The men in the Trench never feel more like pilots than during a rocket burn. As soon as the GUIDO got the trajectory information from the FIDO, he punched the numbers into a white keyboard in front of him, preparatory to loading (or, as GUIDOs say, “uplinking”) the data into the computer aboard the spacecraft. After the information was received aboard the spacecraft, a confirmation copy of it—a sort of return receipt—popped up on the television screen on the GUIDO’s console, and he checked it, then pressed a button ordering the spacecraft computer to accept the data. Meanwhile, the RETRO was writing out the instructions for the burn. On a green sheet of paper lined into boxes called a maneuver PAD—a NASA acronym for “pre-advisory data”—he jotted numbers indicating the exact instant the rocket should be turned on, the length of time the rocket should fire, and the attitude of the spacecraft while it was firing. The CAPCOM read these numbers up to Lovell, who jotted them down on an identical maneuver PAD, read them back for confirmation, and finally punched them into his computer.
The mechanics in the second row were as busy as the pilots in the Trench. The Control Officer, whose responsibility for the lunar module corresponded to that of the GNC for the command module, had to modify a checklist for the powering up of the LM’s main rocket—the Descent Propulsion System, which Control Officers call DPS (pronounced “dips”). It was at the opposite end of the combined Apollo spacecraft from the big rocket in the service module, and although it wasn’t as powerful as that rocket, it could build up the necessary thrust by being burned for a longer time. There was some question in everyone’s mind, though, whether the DPS would work at all, for nobody yet knew the full extent of the disaster—perhaps the DPS was out of commission, too. The rocket swung on gimbals to facilitate landing on the moon and also to allow for shifts in the center of gravity during firing; at the moment, the gimbals were set for the lunar landing. The coming burn would be what Control Officers called a “docked DPS,” to denote that the LM was docked with the command and service modules and the DPS would be pushing all of them—a tricky setup, because there was some flexibility in the connection between the LM and the command module, and the LM would not necessarily be exactly lined up with what it was pushing. Just before the burn, the CAPCOM radioed up to tell the astronauts that the nozzle of the DPS rocket was not aimed perfectly for a docked-DPS firing, and the astronauts hastily “trimmed the gimbals”—a little the way a seafarer trims his sails. If the aim hadn’t been rectified, the spacecraft could have tumbled during the burn and gone off course. The Control also reminded the astronauts to open up the LM’s four landing legs, which were folded up beneath the rocket, in the way of the flames. Then, as the astronauts were making a last-minute check of their control panels, one of them mentioned that a switch that could have jettisoned the bottom half of the LM—the part ordinarily left behind on the moon, which contained the DPS rocket—was on. The CAPCOM told the astronauts to turn off the switch.
At two-forty-three in the morning, five and a half hours after the accident, Lovell’s left hand pushed a button. For thirty seconds, Lovell felt himself pressed gently toward the floor—the only physical indication he had that the rocket was firing. A planned minor correction later would aim the craft into a narrow corridor through the earth’s atmosphere which would bring the astronauts, in less than four days’ time, to the Indian Ocean. The Recovery Officers had never stationed a ship in the Indian Ocean, and they had to act quickly now. The nearest United States Navy ship was the destroyer Bordelon, which was cruising off Mauritius. They discovered that the Bordelon was one of several Navy ships that had been modified to take a special crane for picking command modules out of the sea. However, the Recovery Officers would have to order the crane flown from Norfolk, Virginia, to Mauritius. They were banking on the fact that the Bordelon would get to port, pick up the crane, and be at the splash-down site, seven hundred miles away, before the astronauts could get there.
The rest of the night was largely a holding action. In particular, the TELMUS were trying to hold on to the LM’s consumables—a task that recurrently brought them into collision with the other flight controllers. As soon as the rocket burn was over, the TELMUS requested that the astronauts begin powering down equipment—especially the guidance computer, since its gyroscopes, which kept the platform steady, were heavy users of electricity and water. The guidance platform wouldn’t be needed until after the astronauts had rounded the moon, some fifteen hours later. Immediately, the GUIDO protested that he didn’t want to lose the platform alignment, which had been transferred so carefully from the command module. The TELMUS replied that before the next burn the astronauts could set up a new platform alignment with the spacecraft’s sextant by taking sightings on stars. The GUIDO wasn’t sure that this was possible; Deiterich, the RETRO, insisted that the platform be kept up all the way through the next burn, too; and, upstairs, Lunney, who often backed the pilots against the more conservative mechanics, agreed, although he permitted the F.D.A.I. balls—the dashboard display for the platform, which also used electricity—to be turned off.
This decision put Peters and Heselmeyer, the two TELMUs downstairs with the White Team, who had been working up what they called a “power profile” for rationing the LM’s electricity, in a tough spot. It was true that if all went well the trip home could take considerably less than four days; even so, the TELMUs had to think in terms of what they called “worst-case planning”—a conservative approach incumbent upon anyone rationing consumables. Even more than electricity, the supply of water for cooling the LM’s electronic gear was a source of worry to the TELMUs. There was a direct relationship between the two; the more electricity the instruments drew, the more water they needed, so cutting down on power consumption was a way of saving water. The cooling system worked like a car radiator, except that the water was not recycled; all the while the LM was powered up, water slowly steamed off into space, boiling away so gently that, as far as anyone could tell, it had never disturbed a trajectory.
Of all the TELMUs’ problems, however, the worst was not conserving a consumable but the reverse: how to get rid of the carbon dioxide that the astronauts were exhaling. Normally, the air in the cabin of either the LM or the command module was constantly passed through pellets of lithium hydroxide (small white pebbles that have an affinity for carbon dioxide and therefore remove it) in a process astronauts and flight controllers call “scrubbing the atmosphere.” The pellets were inside canisters that fitted into a sort of ventilating system that sucked dirty air from the cabin and then blew the scrubbed air back. When a canister had absorbed all the carbon dioxide it could hold, it had to be replaced with a fresh one. The trouble was that there weren’t enough canisters in the LM to last until the astronauts got home, the command module’s ventilating system was turned off, and the logical solution, which was to use the command module’s canisters in the lunar module’s air-purifying system, wouldn’t work, because they didn’t fit. The problem had never been considered in plans for “the lifeboat mode.” Now the TELMUs turned it over to another group, the Crew Systems Engineers, who were responsible for all such equipment, and who would have two days to solve the problem before the astronauts were asphyxiated.
Up in the spacecraft, the astronauts were worrying about their consumables. Haise feared that the cautiously optimistic reports from the TELMUs were a coverup for bad news. He kept double-checking the consumables to make sure that what he was being told was true. Like the TELMUs, the astronauts were most worried about their water supply, and, without telling the ground, Lovell decided that they would stringently ration what they drank. He set Swigert to work transferring some of the drinking water from a tank in the command module to the lunar module. The command module’s initially almost unlimited supply of water had stopped, of course, as soon as hydrogen and oxygen were no longer being combined in the fuel cells. Swigert had a hard time transferring the water, because the hose fittings in the two modules didn’t match—another curious design defect in
two craft built for mutual assistance. Swigert had to use plastic juice bags to make the transfer from the command module to the LM, and in doing so he sloshed water into his shoes. Later, the SPAN engineers would get the technicians at Hamilton Standard, in Connecticut, to look into the feasibility of using the astronauts’ backpacks—which have compartments for water—as pails. It would take two days for Swigert’s shoes to dry, because with so much equipment turned off the spacecraft was getting cold. He felt as if he were in a leaky boat. In fact, Swigert, who knew least about the lunar module, was the most worried of the three. He stood by a window in his wet shoes watching the earth recede behind them and had some very deep thoughts about never coming back.
Lovell’s and Haise’s many tasks didn’t give them much time for worrying. If they were to avoid the risk of having one part of the spacecraft become overheated by the sun, they had to regain control of its attitude and then set up the thermal roll. There were still occasional spurts of oxygen from the service module, but the venting was less disruptive now. Lovell took hold of the hand control for the attitude-control thruster jets, which in the LM was on the dashboard by his left hand. He ran into trouble right away, because the designers had never intended the lunar module to control the attitude of the entire Apollo spacecraft. The LM was at one end of the combined craft—a bad spot for handling the two other modules—and its thrusters were too weak to handle easily a mass more than twice its own.
As word of the disaster spread, many astronauts had come tumbling into the Control Center to see what they could do to help. One job they could perform was to man the simulators and test maneuvers that hadn’t been tried before. The lunar-module simulator was being run by Charles Duke, the backup LM pilot. The simulator, a replica of the LM’s cockpit, was hooked up to the smallest of the five computers in the R.T.C.C, and technicians there had already programmed it with data about the present situation, such, as the strength and position of the LM’s thrusters in relation to the rest of the spacecraft, and even the random effects of the venting. Duke experimented to see if the LM could wrestle the entire spacecraft more easily by firing its thrusters steadily or in short bursts. Short bursts worked better, and this information was passed on to Lovell.
There was no guarantee that the simulator reproduced the motions of the spacecraft accurately, and, indeed, Lovell was finding he couldn’t regain control nearly as easily as Duke had done. Because the F.D.A.I. balls had been turned off, Lovell was without a compass, and the only way he could maneuver was by referring to three separate gauges on the dashboard which gave him the angles of roll, pitch, and yaw; it was about as chancy as lining up the three Bell-Fruit bells in a slot machine. Moreover, he was becoming so fatigued that he couldn’t remember whether he should fight the spin by going left or by going right, and once he found himself turning entirely around. To add to his problems, he had been having trouble with communications ever since he had begun using the radio in the LM; it made a continual beeping sound, so that he and the flight controllers could barely hear each other. The trouble was caused by a radio transmitter aboard the third stage of the Saturn rocket that had launched the spacecraft and was now trailing a thousand miles behind it on the way to impact on the moon. The transmitter aboard the rocket booster was beeping so that it could be tracked from the ground, and it was using exactly the same frequency as the LM’s own radio. This arrangement saved money on ground equipment, and NASA justified it by pointing out that the astronauts weren’t supposed to be flying the LM until after the booster had crashed into the moon. On one occasion, Haise told the CAPCOM that he could barely hear him, and the CAPCOM radioed up some emergency instructions for getting home in case communications were lost altogether. Fortunately, the INCO remembered a trick that cut down on the interference. He got the astronauts to turn off their radio for twenty minutes, and during that interval he broadcast a steady signal to the booster on a slightly different frequency, causing its transmitter to shift frequencies. This incident was not the only one in which flight controllers had to play tricks on the overconfidently designed equipment.
Just before dawn in Houston, the spacecraft’s attitude suddenly took a turn for the better. By using the jets the LM normally employs for translation—a way of moving the craft up, down, and sideways rather than turning it—Lovell finally managed to get it stabilized and pointed in the right direction—sideways to its trajectory and perpendicular to a plane drawn through the earth, moon, and sun. (Duke in the simulator had been the one to discover that the translation jets were more efficient for jockeying the entire spacecraft.) The next step was to set the spacecraft rolling, for thermal protection, and to keep it rolling—something that the LM’s guidance system was not equipped to do, as a LM did not need to roll on its short hop to the moon. Duke had been working on this problem in the simulator, too, and now the CAPCOM radioed up that Lovell would have to rotate the spacecraft some ninety degrees every hour by hand. The CAPCOM promised to remind him to do this.
Around four in the morning, Lovell sent Haise back to his couch in the command module to get some sleep. The command module, which the astronauts had taken to calling “upstairs,” would be the bedroom for the rest of the trip. Haise had last looked at his wristwatch before the accident, seven hours earlier, and he had lost all track of time. For him, the intervening period—in which he and the others were abruptly confronted with an almost insoluble problem in a strange place—had had a dreamlike quality.
At about eight o’clock in the morning, after Kranz and the White Team had also gone off to get some sleep, some forty men gathered in the glass-enclosed gallery for visitors, at the back of the third-floor Control Room. They included Robert R. Gilruth, the Director of the Manned Spacecraft Center; his deputy, Christopher C. Kraft, Jr.; and James A. McDivitt, the Apollo Spacecraft Program Manager. Occasionally, the flight controllers of the Gold Team, which had taken over from the Black Team an hour earlier, glanced over their shoulders to see what was going on. A FIDO who happened by said later that he had never before seen so much NASA brass in one place at one time. The NASA brass was trying to decide which of three possible types of burn to do after the astronauts had rounded the moon. The burn was scheduled for eight-thirty that evening, which would be two hours after pericynthion—the spacecraft’s closest approach to the back side of the moon—and hence it was called the PC+2 burn. Pericynthion was the point at which the service-module rocket was normally fired to put a spacecraft into lunar orbit, and, in the event that that rocket failed, the point two hours past pericynthion had always been considered the place to do an emergency burn back to earth, because it ordinarily took two hours to power up the LM rocket. (It was the emergency checklist for this burn that the flight controllers had cribbed from the night before to power up the LM.)
Christopher Kraft, who before he became Deputy Director of the Manned Spacecraft Center had once had Kranz’s job as Chief of the Flight Control Division, outlined the alternative burns that could be made at PC+2. The first was to jettison the service module and blast the LM’s rocket with everything it had, so that the astronauts would arrive in the Atlantic Ocean a day and a half afterward. Nobody liked this idea any better than Kranz’s group had liked a similar proposal the night before. It left virtually no room for error—and out around the moon an error in velocity of a tenth of a foot a second could cause a spacecraft to miss the earth altogether. The reason the RETROs had always achieved astonishing accuracy in splashdowns from the moon was that they could, as they put it, “tweak up” a trajectory anywhere along the line with midcourse corrections, and the fast burn to the Atlantic would leave little fuel for tweaking. Besides, in the Atlantic there were no recovery ships.
Kraft hurried on to the two other alternatives, either of which would avert the emergency landing in the Indian Ocean, where the spacecraft was now headed, and bring the astronauts to the prime landing area in the southwest Pacific—the only spot on earth where there were adequate recovery vessels. One of these alte
rnatives involved a relatively fast burn, which would get the astronauts to the Pacific about a day and a half afterward, and the other involved a slower burn, which would get them there exactly twenty-four hours later than that. The twenty-four-hour difference had to do with the earth’s rotation—the spacecraft always descended to its splashdown from perigee, the closest approach on the side of the earth that was away from the moon, and consequently the splashdown point depended on the time the spacecraft reached perigee. (The RETROs like to say, “Don’t worry—the Pacific will be there!”)
While Kraft spoke, those listening to him could see through the glass behind him the big center screen at the front of the Control Room, where the yellow line representing the trajectory of the Apollo spacecraft was moving closer and closer to the moon. From time to time, they glanced at Dr. Gilruth, the Director of the Manned Spacecraft Center, who had previously been director of the Mercury project, the first American manned-spaceflight program. He was the senior man present, and when NASA people met to make a decision there was no voting; rather, after discussion the top man made the decision.
Kraft threw the meeting open for discussion. The faster of the two burns to the Pacific had an immediate appeal, for everyone shared the fear that something else might go wrong with the spacecraft, in which case the sooner the astronauts got home the better; indeed, this seemed such an obvious choice that some astronauts were already practicing it in the simulators. The fast burn to the Pacific had one serious drawback, however: just as in the case of the even faster burn to the Atlantic, the astronauts would first have to jettison the service module, because the LM was strong enough only to push itself and the command module to the required velocity. Flight engineers have a natural reluctance to do anything as irrevocable as throwing away one third of a spacecraft. Most important, the service module, fitting snugly over the heat shield—the ceramic bottom of the command module, designed to protect the astronauts from the heat of reëntry through the earth’s atmosphere—insulated the shield, and no one knew what effect a prolonged exposure to the cold of space would have on it. The service module was normally jettisoned only half an hour before splashdown, and no one had thought it necessary to test the heat shield’s resistance to cold for the length of time it would take a spacecraft to come back from the moon.
Thirteen: The Apollo Flight That Failed Page 6