It didn’t sound good to Aaron, for it meant that some bit of equipment in the command module was on when it should have been off, and until he found what it was it would continue to draw current that would be badly needed after splashdown—for the radio beacon that would signal the craft’s location and for other, unforeseen circumstances. “We’d blown half our margin. That really threw us,” Aaron said later.
Without telemetry from the command module, it was almost impossible to find out what piece of equipment had been mistakenly left on. It was precisely to avoid this type of situation that Kranz had earlier got Swigert to read off the position of each of the switches in the command module. Now there wasn’t time to do that again. And at this point Aaron didn’t particularly want Swigert to know he was worried about the drain, for the solution might yet prove to be a simple one and he would have alarmed the astronauts unnecessarily. Aaron did spell out his fears to Kranz, however, and Kranz didn’t seem unduly alarmed—the way a skipper on a ship wouldn’t be concerned with a problem in the engine room; at least, until it was shown to be insoluble. He had half a dozen other problems to think about. He knew that his flight controllers were naturally nervous about problems in their own areas, and he had enough confidence in them to assume that they would find the trouble and fix it.
Such sang-froid on the bridge didn’t make the problem on the lower deck any easier. Confident though Kranz may have been about his Lead EECOM, Aaron and the other EECOMs were “sweating blood,” as Aaron said later. They tried to guess some of the most obvious items that might be on when they should be off, such as certain lights in the command module. Swigert reported that they were off. Next, the EECOMs suggested that some of the heaters for the command module’s thrusters might have been mistakenly plugged into Main Bus A, but that was not the case. Since it looked as if it would be some time before the EECOMs came up with the right answer, Aaron asked Kranz to have the reëntry battery disconnected and avoid wasting any more power now.
As the time for the power-up with the reëntry batteries drew closer, Kerwin, who was anxious to get on with it for the sake of Swigert’s nerves, brought occasional gentle pressure to bear on Kranz. “Shall I give ’em a go?” Kerwin asked. Kranz was determined not to do so before the checklist said to, and he was watching one of the electronic clocks at the front of the Control Room. He told Kerwin to wait. Aaron, who was still fearful that the batteries would be weak, like an automobile battery on a frosty morning, reminded Kranz that the astronauts should not draw very much power from them at first. He told Kranz he had a list of equipment that could be turned off if the batteries showed signs of flagging.
“What do you say now, Flight?” Kerwin asked.
Kranz waited until the electronic numbers indicated that there were precisely two and a half hours until splashdown. “O.K., go ahead,” Kranz said.
In the command module, Swigert switched on the reëntry batteries and then shut off the power coming from the LM. Lovell and Haise shut down some batteries in the LM that were no longer needed. Then Haise joined Swigert to help him turn on more of the command module’s equipment.
Now, with the command module’s reëntry batteries on the line, the power-up could really get under way. And it was high time, everyone felt, because its computer had to be loaded, its guidance platform aligned, the LM jettisoned, and a number of other things done before entry interface, the point, four hundred thousand feet above the earth, where the first thin traces of the atmosphere begin. It was from this point, just two hours away, that the spacecraft would start its final descent. Even with this much time, getting the guidance and navigation equipment, the radio, and all the rest of the systems up and on the line would take some time, particularly in view of Aaron’s caution about not overloading the batteries at first. Nevertheless, both the astronauts and the flight controllers seemed happier now. There was even some laughter. Swigert, as he pressed the switches, felt like a captain who had been given a new ship after his first one had sunk. Aaron felt the same way, and so did Seymour Liebergot, the EECOM who had been on duty when the command module was shut down; he was sitting next to Aaron now. About the first piece of equipment that Swigert turned on was the command module’s telemetry, and soon the electronic displays on the EECOM’s console flickered on. To Aaron and Liebergot, this was the moment when the spacecraft really came alive again. “You saw it was cold, and you could see it warming up,” Liebergot said later. “It was like having the machinery in a ship’s engine room suddenly come to life.”
When Russell, the Lead GUIDO, took a look at the first telemetry coming from the command-module computer, he saw signs of trouble; there was what he called a “flashing thirty-seven”—the number thirty-seven, which was the code for a serious malfunction, flashing from a field of other numbers to attract attention. It made him wonder whether the computer had been damaged by its prolonged exposure to cold. However, the trouble turned out to be merely that Swigert had failed to hold down long enough one of the buttons he had pressed to get the computer started.
The telemetry continued to be weak and unsteady, so the INCO, the flight controller responsible for the spacecraft’s radio; asked Kranz to get the astronauts to switch to another omni antenna. The change didn’t help, and large parts of the telemetry were lost. Even so, the EECOMs began scanning their screens for clues to what might be causing the power drain. At length, they found the trouble: the astronauts had inadvertently turned on a couple of switches, among them one for part of a backup control system. Aaron asked Kranz to have them turned off. Swigert flipped the switches, without fully realizing the importance of the request.
With his margin regained, Aaron settled down to follow the power-up. On his console he had a sheet of graph paper on which he had drawn a descending blue line representing the maximum amount of power the astronauts could use at any time during the next two and a half hours and still have enough left after splashdown. As Swigert turned on more equipment, Aaron put dots on the graph to indicate the amount of electricity left, and he connected the dots with a pencil line. As the new line lengthened, he was reminded of some of the discussions of the last few days. When Swigert turned on the fans for the command module’s lithium-hydroxide system, Aaron noted that the air in the command module was already clean—scrubbed by the mailboxes in the LM, just as he had told a Flight Surgeon it would be. The argument had cost him two amp-hours. A little later, when Swigert turned on the glycol cooling system for the electronics—the subject of a battle Aaron had lost to a GNC—Aaron couldn’t help noticing that the electronics were already so cold that they wouldn’t need any additional cooling. Aaron did not suggest turning off any of this unneeded equipment, however, because the power had already been accounted for. Besides, Swigert was already moving on to the next major item on the checklist.
Swigert saw he was getting to the point where he would have to align the command module’s guidance platform. It was the most critical alignment of all, because the guidance system would have to keep the spacecraft precisely within the reëntry corridor, which was only one and a half degrees wide. As Russell had realized earlier, the big problem would be getting a precise navigational fix, preferably on the stars. But whenever Swigert looked out the window, all he could see was a blizzard of what he called “little fluffy white objects”—presumably nuggets of ice that had formed from condensed steam from the LM’s instrument-cooling system. Kerwin thought it sounded as though Swigert would have to forgo the star check and settle for a less accurate one based on the sun and moon. Russell had been holding on to the maneuver PAD for the sun-and-moon check, in the hope that it wouldn’t be needed. Deiterich felt it was not reliable enough for the kind of accuracy required this close to the earth. Kerwin asked for the PAD now, and Russell handed it to him. Since there was a greater possibility of the astronauts’ landing off target if the sun-and-moon check was used, the Recovery Officers once again plagued Aaron for a commitment on the amount of electricity that would be left after spl
ashdown.
The astronauts could still try to get the more precise star check, though, and Kranz asked Kerwin to begin sending up Russell’s coördinates for positioning the spacecraft, so that it could find the guide stars, any two of which Swigert would need in order to get the fine alignment. In the meantime, Russell was sending information to update the spacecraft’s computer, and after he sent the first of four uplinks he got no acknowledgment back to indicate that it had been safely loaded. Again Russell thought of cold damage. However, the main problem just then had to do with radio communication, which still had not been firmly established with the command module. Russell listened in on the loop over which radio technicians at NASA’s network of tracking stations around the world could talk to each other. Some technicians at the station in Honeysuckle Creek, Australia, were having trouble with what they called lockup—locking their antenna onto the spacecraft’s signal. They kept picking up the signal and then losing it. A technician with an Australian accent was repeating over and over again the refrain “We’ve got lockup. … No, we don’t!”
Kranz asked the INCO if he had any idea what the trouble was. The best idea the INCO could come up with was that perhaps the lunar module was causing interference by getting between the command module’s antenna and the station in Australia—a possibility that had never been anticipated, because lunar modules were not normally brought back to earth. The INCO suggested that the astronauts bring the spacecraft to a different attitude to get the LM out of the way. Russell was against this proposal, because the spacecraft was now at the proper attitude for the star check and he didn’t want to lose it. Fortunately, the radio problem cleared up a little later, when the NASA tracking station at Guam took over communications with the spacecraft. (The INCO’s guess about the LM’s causing interference was afterward proved correct.) Now voice communication was established with the command module, and Kerwin could talk directly to Swigert without having to relay messages through the LM.
When Kerwin finished sending up the coördinates for the star check, Swigert was as skeptical as Kerwin and Russell had been about his chances of getting even one of the stars lined up in the command module’s sextant. He peered through the sextant, which was set through the spacecraft’s hull just above his seat and (unlike a similar instrument in the LM) could be swivelled without the need for moving the entire spacecraft. Swigert reported that the snowstorm of fluffy white balls glinting in the sunlight was still obliterating all the stars. He was already more than five minutes behind the timeline, and the earth outside the spacecraft window was getting bigger.
Swigert had already transferred to the command module the alignment from the lunar module’s guidance platform which Lovell and Haise had set up earlier that morning. It was not a very reliable one, not only because it was already several hours old but also because errors could have crept in during the transfer. Lovell and Haise had shouted the angles through the tunnel, and if the spacecraft had rolled, pitched, or yawed before Swigert could punch them into the command-module computer there would have been errors. Still, it would be easier for Swigert to tweak up an existing platform, crude as it may have been, than to start from scratch.
Swigert radioed down that wherever he turned the sextant the blizzard of ice particles still covered the stars. One of the flight controllers suggested to Kranz that they recommend a couple of guide stars on the side of the spacecraft away from the sun, where the spacecraft’s shadow could cut the glare. He handed Kerwin the sextant angles for two such stars, Altair and Vega. Swigert swiveled the sextant toward Altair. Doing so was a departure from the usual way of aligning the platform, which was done by asking the computer to aim the sextant at a particular star, but Swigert felt that his present alignment was so crude that he didn’t want to waste the time it would take the computer to guide the sextant to a position that could only be the wrong one. When he put his eye to the lens, he still couldn’t see anything at all. Kerwin advised him to turn off a light, in the hope that he could see better. Meanwhile, Lovell, in the LM, who could see from the window that the earth was getting bigger at an alarming rate, shouted to Swigert to hurry up.
With the light off, Swigert found Altair easily. Occasionally, a fluffy speck of ice—black now, in the absence of sunlight—eclipsed the star, but otherwise Altair stayed firmly in view, a solid benchmark in the sky. As soon as he had it centered on the sextant’s cross hairs, he ordered the computer to find the same star and then sat back to wait until the amount by which the computer was off—the platform error—appeared in the gauge. This had five windows for numbers, but when the five numbers appeared they were all zeros; Swigert said he got “five balls.” There was no error at all. Haise’s and Lovell’s rough alignment on the sun and moon and its transfer to the command module after several hours had been entirely accurate—an extremely unlikely circumstance. Quickly, Swigert found Vega and repeated the check; he got five balls there, too. Suddenly, the astronauts were five minutes ahead of the timeline.
For the first time, Kerwin said later, he let himself think that they were going to make it.
As soon as the command module’s guidance platform was aligned, Lovell, alone now in the lunar module, began to maneuver the spacecraft to the right attitude for the jettison of the LM. Following the method that Charles Duke had found to be practicable in the simulator, Lovell rolled, pitched, and yawed the spacecraft so that he could see the succession of guide stars out the window, as if they were buoys leading him to port; since he wasn’t looking at them through a sextant, he wasn’t as bothered by glare as Swigert had been. As it turned out, the guide stars were less like buoys leading to a safe harbor than like buoys skirting a shoal, for the path he was following from star to star brought the LM’s guidance platform close to gimbal lock—in spite of the fact that the series of stars had been changed since Duke’s trials in the simulator. In the Trench Deiterich, Reed, and Russell were puzzled. Whenever Lovell was about to jam the gimbals and lose the platform alignment, Loden, the LM’s Control Officer, called out a warning to Kranz, and Kerwin relayed it. Then Lovell would back up a bit to pick a new route. It was slow going, and Lovell was getting impatient. Entry interface was just an hour and a half off; they were only about eighteen thousand miles away now, and their speed had increased to almost eleven thousand miles an hour. Though no one was aware of it, the command module’s guidance platform—more important now than the LM’s—was being maneuvered close to gimbal lock, too. The flight controllers, with their attention focused on Lovell and the LM’s platform, forgot all about the alignment that had just been set up in the command module, until Swigert called out that it was in danger of being lost. So much time and effort had been invested in aligning this platform that some of the flight controllers thought Swigert must be joking, but he wasn’t. He shouted to Lovell to stop the maneuvering, and then he called some directions through the tunnel, rather as if he were a pilot guiding a big ship around a sandbar. “A little more pitch! A little more pitch!” he called, and when the danger was past he shouted, “Now you can begin to roll!” Lovell grumbled to Kerwin that he had picked a lousy attitude for jettisoning the LM, and Kerwin told him to take his time, since they were a little ahead of the timeline.
Lovell, however, was in no mood to wait. The earth was looking less and less like an ethereal celestial body and more and more like a big solid landmass dead ahead. When at last he got the spacecraft to the proper attitude, he put the LM’s Primary Guidance and Navigation System on its automatic setting, so that the LM would be maintaining the spacecraft’s attitude until it was jettisoned. Then he told Kerwin he was planning to bail out of the LM. Kerwin said he couldn’t think of a better idea. Before scrambling through the hatch, Lovell took a last look at the LM’s cockpit, crammed to the ceiling with debris collected during the six days of the flight. He thought that it looked like a packed garbage can. He shut the lid, the LM’s hatch, behind him.
The three astronauts were together now in the command module. Swig
ert switched on the oxygen surge tank that Kranz and Liebergot had hastily ordered isolated the night of the accident, and the command module’s own oxygen flooded the cabin. On the ground, too, everyone’s attention turned to the command module. Kranz asked Aaron how it was doing on power, and Aaron, after consulting his chart, said that it was doing well—that if things kept on going the way they were going then, there would be plenty left after splashdown. Moments later, however, he had to amend his estimate, for he found another unexplained drain on the batteries. After some digging around in the telemetry, he discovered that Swigert had left on the power that ran the sextant. With this remedied, the margin was in good shape.
Buck Willoughby, the Lead GNC, had a more serious problem. Willoughby’s telemetry was indicating that at least two of the command module’s thruster jets were still cold, though Swigert had turned on their heaters a couple of hours before. As the GNCs had told Aaron a day and a half before, if fuel had become frozen inside their nozzles, they mightn’t be able to keep the command module at the right attitude during reëntry. Willoughby told Kranz he would like to test-fire the thrusters now. Kranz, however, didn’t want to risk knocking the spacecraft out of the jettison attitude that Lovell had had such a hard time setting up. Kranz asked Willoughby if he couldn’t wait to test the thrusters until after the LM was separated, a wait of less than half an hour.
Kranz needn’t have been so meticulous about the spacecraft’s attitude. Deiterich, who had been uneasy since the unexpected brushes with gimbal lock, now checked his telemetry to make sure the spacecraft was at the right attitude for jettisoning the LM, and he thought that things didn’t seem quite right. Under the best of circumstances, nothing upsets a RETRO or a FIDO more than an attitude error, but this time there was the added problem of aiming the cask of radioactive fuel that Deiterich had promised the Atomic Energy Commission he would set down off New Zealand. Deiterich asked Reed, the Lead FIDO, what the correct attitude angles were supposed to be, and together the two flight controllers discovered that Lovell had brought the spacecraft’s angle of yaw ninety degrees from where it should have been. In addition to explaining the close calls with gimbal lock, the error meant that the lunar module was going to be jettisoned toward the northeast instead of the southeast.
Thirteen: The Apollo Flight That Failed Page 13