Apollo: The Race to the Moon (66 page)

At 7:13 Tuesday morning, ten hours after coming on duty, Glynn Lunney’s Black Team turned their consoles over to Gerry Griffin’s Gold Team. Though there had been many other memorable shifts in that room—Gene Kranz’s White Team had just finished one of them the preceding evening—no flight control team had ever been asked to make so many life-and-death decisions, find so many improvised fixes, and sustain their nerve for so long. Glynn Lunney’s Black Team left the MOCR still unsure whether they had saved the crew of Thirteen. They had at least preserved them.

Chapter 29. “I hope the guys who thought this up knew what they were doing”

The first time anyone had ever thought about using a lunar landing craft as a lifeboat was in 1961, even before the L.O.R. decision had been made. Two of Grumman’s designers, Tom Kelly and Al Munier, were in the preliminary phases of the design when Munier had a thought. Suppose something happened on the way out to the moon, Kelly remembered him musing. Could this little machine they were designing bring the command module back? Kelly and Munier worked through a few calculations. “Nothing had been built yet,” Kelly recalled, “so changing the specifications really didn’t cost anything.” Planning for the lifeboat option “gave you more fuel to land [on the moon] with, it let you stay on the moon a little bit longer, and it gave you a rescue option.” In writing up the specs, Grumman increased some of the quantities on the consumables, and Kelly kept the lifeboat idea in the back of his mind.

In 1963, the possibility of using the LEM as a lifeboat came up at North American in the course of building the command module. North American inquired of NASA whether the LEM would have a thrusting capability sufficient to maneuver it with the command module attached. This intrigued Bob Piland, then acting head of ASPO, who responded with a request that North American look into the possibility of using the LEM to provide a backup in case the S.P.S. failed in translunar flight. Eventually it was determined that the LEM could function as the source of engine power for a combined LEM and C.S.M. and, if necessary, push a crippled command module out of lunar orbit and back home.

In the Flight Operations Directorate, the lifeboat option had come up in various forms. Glynn Lunney remembered that when he was head of the Flight Dynamics Branch in the early 1960s, his guys had started to talk about a lifeboat procedure. It wasn’t part of a systematic strategy, Lunney recalled; just another example of their “try-everything way”—“Hey, you know, we’ve got another engine on the LEM, we ought to know how to use the LEM engine [for docked burns]. We don’t know what for, but who knows?” They worked out some procedures and filed them away. The EECOMs had gotten some practice in lifeboat procedures as well. Once during a simulation of lunar orbit, a glitch in the cabin pressure showed up on the EECOM’s screen just before loss of signal as the spacecraft went around. The EECOM didn’t take the hint. When the command module came back around into radio contact twenty minutes later, the flight control team abruptly discovered that the spacecraft cabin pressure had gone to zero and the astronauts were already buttoned up in their suits to stay alive. The flight controllers used the LEM’s oxygen supply to repressurize the C.S.M.

The White Team in particular had gotten some relevant lifeboat experience out of Apollo 9. During an Apollo 9 simulation of “mini-maxi double-bubble rendezvous,” which involved a wide separation between the LEM and C.S.M., the SimSup failed the LEM engines, forcing the crew and the flight control team to conduct a rescue in which the command module maneuvered into a rendezvous with the LEM instead of the other way around. Since the orbital characteristics of the two craft meant that the rescue would require thirty hours, and the LEM for Apollo 9 was only an eighteen-hour spacecraft, the White Team had to work out procedures to keep the LEM’s astronauts alive. During the Apollo 9 flight itself, the White Team gained another useful bit of experience when the lunar module conducted DPS burns with the command module attached, to test the ability of the LEM to control both spacecraft.

Such experiences led to a few procedures that could be pulled off the shelf during Apollo 13. Still, the flight control team had never developed procedures for an accident of the magnitude of Thirteen’s. They had imagined losing one of the two oxygen tanks, or a battery, or even the S.P.S. engine. But never had the simulations postulated that the C.S.M. would be completely dead. Surely, everything thought, anything that knocked out both oxygen tanks would also destroy the spacecraft. Apollo 13 brought a change in simulation policy. FIDO Dave Reed summarized the new ground rule: “They can throw anything at us they want and we won’t object.”

The problem that preoccupied the MER and the contractors from the time of the accident through the rest of the mission was whether Aquarius had enough oxygen, water and electricity to sustain life until Apollo 13 could get home. It was known as “the consumables problem.”

Aquarius had been designed to take Lovell and Haise to the lunar surface (less than five hours), remain there for another thirty-three hours, then rendezvous with the command module (about two hours), and still have a five-hour reserve—a lifetime of forty-five hours. Counting from the time the LEM was activated during Apollo 13, the return could take as little as seventy-seven hours or as much as a hundred, depending on what kind of additional burns were decided upon. The numbers were painfully discrepant. Aquarius had to be operated so that its water, oxygen, and electricity would last at least 70 percent longer than intended, and perhaps more than twice as long. The specialists on the LEM quickly came to a few basic conclusions.

Oxygen was not a problem. To support a lunar landing, the LEM was designed on the assumption that its door would be opened when the astronauts went outside for their E.V.A., venting all of the cabin’s oxygen. For Apollo 13, two E.V.A.s had been planned, meaning that the LEM had to carry enough oxygen to repressurize the cabin twice, plus provide enough oxygen for the time that the crew was in the cabin. With that much plus the safety margin built into the system, Aquarius had plenty of oxygen for the trip home even with all three astronauts drawing on it. Because the LEM used batteries instead of fuel cells, oxygen didn’t figure in the calculations about power supply.

In contrast, water was a huge problem. The electronics in the spacecraft generated heat that was carried off by glycol circulating through the systems. The warmed glycol was recooled by running it through tubes encased in ice. The ice was made by the cold of space from water supplied by the LEM. As the glycol ran through the pipes, the ice vaporized and boiled away. Every system that remained powered up used water.

Aquarius carried 338 pounds of water in its tanks. During the first hours after the crew moved in, the LEM was consuming water at the rate of 6.3 pounds per hour. Arithmetic immediately revealed that, at that rate of consumption, Aquarius would have no water at all after fifty-four more hours—twenty-three fewer hours than the fastest possible return to earth. The astronauts would survive without water for the extra twenty-three hours, but the equipment wouldn’t.

Electrical power was also in short supply. The descent stage of Aquarius had four batteries; the ascent stage had two. From the six batteries together, and after subtracting the power that had already been expended in checking out the LEM, the planners on the ground could count on fewer than 2,000 amp-hours of electricity. Ordinarily, the LEM used fifty amps. Two thousand divided by fifty gave only forty hours. Moreover, they were going to be making extraordinary demands on Aquarius. As the men in the MER and at Bethpage calculated the maneuvers Aquarius would have to make and the power it would take from the LEM to power up the partially depleted entry batteries in Odyssey, it was decided that Aquarius would somehow have to use a maximum of 15 amps when it was not maneuvering. Until the day of the accident, the LEM’s designers had calculated that the LEM’s minimal configuration used 20 amps.

To conserve water and power, the engineers in the MER went systematically through the spacecraft, looking at every component to see whether it could be turned off completely. If not, they calculated the lowest voltage at which any given piece of equipment would operate and the minimal configuration in which a system would continue to perform the functions it absolutely had to perform. Forget the specs, forget the rulebooks, forget the operations manuals, Arabian announced. Go back to the physics of the design that no one knows better than you, the knowledge that’s not written down anywhere, and decide what’s the least we can really get away with.

For example, the DPS engine contained an Abort Sensor Assembly (A.S.A.) that monitored its performance. The A.S.A. included small heaters that kept it at seventy degrees Fahrenheit. What would happen if the heaters were turned down so that the fluid in the A.S.A.’s gyroscopes was maintained at a few degrees above freezing? Would the A.S.A. still work? There was no time for anyone in the MER or at Grumman to conduct tests; the answer had to be provided on the basis of the inadequate data at hand. In the case of the A.S.A., the engineers decided that it should be able to function under those near-freezing conditions, and so the crew was told to turn the heaters down. Everyone hoped for the best.

As such questions spread through the support network, often ending in the laps of the people who had originally designed the equipment, cautious engineers were faced with a choice between two incompatible demands. Each was sensitive to the critical nature of his own piece of the puzzle (for example, it could be disastrous if the A.S.A. failed to detect a malfunction in the DPS during the next burn). The temptation to insist that his piece of equipment be operated within the tolerances for which it had been designed was powerful. And yet each also understood that somehow the voltages and the heat sources in the lunar module had to be cut drastically. Small dramas were played out all over the country as designers passed on the word, usually with too little data to be sure they were right, that their babies would continue to function under the unprecedented conditions that Houston was proposing. This process of redefining the LEM’s capability continued throughout the flight, as the reserves dwindled and the conditions within the spacecraft kept changing. Years later, John Strakosch, a Grumman engineer at Bethpage, would say it was the most intensely concentrated work he’d ever done—an effort that in his memory seemed to last eighteen or twenty hours. His handwritten log of his activities reveals that it lasted for what amounted to three unbroken days.

Bit by bit, the LEM was powered down to fifteen amps, and the astronauts, wearing thin clothing designed for a long trip in a confined space at seventy degrees, began to get cold as the temperature dropped below sixty degrees and kept going down.

In the process of inventorying the consumables during the first night, someone discovered that, as things stood, the astronauts would asphyxiate from carbon dioxide buildup before they got home. In both the LEM and the command module, carbon dioxide was removed by circulating the air through canisters of lithium hydroxide. The problem was that Aquarius had only two such canisters, not nearly enough to last the journey home. Odyssey had plenty of canisters, but they were the wrong size and shape to fit the LEM’s equipment. The problem was passed along to the Crew Systems Division: Figure out some way to use the C.S.M.’s lithium hydroxide canisters in the LEM. Unless they came up with an answer, none of the rest of the planning was going to make any difference.

At 8:00 on Tuesday morning, less than twelve hours after the explosion, a meeting of NASA’s most senior managers, from the Houston directorate chiefs up through Administrator Thomas Paine, convened in the viewing room behind the third-floor MOCR. Gerry Griffin’s Gold Team was now on shift, its members occasionally looking back curiously at the all-star assemblage behind the glass.

Chris Kraft led the discussion. The question before the group was how quickly to bring the crew back. It had already been decided to conduct the next burn at two hours after pericynthion (the spacecraft’s closest approach to the back of the moon), making it known as the P.C.+2 burn.

Kraft explained their three options. They could, if they chose, bring the crew back in less than thirty-six hours after P.C.+2 with a long burn at full throttle if they were willing to bring Odyssey down in the Atlantic where NASA had no recovery ships. Kraft didn’t spend much time on this option, for it was only a few hours faster than the second one, thereafter called the “fast burn,” which would put the spacecraft in the southwest Pacific, the prime recovery area, in less than thirty-nine hours. The third option was a shorter, lower-power burn (the “slow burn”) that would return the spacecraft to the prime recovery area in sixty-three hours, or twenty-four hours later than the fast burn. They had no intermediate choices if they wanted to land in the prime recovery area. A spacecraft returning from the moon had limited maneuvering range. If one wanted to put the space in a particular spot along the potential landing track, it was available only once per earth rotation.

Given the concern about the consumables and the risks inherent in keeping the crew in a disabled spacecraft any longer than necessary, the case for the fast burn seemed so compelling that the astronauts over in Building 5 were already practicing it. However, Kraft wanted the slow burn even at the cost of the extra twenty-four hours. So did his lead Retro and his lead FIDO, Chuck Deiterich and Dave Reed respectively. Kraft called the two of them into the viewing room so that the others could hear why firsthand.

The fast burn would take virtually all the propellants that the LEM had, they explained, with little energy left for tweaking the trajectory if it were in error. It didn’t take much of an error in the burn to make tweaking necessary—at 240,000 miles away, an error of a tenth of a foot per second in a burn could compound in such a way that the spacecraft would miss the earth altogether.

The fast burn also required that the heavy service module be discarded beforehand. “They don’t have a rearview mirror on that spacecraft,” Reed pointed out. “We don’t know what’s happened back there.” Why take the damaged service module off any sooner than they had to? More important, the service module covered Odyssey’s heat shield and protected it from direct exposure to the heat (on the sun side) and cold (on the shadow side) of outer space. No one had ever tested what would happen to the heat shield if it were exposed to the thermal conditions of outer space for forty hours before it had to work. No one knew how much effect it would have on letting heat out of, or cold into, the command module itself. Deiterich and Reed didn’t want to use Apollo 13 to find out.