As is bound to happen on any ship with a bad leak, a certain amount of confusion arose. Once, the astronauts turned off a switch that incidentally cut out the gauges for the oxygen tanks; Liebergot quickly got them to turn it back on again. Another time, they failed to turn off a part of the guidance system that the ground had asked them to switch off, and no one discovered the omission until the spacecraft began jerking about. Consequently, Kranz requested the astronauts to read back to the ground the dials of all the two hundred and fifty instrument gauges on two of their dashboard panels, for it was imperative that the flight controllers who would be figuring out how to bring the dead command module back through the atmosphere know exactly what the situation was. The astronauts began their reading-back at 9:59 P.M., and it went on for ten minutes.
As additional precautions, Kranz requested that a two-hundred-foot radio antenna (called a deep-space dish) in Australia be added to the global network tracking and communicating with the spacecraft, and that additional computers at the Goddard Space Flight Center in Maryland be what he called “cranked up”—made ready for use. He also telephoned the Real Time Computer Complex on the ground floor of the Operations Wing to ask that an additional big I.B.M. computer be brought onto the line. The computer complex gets its name from the fact that it processes data in “real time,” the flight controllers’ term for instantaneously. And since the average Apollo flight transmits fifty-five million bits of data, this takes some doing. Most NASA engineers believe that it was the United States’ superiority in computers, more than anything else, that gave this country the ability to land men on the moon when it did. The figuring for the first Soviet manned orbital flights may well have been done by teams of men using desk calculators. The technicians in the R.T.C.C. have consoles much like the ones in the Control Room upstairs, and, indeed, many of the computer technicians are the counterparts of—or, as they put it, they “interface with”—the flight controllers. (The interfacing is done over an intercom.) Through a glass partition, the technicians overlook a brightly lit room filled with computers; each computer consists of a couple of dozen cabinets arranged in a rectangle, like refrigerators in a showroom, and, like refrigerators, they need to be kept cool for maximum efficiency. There are four big computers, each capable of handling a flight to the moon, and a fifth, smaller one, used for simulations.
During the non-critical periods of a lunar mission—the sleep periods and the trans-lunar and trans-earth coasts—all the work was ordinarily done by just one computer, designated the Mission Operations Computer, while a second, designated the Dynamic Standby Computer, was hooked up during critical periods—launch, moon-landing, and reëntry—and served as a backup, receiving all the telemetry information from the spacecraft that the main computer was getting, in case it suddenly had to take over the running of the mission. On the night of the accident, the standby computer was of course receiving no data from the spacecraft. In fact, like the third and fourth big computers in the room, it had been farmed out for totally unrelated work, because NASA was having budgetary problems and computer time is very expensive. After all, there had been only a few times in the past when anything had gone wrong with the primary computer necessitating a switch to the backup, and, besides, if an emergency should arise, the primary computer could load all the data about the flight into the backup in twenty milliseconds, which was a very short time indeed. Of course, if the primary computer was incapacitated, it might not be able to load the backup at all. Now Kranz wanted to rectify the situation; he had had enough trouble with backups that night.
As Kranz and Liebergot went about their preparations for the worst, they clung to their faith in the spacecraft’s recuperative powers. Kranz said later, “We were still hoping to come up with the right configuration of tanks, fuel cells, and buses, and fly out of the woods with the oxygen in Tank No. 1.” He held on to this hope in spite of the fact that the pressure in the tank had dropped from nine hundred pounds per square inch, which was normal, to only three hundred. Liebergot at last recommended that the heaters and the fans for Tank No. 1 be turned on, so that the heat could increase the pressure and the flow of oxygen into the fuel cell. Liebergot studied his telemetry screen. He saw a sudden jump in the amount of current leaving the good bus, and knew that the fans and heaters were on. He did not, however, see any compensating jump in the oxygen pressure; in fact, it was continuing to drop at about the same rate. If anything, the drop was a little faster; the heat almost certainly accelerated the leak. As he watched, the pressure dropped three pounds per square inch, and this made Liebergot pessimistic once more. He said to Kranz, “You’d better think about getting into the lunar module and using the LM systems.”
Forty-seven minutes had passed since the accident. Kranz now turned his attention to the lunar module. He told Heselmeyer, the TELMU, to get some men started figuring out the minimum power-up of the LM needed to sustain life. Kranz wasn’t yet through with the command module, however. He asked Liebergot if he had any more suggestions for restoring the oxygen pressure. Liebergot had not, but he canvassed some of his assistants—each of the flight controllers was backed up by a team of experts in the Staff Support Rooms, just outside the Control Room—and one of them came up with the idea that the oxygen leak might not be in the tanks at all but, rather, in one of the fuel cells. Fuel Cell 3 seemed like a good candidate, since it had been the first to fail. Liebergot immediately called Kranz and suggested that the astronauts close that cell’s reactant valve, and so cut it off from the tanks. If the assistant was right, the leak would stop. It was the last hope for a simple way out. The reason nobody had suggested shutting the reactant valve earlier was that it was an irreversible act: the fuel cell would be permanently out of service, and there would be no possibility of landing on the moon. Kranz had at last stopped thinking about a lunar landing. However, Haise, on whose side of the spacecraft the reactant-valve switches were, had no intention of taking an irrevocable step that would abort a four-hundred-million-dollar mission all by himself—his own pessimistic evaluation of the situation to the contrary—and, accordingly, he asked the CAPCOM to repeat the order, to make sure there was no mistake. It would have saved him some uncertain moments if he had known the valve was already shut—and had been since the bang—but then nobody knew that. Liebergot gazed at his electronic screen to see what effect isolating the fuel cell would have on the oxygen leak. It would take a while to find out. In fact, it took longer than he expected, because Haise, reluctant to perform this irrevocable act, had to be given the instruction a third time before he flicked the switch for the valve. After an interval, Liebergot was able to determine that the oxygen was still going down at the same rate. At last, Kranz and Liebergot were face to face with the possibility that they were dealing not with a leak but with some sort of explosion that had knocked out the entire oxygen system. At last, they were compelled to accept the fact they had resisted for so long—that their main craft’s redundancy had failed them. Fortunately, that craft was better prepared than most sinking vessels. NASA had provided it with the ultimate in redundancy—a whole other craft.
Some time later, when Kranz was asked whether he had ever feared for the lives of the astronauts, he replied, “Yes and no.” Then he added, “I guess the answer is no, because I have worked with the lunar module more than any other Flight Director. I had the utmost confidence in the LM and in the flight controllers. I knew that the life-support system was good, the communications were good, and the guidance system was good, and that it could make long rocket burns. I was sure it would prove to be a reliable spacecraft.”
Once again, Kranz was more confident than his flight controllers, for Heselmeyer, who, as TELMU, was in charge of the LM’s electrical and environmental system, was not at all sure that the LM, which was designed to support two men for about two days, had enough consumables to support all three astronauts during the entire journey back to earth. “Consumables” was NASA’s term for the fuel, water, and power that the spac
ecraft consumed and the oxygen and water that the astronauts consumed. A less euphemistic term might have been “essentials.” It looked as though the TELMU was going to have to make the LM’s consumables last three men for four days, because the Retrofire Officer, Bobby Spencer, who was in charge of emergency-return plans, and who had sent Kranz the note just before the accident that the spacecraft was close to the point where it could no longer return directly to earth, was talking now more and more in terms of going home around the moon. In the interval since he had sent the note, the spacecraft had travelled about three thousand miles. The moon was now only forty-five thousand miles away, and the earth five times that distance behind the spacecraft. When the spacecraft left the earth, it had been travelling at about twenty thousand miles an hour, to escape the planet’s gravity, but as it rose higher above the earth its speed slowed—like that of a tossed-up ball near the top of its rise—to a little over two thousand miles an hour. Now it was about to pick up speed again as it fell toward the moon. If the direction couldn’t be reversed, the TELMU was going to have to stretch the LM’s human consumables threefold and its power twofold.
Like everyone else at NASA, those who were concerned with the LM’s consumables had never dreamed that a command module would go completely dead, let alone do so at the point where it had the farthest possible distance to travel back to earth. (The only worse time for the accident to have occurred would have been when the astronauts were on the moon, in which case the command module would have been without its lifeboat.) One flight controller later made much the same observation as Swigert: “This particular situation was so far down the line that it was exceedingly unlikely, and if anyone had asked us to simulate it ahead of time we would all have said he was being unrealistic.” For much the same reason, there hadn’t been enough lifeboats aboard the Titanic, and the passengers had had no boat drill and so didn’t know how to use them. NASA engineers had been relying for some time on the fact that they could use the LM as a lifeboat in an emergency, but they had not paid much attention to what they called “the lifeboat mode.” The few simulations of such a problem they had run had been short-term affairs, because they had always assumed that if anything should happen to the command module the astronauts could repair it and be back inside it in a few hours. Aside from some tests a year earlier at the time of Apollo 9, which didn’t quite cover the present situation, no one had ever experimented to see how long the LM could keep men alive—the first thing one needs to know about a lifeboat.
In fact, the lifeboat mode was considered such an unlikely eventuality that ordinarily during the long coast to the moon, when the lunar module was inactive, the LM’s consoles in the Control Room were not manned. By a lucky chance, a TELMU—Heselmeyer—happened to be present at the time of the bang (he had come in to supervise what was known as a “LM housekeeping”), and a few minutes later Kranz had come on the loop to say that he wanted the LM consoles manned around the clock from then on. Heselmeyer’s initial estimate of the LM’s consumables was so chilling that he called the RETRO and tried to talk him into doing a direct abort—aiming the spacecraft toward the earth and blasting home with the big rocket in the service module. Theoretically, it could still be done. A direct abort could take as little as a day and a half, which would be much better from the TELMU’s point of view than a trip around the moon, which he estimated would take about four days.
This conversation took place over a secondary loop—one of several telephone hookups that the flight controllers could talk on among themselves without interrupting the main loop of the Flight Director. The Retrofire Officers were not happy about the TELMU’s request. There were two RETROs now, for Spencer, the one on duty, had been joined by the Lead Retrofire Officer, Charles Deiterich, who would have the chief responsibility for planning the route back. Deiterich—a tall, laconic man with a droopy mustache, who was a graduate of the University of St. Thomas in Houston and had joined NASA in 1964—told Heselmeyer that at the moment the spacecraft was so close to the moon’s gravitational pull that in order to blast the command module straight home the lunar module would have to be jettisoned, because the main rocket was not strong enough to reverse the direction of the entire spacecraft. Liebergot, who was listening in on this conversation, now said that he could not approve any plan that meant getting rid of the LM. Deiterich added another argument against the direct abort: the spacecraft was getting very close to the point at which a maximum burn of the main service-module rocket not only wouldn’t reverse the spacecraft’s direction but would simply slow it so that it crashed into the moon. And—assuming that point hadn’t been reached quite yet—if for any reason the big rocket couldn’t be brought up to full thrust, the spacecraft would crash into the moon anyway. As Deiterich listened to the conversation from the spacecraft, he wondered if the rocket could be fired at all, in view of the electrical failure. Heselmeyer went back to considering ways of stretching the LM’s consumables over the estimated four days. To get some help, he put in a call to the Spacecraft Analysis Team (SPAN), a group of engineers in a nearby Staff Support Room who were in constant touch with the prime contractors of the spacecraft—for the LM, the Grumman Aerospace Corporation in Bethpage, New York, and for the command and service modules the North American Rockwell Corporation in Downey, California. At Grumman and North American, there were subsidiary SPAN groups in touch with a number of subcontractors; Heselmeyer’s questions were referred to, among others, technicians at the Hamilton Standard Division of the United Aircraft Corporation at Windsor Locks, Connecticut, the subcontractor for the LM’s environmental-control subsystem. (Through this cross-country network, the SPAN engineers would get the flight controllers answers to about a hundred and fifty questions; the wires were already humming between the SPAN room in Houston, the SPAN room at North American, and one in Boulder, Colorado, at the Beech Aircraft Corporation, the subcontractor for the hydrogen and oxygen tanks in the service module.)
Before altogether ruling out the direct abort, Deiterich got the technicians downstairs in the R.T.C.C. to run several possible direct-abort trajectories through their computers, and he passed on a list of seven potential landing sites to the Recovery Operation Team, which was in charge of picking up the astronauts when they splashed down. The Recovery Officers, who were in a glassed-off room to the right rear of the Control Room, were even worse prepared for the emergency than the TELMUS. Because of the success of previous spaceflights, NASA had felt justified in gradually lessening the number of rescue ships. During the Mercury and Gemini programs, when astronauts were orbiting the earth, there had been twelve or so recovery ships stationed around the world at such intervals that no matter where the spacecraft came down there would be a ship within a few hundred miles. However, as spacecraft began going all the way to the moon the number of ships had been reduced, on the theory that in the event of trouble there was more chance to guide a spacecraft to a specific landing site, fewer degrees of latitude on which to spread out the ships, and more time to dispatch a recovery force to meet it; airplanes could drop frogmen to open the capsule’s hatch at any point on earth in a matter of hours. No one seriously believed that a crippled spacecraft falling from the moon might need more than frogmen to meet it. By the time Apollo 11 made the first landing on the moon, the number of recovery sites had been cut down to four—what Recovery Officers called the Mid-Pacific Line, the West-Pacific Line, the Atlantic Ocean Line, and the Indian Ocean Line. By the time of Apollo 13, all four of these stations still existed in the minds of Recovery Officers, but only one of them, the Mid-Pacific Line, had any ships at it. When the Recovery Officers were told that they might have to have a rescue force at any one of seven places within as little as thirty-six hours, they swung into action. First, they called the Department of Defense to see if any United States Navy recovery ships happened to be near any of the targets; they also surveyed merchant shipping around the world for what they called “ships of opportunity”—a hair-raising idea at NASA, where nothing is
supposed to be left to chance. Twelve countries volunteered ships. The nearest ship of opportunity to the Atlantic Ocean Line turned out to be a carrier, the U.S.S. America, which had just left Puerto Rico and couldn’t get to the site until twenty-four hours after a splashdown there.
An hour and nine minutes after the bang, the White Team handed over control of the spacecraft to the Black Team. Some minutes before this, Kranz had announced over the loop that the TELMUs and Recovery Officers who were working on plans for a direct abort back to earth could forget it—they did not know what shape the main rocket in the service module was in, and they had more confidence in the LM’s main rocket, the Descent Propulsion System. The spacecraft would be going around the moon. There was relief in the Recovery Room, if nowhere else.
Thirteen: The Apollo Flight That Failed Page 4