Just as Kranz expected, he got a call from Reed, the Lead FIDO, who asked if there was any chance of using the primary system for the midcourse correction, because it would make for a more precise burn. Kranz said that he would consider it but that first he had to check with the CONTROL. TO his surprise, the CONTROL on duty (the Lead CONTROL, Harold Loden, was not present) gave his approval. Kranz then checked with Russell, the Lead GUIDO, who also went along with the idea, so Kranz gave Reed permission to use the primary system, though he wasn’t sure he had heard the end of the matter. Kranz liked to arrive at decisions by consensus, but as he asked a question here, answered one there, and passed an instruction to the CAPCOM to transmit to the astronauts, there could be no doubt that he was the center of the whole operation. As a rule, the conversation on the loop was terse, with long silences. Kranz’s eye would rove around the room, and every once in a while he would seek information from one man or another. Once, he broke the silence to ask the CONTROL how he was coming; the CONTROL answered that the astronauts had already begun to use the LM’s primary guidance system to hold the spacecraft at the proper attitude. After another silence, Kranz asked Deiterich if he was satisfied with the way the crew had stowed equipment in the command module for balance the day before; Deiterich said he was.
After another, longer silence, Kranz asked Peters, the Lead TELMU, how he was doing; Peters replied that he was doing fine, though the LM’s batteries were beginning to shade off a bit as a result of the LM’s early power-up.
So far, the LM had not begun to supply power to the command module, apart from recharging one of its reëntry batteries. A little after five in the morning, Swigert entered the command module to start drawing a little electricity from the LM—enough to turn on some of the heaters to warm electronic equipment inside the command module and, in particular, to de-ice the thrusters on the outside. (The GNCs, who were worried about the thrusters, had got further with the TELMUs than with Aaron.) The transfer of power to the command module began about an hour earlier than the checklist specified because, in addition to the LM’s new found fatness, Peters, the Lead TELMU, had suddenly realized it wouldn’t cost the LM any more of its water for cooling electronics—water being even more of a pacing item in the LM than electricity—because the command module would cool its own instruments with its glycol system. As the circuits were not set up for the LM to power the command module—Lovell’s worries on that score had been quite reasonable—Aaron and Peters had thought up a way to trick them. Accordingly, Swigert plugged an entry battery into Main Bus B and drew just enough power so that the command module was in fact feeding a little to the LM; then, with the circuits between the two modules established, Swigert reversed things so that electricity from the LM was now flowing into the command module’s Main Bus B. Swigert was relieved that this bus, the first to fail after the accident, proved to be in good condition.
For the first time since the accident, he felt as if he had something to do. The night of the accident, just after the command module had been powered down, Swigert told the other two that it was up to them to get the spacecraft home; now it would be largely up to him. As Swigert took his seat in the command module, Mattingly took a seat in the Control Room next to the CAPCOM. Although Mattingly had been working on the simulations to verify the checklist almost incessantly for the past three days, he looked spotless and crisp. At about the time that Swigert and Mattingly took their seats, Kerwin relieved Lousma as CAPCOM.
With all the early power-ups resulting from the LM’s surplus, Kranz now thought it wise to warn the astronauts that under no circumstances were they to jump the gun and power up the command module on its entry batteries before the time stipulated in the checklist, two and one half hours before splashdown. The next step was to plug the heaters for the command module’s thrusters into Main Bus B, to start deicing them; and in the Control Room Kranz alerted Peters that at any minute he could expect to see the drain on the LM’s batteries. This would be the first use of the new circuitry. Peters watched for it on the LM’s telemetry, which was powered up now—but the drain did not show up, and some of the flight controllers worried that the reversal of the circuits had not worked after all. The trouble, though, was that Swigert hadn’t pressed the switch yet because he was having difficulty deciphering the checklist he had copied the day before. “Either I copied the circuit breaker wrong, or—I can’t read it …,” Swigert said. “Would you give me that again? I just can’t read my own handwriting.” (Even so, he said later that he was glad he had taken the trouble to write out the checklist longhand, without abbreviation, or he might have had even more trouble.) On the ground, Mattingly put his finger on the proper place on the checklist to help Kerwin, who read up the correct instruction. At length, Peters reported to Kranz that he could see the drain on the LM’s batteries, and this was taken as evidence that the command module’s thrusters were being warmed.
By six-fifteen, the glassed-in gallery at the back of the Control Room was beginning to fill with visitors who wanted to be present for the mid-course correction. This time, in addition to the NASA brass, there were a number of congressmen. The burn, less than an hour away, would be a small one, done by the lunar module’s thrusters, which would fire forward to alter the trajectory. One reason for the burn was that Deiterich wanted to make sure the astronauts landed as near the recovery ship as possible; the sooner the astronauts were picked up the better, if only because Tropical Storm Helen was still charging erratically about the Pacific. The spacecraft might have come in all right without the burn, but on its present course it would come dangerously close to the shallow top of the corridor, and Deiterich wanted to center it against any further shallowing—if the rate increased, it might not stay within the corridor. Indeed, Reed was then finding that the trajectory was a good deal shallower than it had been when he arrived, four hours earlier, and he still couldn’t figure out why. He and Deiterich therefore decided to increase the burn from two feet per second to three. Even with the increase, the burn was still small enough so that it could be done with the LM’s thrusters. However, they would have to fire for twenty-three seconds—a long time for thrusters—and Loden, the Lead CONTROL, was worried about running out of fuel.
Loden, wearing a bright-yellow shirt, had just taken over the CONTROL console; he had been working elsewhere on some other matters and therefore had not been involved in the decision to use the LM’s primary guidance system for the burn instead of the more economical secondary system. The astronauts had been using the primary to hold their attitude, and it was on an automatic setting, so the thrusters fired short bursts every time the attitude strayed. Since the LM had to juggle the command and service modules as well, the use of fuel in the automatic setting was more than Loden could tolerate. He complained to Kranz; he said they should switch over and hold their attitude manually as they waited for the burn. Kranz agreed. Then, when it appeared that some trouble in the primary guidance system could not be cleared up, Loden suggested that they do the burn with the secondary system. “Do the burn in secondary?” Kranz asked. The argument he had avoided earlier was about to start up. Reed, the FIDO, gave a distressed laugh and asked to have matters left the way they were. Kranz was quite good at settling arguments. He tended to listen quietly, ask a question or two, and then suddenly announce a decision. In this case, after a brief discussion, he told Reed no.
The CAPCOM passed the word to the astronauts. With the burn being done by the less accurate secondary guidance system, the Recovery Officers badgered Aaron to give them a commitment about how much power would be left in the entry batteries after splashdown; the spacecraft’s radio beacon might have to beep a long time before it was found. Aaron, however, could give them no firm figure.
Although the MCC 7 burn was the smallest the astronauts had done, they had the most trouble with it, for exhaustion and dehydration were wearing them down. The flight controllers had to watch the astronauts’ every move closely. On the telemetry screen at his conso
le, Russell, the Lead GUIDO, was concentrating on following some data that Lovell was punching into the LM’s computer for the correction. The numbers had been prepared by Deiterich, and Russell had a copy of them. Suddenly, Russell spotted on the telemetry screen the code number “P 40” where a “P 41” should have been. Lovell, who had stinted himself on water even more than the two other astronauts, had erroneously ordered the computer to use the LM’s big DPS rocket instead of the thrusters. “Should be forty-one, I believe, Flight—not forty,” Russell said quietly to Kranz, and Kranz told the CAPCOM to take note.
The MCC 7 burn caused trouble almost up to the moment the rockets were fired. In bringing the spacecraft to the attitude for the burn, Lovell rolled it sixteen degrees in the wrong direction. Deiterich, the Lead RETRO, didn’t notice the error until he heard someone else mention it over the loop. Then, before he could say anything himself, he heard a second flight controller say that the error was unimportant, because the midcourse correction wasn’t sensitive to being sixteen degrees out of attitude. “That griped me. During a landing, everybody in the Control Room thinks he’s a RETRO,” Deiterich said later. He came on the loop and said the burn certainly was sensitive to being sixteen degrees out of attitude. This was not the only time the astronauts made such an error. Moreover, the people on the ground seemed to catch their increased proclivity for errors. When Kerwin was telling Lovell how much time there was before the midcourse correction, he gave him a mark of ten minutes and then corrected himself, for the burn was only nine minutes off. Like Brand before the PC +2 burn and Lousma prior to the MCC 5 burn, Kerwin had been looking at the wrong electronic clock at the front of the room.
The burn itself, however, went off smoothly, and almost immediately Reed began checking vectors. He was able to get a hack on the trajectory sooner than before, because the spacecraft was approaching earth so much faster and the trajectory was beginning to curve slightly as it did so, making more of a difference between vectors. Besides, the spacecraft was near enough now for smaller radar dishes in the tracking network to get a line on it, and therefore the quality of radar data available to Houston was better. In a few minutes, Reed reported to Kranz that the spacecraft had apparently been tweaked back to the center of the corridor, despite the use of the less accurate guidance system. The spacecraft was only forty-one thousand miles away now, and its speed had increased to seven thousand miles an hour. The astronauts reported that the earth almost filled its window.
The real business of getting home was about to begin.
As Haise and Lovell, in the lunar module, maneuvered the spacecraft to the correct attitude for jettisoning the service module, Swigert, in the command module, made preparations for firing the explosives, called pyros, that would sever the service module from the rest of the spacecraft. Swigert was flicking a number of switches in front of him to open the circuits leading to the explosives—an operation called arming the pyros. It was risky, in the same way that taking off the safety catch of a gun is; if Swigert wasn’t careful, the pyros could explode if he pulled one more switch. Normally, the ground checked the pyros before the arming, but at the moment it couldn’t, because there was no telemetry from the command module. As a number of different pyros were on the same circuits, there was danger that the wrong thing might be jettisoned—the lunar module, for instance. In fact, the switch for jettisoning the LM was right next to the switch for jettisoning the service module, and the previous day Swigert, afraid he might press the wrong one, had put a piece of tape over the LM-jettison switch and attached to it a slip of paper bearing, in big red letters, the word “NO.” Then he got Haise to verify what he had done. Now Haise, who wanted to be sure nothing went awry, and didn’t want to be in the wrong module if it did, floated into the command module to help Swigert with the jettison. He asked Swigert whether he shouldn’t check with the ground before arming the pyros, but Swigert, pointing out that there was no telemetry, told Haise just to stand by and put his fingers in his ears.
The jettison involved all three astronauts. Haise returned to the lunar module, and he and Lovell fired the LM’s thrusters so that the spacecraft moved forward, with the service module at the front, at half a foot a second; then Swigert, in the command module, fired the pyros to separate the service module; and, finally, Lovell and Haise reversed the thrusters so that the service module and the rest of the spacecraft parted, at half a foot a second. Deiterich had made sure the speed was slow enough so there would be time to photograph the damage. The day before, Charles Duke and a photographer, in the simulator, had calculated that the best view of the service module would be from one of the windows in the command module, and, accordingly, Swigert was stationed there with the best camera, a Hasselblad equipped with a telephoto lens. But now when he looked out the window, his camera at the ready, he saw nothing but black sky. Since a command module had never before jettisoned a service module while it was itself attached to a lunar module, no one had been able to predict exactly what would happen. When Swigert fired the pyros, the craft had rocked unexpectedly at the explosion—the astronauts later described the movement as a “rippling”—and none of the modules wound up quite where they were expected to.
Swigert heard excited voices from the lunar module, where the others had just caught sight of the service module. He heard the whir of Lovell’s movie camera and the steady click of Haise’s still camera, which had been loaded with color film. Neither of those cameras had the resolution of Swigert’s Hasselblad. The service module—a squat silvery cylinder with a huge rocket nozzle at one end—was spinning fast. Lovell, who had been the first to spot it, said, “O.K., I’ve got her. … And there’s one whole side of that spacecraft missing. … Right by the high-gain antenna, the whole panel is blown out, almost from the base to the engine.” That was the first anyone knew of the service module’s having burst open. The gash ran down its length like a long slice in the hull of a ship. Lovell strained to get a look inside the damaged hull, but by the time it came into view it was a hundred feet away, and it was rolling so fast that peering in was difficult. Two of the three fuel cells—canisters like depth charges—glinted as the sun struck them, but on the shelf supporting them there was such a welter of broken metal and jagged bits of Mylar insulation that Lovell couldn’t make out whether the oxygen tanks were there or not.
Haise caught sight of the rocket at the rear of the service module. “It looks like it got to the [rocket], too. … Just a dark-brown streak. It’s really a mess,” he said. As the service module kept rolling and pitching, he saw debris hanging out of the gaping gash in its side. It looked to him as if the explosion had gone through several stages. As Deiterich listened to the reports on the force of the explosion, one thought filled his mind. He knew that the ruptured oxygen tank had been quite near the ceramic heat shield at the bottom of the command module, and now that the tank failure was shown to have been so forceful, he was gripped by the fear that the command module’s heat shield had been damaged, possibly even cracked. “I think everybody in the room had the same idea at the same time,” he said later. “Everybody knew where the oxygen tank was. Nobody said a word about it. There was nothing anybody could do.” Up in the spacecraft, the same thought was occurring to Haise.
Lovell shouted to Swigert that he should bring his telephoto camera into the lunar module; Swigert hurried in and practically climbed on Lovell’s shoulders to get his shots. Because the service module was tumbling, the damaged part was usually obscured by shadows so dark that it was impossible to photograph the wreckage, and because the lunar module itself was rolling, the service module wasn’t always in sight. Swigert had to run back and forth as it kept popping up at one window and then another. The astronauts wished they could steady their attitude for photography, but, in order to obtain the best tracking data, Deiterich had prohibited use of the thruster jets. For a time, they lost sight of the service module behind the command module, and when it reappeared it was over four hundred yards away and receding rapidl
y. The moon was in the background now, glaring white. They shot away with their cameras until the service module was the merest speck in the distance, the way shipwrecked sailors might keep gazing at the spot where their boat had sunk.
Kranz did not spend much time thinking about the explosion and the gash in the service module, for he regarded the mission as a flight of stairs to climb, and now that he was close to the top he didn’t want to concern himself with anything that had happened on the bottom step. The time was approaching when Swigert would start drawing electricity from the reëntry batteries to power up the equipment that the command module needed for reëntry. Because the LM was supplying power to Main Bus B, the reëntry batteries would initially be plugged into Main Bus A, and Aaron now told Kranz he would like to get Swigert to test Main Bus A by plugging one of the reëntry batteries into it and taking a Voltage reading. Kerwin passed the request to Lovell, who shouted it through the tunnel. (It would be some time before the command module’s radio was powered up.) A couple of minutes later, Swigert passed word back that he was getting a reading of two amps on the bus, and Kerwin said that sounded good to him.
Thirteen: The Apollo Flight That Failed Page 12