possibilities for trouble were ruled out; for example, there was no longer any possible chance that the flight would last an extra day—an eventuality the controllers had been saving consumables against. The TELMUs, however, would release only a little power to Aaron, for something could still go wrong—a point that Aaron was in no position to argue, since he liked to use it himself with flight controllers who wanted him to cut into his reserve electricity supply. However, Peters did release enough power to Aaron so that he could recharge the reëntry battery that had been used the night of the accident and was twenty amp-hours short of capacity. He suddenly found himself with a margin of ten amp-hours.
The astronauts became increasingly uncomfortable as the flight continued. The temperature within the command module had reached thirty-eight degrees. The astronauts stopped referring to the command module as “the upstairs bedroom” and began calling it “the refrigerator.” Some hot dogs they found there seemed to be frozen, they said. Lovell reported that any metal he touched conveyed the cold of space; it seemed to draw heat from his body and dispel it to the stars. Haise, with his kidney infection, was chilled to the bone; once, he shivered for four hours straight. Swigert’s feet were still cold because he had spilled water in his shoes two days earlier; the other astronauts, who were equipped for walking on the moon, had pulled on their lunar overshoes, but Swigert had none. Once again Lovell refused a suggestion from the ground that the men put on their space suits; not only would the suits be impossibly clumsy but because of the shortage of power they couldn’t be ventilated; the astronauts would perspire and might catch pneumonia. The walls and windows were dripping with water that had condensed from the cabin air; it was like an icy rain.
The cold in the LM prevented the men from sleeping, and lack of sleep made them feel even colder. Sleeping in the LM was further prevented by noise from the craft’s instrument-cooling system, which rattled and hissed like the pipes of a locomotive as the water slowly steamed into space. Moreover, a napping astronaut was bound to wake up whenever one of his mates was talking to the CAPCOM; without an amplifier, an astronaut had to shout to make the CAPCOM hear him. The Flight Surgeons worried, because sleeplessness could reduce the astronauts’ efficiency. During the three and a half days between the accident and the landing, Lovell had eleven hours’ sleep and Swigert had twelve—an average of about three hours a day, and none of it was what either astronaut could describe as “good” sleep.
Sometimes Dr. A. Duane Catterson, the Deputy Director of Medical Research and Operations at the Manned Spacecraft Center, would join the Flight Surgeon at his console, and the two would listen in silence to the astronauts’ voices. The doctors worried as much about the astronauts’ systems as the flight controllers did about the spacecraft’s. The cold and the exhaustion wouldn’t seriously harm the astronauts, but lack of water would. A water tank in the command module, which Dr. Hawkins had thought the astronauts could tap, had now frozen solid; the spacecraft was carrying an internal iceberg. In the four days between accident and splashdown, each of the astronauts drank about a pint and a half of water; they were allowing themselves only six ounces a day—less than a fifth of the normal daily minimum requirement of thirty-two ounces. Dehydration alters the body chemistry with respect to blood, enzymes, and steroids in a way that makes it more difficult to cope with emergencies, but since the astronauts were not particularly thirsty, they would have no warning of this situation. Dr. Catterson worried specifically because water is essential for dissolving certain electrolytes in the body that are important for the transmission of impulses along nerves; without liquid, thought and movement deteriorate. Dr. Hawkins, for his part, worried because the body excretes more potassium when it is dehydrated, and potassium is a vital electrolyte in brain cells. Both doctors feared that the astronauts would start making errors, and, as it turned out, their fears were justified.
Dehydration was a problem in another way as well, for electrolytes are part of the body’s defense against disease, and both Dr. Catterson and Dr. Hawkins worried because lack of water could make the astronauts more susceptible to infection. The likeliest place for such an infection, they knew, was the kidneys, which try to retain fluid and consequently never purge themselves. The doctors were unaware that Haise was already developing a kidney infection. Afterward, Dr. Catterson said that if the flight had lasted much longer Lovell and Swigert would almost certainly have developed similar infections, or infections of other sorts, and the astronauts would have been increasingly unable to cope. In their exhausted condition, their nervous energy would have deserted them at some point, and, in spite of themselves, they would just have drifted off to sleep.
As for what the ast
ronauts were actually feeling around that time, it was as much as anything an incessant worry about their reëntry to earth. The flight controllers were worried, too. Fears crowded in from all directions. Around three o’clock on Thursday morning, a dozen members of the White (or Tiger) Team gathered at the CAPCOM’s console in the third-floor Control Room while the CAPCOM asked the astronauts some questions that the White Team had prepared about the reëntry, which was still projected for noon Friday. In the spacecraft, Lovell was the only one up. The White Team was not absolutely certain that the seal of the command module’s hatch was airtight, and the flight controllers had to find out whether Lovell wanted the crew to wear space suits during the reëntry. If the hatch wasn’t tight, the astronauts would lose their oxygen. (A failure of this sort was to kill three Russian cosmonauts in 1971.) They would run a test on the hatch’s integrity just before reëntry—a standard procedure—but at that point there wouldn’t be enough time for them to get into their space suits if the hatch was found to be leaking. The White Team suggested to Lovell that the astronauts put on their space suits at the very beginning of the reëntry procedures, some six hours before splashdown. Lovell was worried that the ground knew something about the hatch that he didn’t know, but Lousma assured him it didn’t. Lovell pondered the matter for some time, and in the end he decided against the space suits, for the same reasons as before—their bulk and stiffness.
Thirteen: The Apollo Flight That Failed Page 10