Apollo 13: We have a solution

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This is a 3 part article written about the trouble shooting the engineers were doing on the ground behind the scenes of the Apollo 13 flight. Posted from:  http://www.spectrum.ieee.org/apr05/2697


Apollo 13, We Have a Solution
By Stephen Cass

Rather than hurried improvisation, saving the crew of Apollo 13 took years of preparation

13 April 2005—"Houston, we've had a problem."

Thirty-five years ago today, these words marked the start of a crisis that nearly killed three astronauts in outer space. In the four days that followed, the world was transfixed as the crew of Apollo 13—Jim Lovell, Fred Haise, and Jack Swigert—fought cold, fatigue, and uncertainty to bring their crippled spacecraft home.

But the crew had an angel on their shoulders—in fact thousands of them—in the form of the flight controllers of NASA's mission control and supporting engineers scattered across the United States.

To the outsider, it looked like a stream of engineering miracles was being pulled out of some magician's hat as mission control identified, diagnosed, and worked around life-threatening problem after life-threatening problem on the long road back to Earth.

From the navigation of a badly damaged spacecraft to impending carbon dioxide poisoning, NASA's ground team worked around the clock to give the Apollo 13 astronauts a fighting chance. But what was going on behind the doors of the Manned Spacecraft Center in Houston—now Lyndon B. Johnson Space Center—wasn't a trick, or even a case of engineers on an incredible lucky streak. It was the manifestation of years of training, teamwork, discipline, and foresight that to this day serves as a perfect example of how to do high-risk endeavors right.

Many people are familiar with Apollo 13, thanks to the 1995 Ron Howard movie of the same name. But as Howard himself was quick to point out when the movie was released, it is a dramatization, not a documentary, and many of the elements that mark the difference between Hollywood and real life are omitted or altered. For this 35th anniversary of Apollo 13, IEEE Spectrum spoke to some of the key figures in mission control to get the real story of how they saved the day.

First, A Little Refresher on moon-shot hardware: a powerful, 85-meter tall, three-stage Saturn V booster launched each mission from Cape Canaveral in Florida [see photo, To The Moon]. Atop the Saturn V rode the Apollo stack, which was composed of two spacecraft: a three-person mother ship to go to the moon and back, called the command and service module, or CSM; and a two-person lander, called the lunar module, or LM, to travel between the CSM and the surface of the moon.


 The two spacecraft each, in turn, had two parts. The CSM divided into a cylindrical service module (SM) and a conical command module (CM). The service module housed the main engine and supplied all the oxygen, electricity, and water the crew needed for the long voyage—it took about six days for a round trip between the Earth and the moon. The crew lived in the cramped command module, which housed the flight computer and navigation equipment. The command module was the only part of the Apollo stack that was designed to come back safely to Earth. It would plummet through the atmosphere, the blunt end of its cone designed to withstand the immense heat generated by the descent, and then deploy parachutes and splash down in the ocean.

The lunar module consisted of an ascent stage and a descent stage. The descent stage had a powerful engine used to land the lunar module on the moon. After the lunar expedition was complete, it served as a launch pad for the ascent stage, which housed the astronauts, to blast off and rendezvous with the command and service module in lunar orbit.

For most of the way to the moon, the command and service module and the lunar module—dubbed the Odyssey and Aquarius, respectively, on the Apollo 13 mission—were docked nose to nose. But the astronauts generally remained in the command module, because the lunar module was turned off to preserve power.

Most of that power came from a cluster of three fuel cells in the service module. The fuel cells were fed hydrogen and oxygen from two pairs of cryogenic tanks, combining them to produce electricity and water [see diagram, Module Map].



Module Map:: A cutaway diagram of the service module. The fuel cells, in green, provided water and electricity by combining oxygen and hydrogen stored in cryogenic tanks, marked in red and blue respectively. Oxygen tank 2, bright red, exploded during the Apollo 13 mission, almost killing the crew.

There were some batteries on board the command module, but these were intended for only a few hours use during re-entry, after the service module was jettisoned close to Earth.

It was one of the cryogenic tanks that would reveal itself as the Odyssey's Achilles' heel. On 13 April 1970, around 9 p.m. Houston time, almost 56 hours into Apollo 13's flight, mission control [see photo, Calm Before The Storm] asked the crew to turn on fans in all the cryogenic tanks to stir the contents in order to get accurate quantity readings. Due to a series of pre-launch mishaps, turning on the fan sparked a short circuit between exposed wires within oxygen tank two [see sidebar,  "The Devil's in the Details"The Devil's in the details

 The Odyssey was dying, but no one knew it yet.

Even The Crew were unaware of the gravity of the situation. In the Ron Howard movie, the oxygen tank two explosion is accompanied by a whole series of bangs and creaks while the astronauts are tossed around like ping-pong balls. But in real life, "there was a dull but definite bang—not much of a vibration though...just a noise," said Apollo's 13's commander, Lovell, afterward. Then the Odyssey's caution and warning lights lit up like a Christmas tree.
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On the ground, mission control was initially unperturbed. During the cryogenic tank stir, the flight controller in charge of the fuel cells and the tanks, Sy Liebergot, had his attention focused on oxygen tank one. Liebergot was an EECOM, a job title that dated back to the Mercury program days of the early 1960s. It originally meant the person was responsible for all Electrical, Environmental, and COMunications systems onboard the CSM. The communications responsibilities had recently been split out of the EECOM's job, but the name remained.

In an unfortunate coincidence, oxygen tank two's quantity sensor had failed earlier, but the two tanks were interconnected, so Liebergot was watching the quantity that tank one reported to get an idea what was in tank two.


Calm Before The Storm:: Mission control a few minutes before the explosion that would cripple Apollo 13's spacecraft. The back of flight director Gene Kranz can be seen in the foreground, while astronaut Fred Haise appears on the wall screen during a television broadcast.

As he sat in mission control at his console, with its mosaic of push buttons and black-and-white computer displays, Liebergot wasn't alone in tending to the Odyssey's electronic and life support systems. He was in voice contact with three other controllers in a staff support room across the hall. Each flight controller in mission control was connected via so-called voice loops—pre-established audio-conferencing channels—to a number of supporting specialists in back rooms who watched over one subsystem or another and who sat at similar consoles to those in mission control.

Liebergot's wingmen that day were Dick Brown, a power-systems specialist, and George Bliss and Larry Sheaks, both life support specialists. As the pressure rapidly rose in oxygen tank two and then abruptly fell within seconds, their eyes were fixed on the other cryogenic tank readouts, and they all missed the signs that tank two had just exploded.

Suddenly The Radio Link from the crew crackled to life. "Okay Houston, we've had a problem here," reported command module pilot Swigert as he surveyed the Odyssey's instruments. "Houston, we've had a problem," repeated Lovell a few seconds later, adding that the voltage of one of the two main power-distribution circuits, or buses, that powered the spacecraft's systems, was too low. But a few seconds later the voltage righted itself, so the crew began chasing down what seemed to be the big problems: the jolt of the explosion had caused their computer to reset and had knocked a number of valves closed in the attitude-control system that kept the Odyssey pointed in the right direction.

In mission control though, things weren't adding up. The spacecraft's high-gain directional antenna had stopped transmitting, and the Odyssey had automatically fallen back to its low-gain omnidirectional antennas. Liebergot and his team were seeing a lot of screwy data, dozens of measurements out of whack. Fuel cells one and three had lost pressure, and were no longer supplying current, leaving only fuel cell two to pick up the load; oxygen tank two's pressure was reading zero; the pressure in oxygen tank one was rapidly failing; and Odyssey had completely lost one of its electrical distribution buses along with all the equipment powered by it. The crew connected one of their re-entry batteries to the remaining bus in a bid to keep the command module's systems up and running.

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Liebergot's training kicked in. Simulation after simulation had taught controllers not to make rash decisions based on a few seconds of oddball data—measurements were made by imperfect sensors and had to pass through a lot of space, with a lot of opportunities to get mangled, before they turned up on a controller's screen. "Engineers that work in this business are well schooled to think first in terms of instrumentation," explains Arnold Aldrich, chief of the command and service module systems branch during Apollo 13. He was in mission control at the time of the explosion and recalls that "it wasn't immediately clear how one particular thing could have caused so many things to start looking peculiar."

So when Gene Kranz, the flight director in charge of the mission (referred to as "Flight" on the voice loops), pointedly asked Liebergot what was happening on board the Odyssey, the EECOM responded, "We may have had an instrumentation problem, Flight."

Thirty-five years later, Liebergot still ruefully remembers his initial assessment. "It was the understatement of the manned space program. I never did live that down," he chuckles.

To Kranz, the answer sounded reasonable, as he'd already had some electrical problems with the Odyssey on his shift, including one involving the high-gain antenna. "I thought we had another electrical glitch and we were going to solve the problem rapidly and get back on track. That phase lasted for 3 to 5 minutes," says Kranz. Then "we realized we'd got some problem here we didn't fully understand, and we ought to proceed pretty damn carefully."

Kranz's word was law. "The flight director probably has the simplest mission job description in all America," Kranz told Spectrum. "It's only one sentence long: 'The flight director may take any action necessary for crew safety and mission success.' " The only way for NASA to overrule a flight director during a mission was to fire him on the spot.

The rule vesting ultimate authority in the flight director during a mission was on the books thanks to Chris Kraft, who founded mission control as NASA's first flight director and who was deputy director of the Manned Spacecraft Center during Apollo 13. He had written the rule following an incident during the Mercury program when Kraft, as flight director, had been second-guessed by management. This time, as the crisis unfolded, no one had any doubts as to who was in charge. While other flight directors would take shifts during Apollo 13, as the lead flight director Kranz would bear most of the responsibility for getting the crew home.

Mission control and the astronauts tried various fuel cell and power bus configurations to restore the Odyssey to health, but anyone's remaining hope that the problem was something that could be shrugged off was dashed when Lovell radioed down: "It looks to me, looking out of the hatch, that we are venting something out into space." It was liquid oxygen spilling out from the wounded service module.

The problems were piling up at Liebergot's door. Although his voice is impressively calm throughout the recordings of the voice loops from mission control, Liebergot admits that he was almost overwhelmed when he realized "it was not an instrumentation problem but some kind of a monster systems failure that I couldn't sort out...It was probably the most stressful time in my life. There was a point where panic almost overcame me."

Liebergot gives credit to the endless emergency simulation training for getting him through the moment—as well as to the big handles that flanked each mission control console, intended to make servicing easier and jokingly dubbed "security handles" by the controllers. "I shoved the panic down and grabbed the security handles with both hands and hung on. I decided to settle down and work the problem with my backroom guys. Not to say that the thought of getting up and going home didn't pass my mind," he remembers.

The Emergency Simulations had also taught controllers "to be very careful how you made decisions, because if you jumped to the end, the sims taught you how devastating that could be. You could do wrong things and not be able to undo them," explains Kraft.



As controllers scrambled to track down the source of the venting, flight director Kranz echoed this thinking to all his controllers. "Okay, let's everybody keep cool...Let's solve the problem, but let's not make it any worse by guessing," he broadcast over the voice loops, practically spitting the word "guessing," and he reminded them that, just in case, they had an undamaged lunar module attached to the Odyssey that could be used to sustain the crew.

For now, Liebergot and his back room concentrated on ways to ease the ailing command module's power problem until they figured out what was wrong, and the crew started powering down nonessential equipment to reduce the load temporarily. The goal was to stabilize the situation pending a solution that would get the Odyssey back on track.

But Liebergot, who was starting to realize the full depth of the problem, unhappily told Kranz, "Flight, I got a feeling we've lost two fuel cells. I hate to put it that way, but I don't know why we've lost them."


Liebergot began to suspect that the venting Lovell had reported was coming from the cryogenic oxygen system, an idea bolstered when Bliss, one of Liebergot's backroom life support specialists, asked Liebergot worriedly, "are you going to isolate that surge tank?" The surge tank was the small reserve tank of oxygen that the crew would breath during re-entry, but the massive leak in the service module's cryogenic system meant that the remaining fuel cell was starting to draw on the surge tank's small supply of oxygen to keep power flowing.

Drawing On The Command module's limited reserves, such as its battery power or oxygen, was usually a reasonable thing to do in sticky situations—assuming the problem was relatively short-lived and the reserves could be replenished from the service module later. But Liebergot was now worried that the service module was running out of power and oxygen, permanently. Once he confirmed that the surge tank was being tapped, he revised his priorities, from stabilizing the Odyssey to preserving the command module's re-entry reserves. This caught Kranz momentarily off guard.

"Let's isolate the surge tank in the CM," Liebergot told Kranz. "Why that? I don't understand that, Sy," Kranz replied, noting that isolating that tank was the very opposite of what was needed to do to keep the last fuel cell running.

In effect, Liebergot's request was a vote of no confidence in the service module, and if the service module couldn't be relied on, the mission was in deep trouble. "We want to save the surge tank which we will need for entry," Liebergot prompted. The implication immediately sank in. "Okay, I'm with you. I'm with you," said Kranz resignedly, and he ordered the crew to isolate the surge tank.

For a few minutes more, Liebergot and his backroom guys fought the good fight to keep the remaining fuel cell on line, but it was looking grim. Without the fuel cell, he was going to have to power down even more command module systems in order to keep the most essential system running: the guidance system. The guidance system mainly comprised the onboard computer and a gyroscope-based inertial measurement system that kept track of which way the spacecraft was pointing. Without it, the crew wouldn't be able to navigate in space. But turning off nearly everything else in the command module was going to make it a pretty inhospitable place for the astronauts.

"You'd better think about getting into the LM," Liebergot told Kranz. It was now about 45 minutes since the explosion, and Liebergot's backroom team estimated that at the oxygen supply's current rate of decay, they would lose the last fuel cell in less than 2 hours. "That's the end right there," said Liebergot.



Kranz called Bob Heselmeyer on his loop. Heselmeyer sat two consoles over from Liebergot, and his job title was TELMU, which stood for Telemetery, Environmental, eLectrical, and extravehicular Mobility Unit. What that mouthful boils down to is that the TELMU was the equivalent of the EECOM for the lunar module, with the added responsibility of monitoring the astronaut's spacesuits. Like Liebergot, Heselmeyer had a posse of backroom guys—Bob Legler, Bill Reeves, Fred Frere and Hershel Perkins—and Kranz was about to hand them all a job. "I want you to get some guys figuring out minimum power in the LM to sustain life," Kranz ordered Heselmeyer.

It doesn't sound like a tall order—the lunar module had big, charged, batteries and full oxygen tanks all designed to last the duration of Apollo 13's lunar excursion, some 33 hours on the surface—so it should have been a simple matter of hopping into the Aquarius, flipping a few switches to turn on the power and getting the life-support system running, right?

Unfortunately, spaceships don't work like that. They have complicated, interdependent, systems that have to be turned on in just the right sequence as dictated by lengthy checklists. Miss a step and you can do irreparable damage.

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What Follows Is A Little Known story, even to many involved in the Apollo 13 mission. While they have been complimented on rapidly getting the lunar module into lifeboat mode, stretching its resources to keep the crew alive for the journey back to Earth, few realize the lunar module controllers first had to overcome a basic problem: how to get the lunar module to turn on at all. Over the last 35 years, the incredible efforts of the lunar module flight controllers have been somewhat overlooked, ironically because the Aquarius performed so well. It did everything asked of it, whether designed to or not. So the attention has focused on the titanic struggle over the crippled Odyssey. But without the lunar module controllers' dedication, foresight, and years of work, Lovell, Haise, and Swigert wouldn't have had a chance.

A fundamental problem stood in the way of getting the lunar module on line. Call it the step-zero problem. They couldn't even turn on the first piece of equipment in the lifeboat checklist because of the way the Aquarius had been designed to handle the coast between the Earth and the Moon.

Remember that for most of this coast, the lunar module and the command and service module were docked, connected by a narrow transfer tunnel, with almost everything on the lunar module turned off to save power. A number of critical systems in the lunar module were protected from freezing by thermostatically controlled heaters. During the coast, these heaters were powered via two umbilicals from the command module, which in turn got its power from the service module.

Within the Odyssey, the umbilicals were connected to a power distribution switch that shifted the lunar module between drawing power from the Odyssey and drawing power from its own batteries, the bulk of which were located in the descent stage. Here was the hitch. The distribution switch itself needed electricity to operate, which the Odyssey could no longer supply.

With the last fuel cell running out of oxygen, the astronauts needed another way to get the lunar modules batteries on line, fast.

The lunar module controllers were already on the case when Kranz's order came through. Back in the staff support room, the lunar module consoles were right beside the EECOM's support controllers' consoles, separated by a paper strip chart that recorded the activity of the lunar module heaters. From the start of the crisis, they had front-row seats as Brown, Bliss, and Sheaks tried to save the command and service module with Liebergot. It hadn't been long before Brown turned to the lunar module controllers and said, "I'll bet anything that oxygen tank blew up," remembers lunar module controller Legler. "Bill Reeves and I put a lot of stock in what Dick Brown said, and if that was true, the CSM was going to be out of power before long and we were going to have to use the LM as a lifeboat."

Looking at their strip chart, Legler and Reeves could see the lunar module heater activity had flatlined—meaning the electrical bus in the Odyssey that was connected to the umbilicals was no longer supplying power to the Aquarius. "We had lost power to the switch that was used to transfer power from the LM descent batteries. So they would have been unable to turn on the LM," says Legler.

The large batteries in the descent stage were essential to powering up most of the lunar module's systems. They were connected to the lunar module's power distribution system via relays—relays that required power to operate, power that was no longer available from the command module. Fortunately, smaller batteries in the lunar module's ascent stage could be tapped independently of the switch in the Odyssey—but they could power only some systems for a limited amount of time. In order to get systems such as life support and the computer running, the ascent batteries had to be connected to the power distribution system, energizing the relays and so allowing the descent batteries to be brought on line.

Nobody had ever planned for this situation. Legler and Reeves began working out a set of ad hoc procedures—step-by-step, switch-by-switch instructions for the astronauts—that would coax some power through the maze of circuits in the Aquarius from the ascent batteries to the relays. Working from wiring and equipment diagrams of the lunar module, it took them about 30 minutes from the time of Brown's warning about the state of the command module to finish the list of instructions. The final list involved about "10 to 15" switch throws and circuit breaker pulls for the crew, remembers Legler. Once the relays had electricity, the crew could switch over from the Odyssey's now-dead umbilicals and start powering up the lunar module's life support systems in lifeboat mode, an even more complicated process.

Fortunately, somebody had already been working on that problem for months.

A Year Earlier, in the run-up to the Apollo 10 mission, the flight controllers and astronauts had been thrown a curveball during a simulation. "The simulation guys failed those fuel cells at almost the same spot," as when Apollo 13's oxygen tank exploded in real life, remembers James ("Jim") Hannigan, the lunar module branch chief, "It was uncanny."

Legler had been present for the Apollo 10 simulation when the lunar module was suddenly in demand as a lifeboat. While some lifeboat procedures had already been worked out for earlier missions, none addressed having to use the lunar module as a lifeboat with a damaged command module attached. Although Legler called in reinforcements from among the other lunar module flight controllers, they were unable to get the spacecraft powered up in time, and the Apollo 10 simulation had finished with a dead crew.

"Many people had discussed the use of the LM as lifeboat, but we found out in this sim," that exactly how to do it couldn't be worked out in real time, Legler says. At the time, the simulation was rejected as unrealistic, and it was soon forgotten by most. NASA "didn't consider that an authentic failure case," because it involved the simultaneous failure of so many systems, explains Hannigan.


But the simulation nagged at the lunar module controllers. They had been caught unprepared and a crew had died, albeit only virtually. "You lose a crew, even in a simulation, and it's doom," says Hannigan. He tasked his deputy, Donald Puddy, to form a team to come up with a set of lifeboat procedures that would work, even with a crippled command module in the mix.

"Bob Legler was one of the key guys," on that team, recalls Hannigan. As part of his work, Legler "figured out how to reverse the power flow, so it could go from the LM back to CSM," through the umbilicals, says Hannigan. "That had never been done. Nothing had been designed to do that." Reversing the power flow was a trick that would ultimately be critical to the final stages of Apollo 13's return to Earth.

For the next few months after the Apollo 10 simulation, even as Apollo 11 made the first lunar landing and Apollo 12 returned to the moon, Puddy's team worked on the procedures, looking at many different failure scenarios and coming up with solutions. Although the results hadn't yet been formally certified and incorporated into NASA's official procedures, the lunar module controllers quickly pulled them off the shelf after the Apollo 13 explosion. The crew had a copy of the official emergency lunar module activation checklist on board, but the controllers needed to cut the 30-minute procedure to the bare minimum.

The lunar module team's head start stood them in good stead. Although Liebergot and his team had initially estimated 2 hours of life left in the last fuel cell when Kranz had asked Heselmeyer and his team to start working up how to get life support running in the lunar module, the situation was rapidly worsening. By the time the crew actually got into the Aquarius and started turning it on, the backroom controllers estimated there were just 15 minutes of life left in the last fuel cell onboard the Odyssey.



With The Lunar Module's life support systems coming on line, the immediate threat of death to the crew had been suspended, and it was time to start thinking about how to get the astronauts home.

Jerry Bostick was the chief of the flight dynamics branch, the part of mission control that looks after a spacecraft's trajectory—where it is, where it's going, where it should be, and how to get it there. The controllers of the flight dynamics branch sat in the front row of mission control, which they had proudly dubbed "the Trench." As they listened to the crew in space and the systems controllers in the row behind them struggle with the explosion's aftermath, "we went into the mode of okay, well, can we come back home immediately?" remembers Bostick. The Trench soon calculated that if the crew used the Odyssey's main engine and burned every last drop of fuel, they could turn around and come straight back to Earth, in a procedure known as a direct abort.

But the main engine was in the service module, and who knew what damage had been done to it? It might malfunction: in the worst case, firing it up could result in another explosion and kill the crew instantly. The other option was to let Apollo 13, carried forward by its momentum and the moon's gravity, go around the moon. There, gravity would pull Apollo 13 around the back side of the moon, accelerate it, and sling the spacecraft back toward Earth. This journey would take several days, however, and the lunar module was intended to support only two men for two days—not three men for four. If the crew didn't get home fast, they could run out of power and die.

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Kranz says this was his toughest call on Apollo 13. "My team was pretty much split down the middle. Many of my systems controllers wanted to get home in the fastest fashion possible. The trajectory team did not want to execute a direct abort because it had to be executed perfectly. If we didn't get the full maneuver, more than likely we would crash into the moon," he explains, "I was of the frame of mind that said, 'Hey, we don't understand what happened here...and if we execute a direct abort, we're not going to have much time to think about it...We needed to buy some time so that when we did make a move, it would be the proper move.' "

Weighing the concern that the Aquarius wouldn't cut it on a longer return journey, Kranz told Spectrum he had "a lot of confidence in my lunar module team." Apollo 13 was Kranz's fourth mission involving a lunar module. "I knew it was a very substantial spacecraft...I was pretty much betting that this control team could pull me out of the woods once we decided to go around the moon."

Kranz made his decision. The main engine was out. Apollo 13 was going around the moon.

There was, of course, a fly in the ointment. During earlier Apollo missions, the outgoing trajectory of the spacecraft had been selected so that if the service module's main engine failed for any reason, the slingshot effect would aim the command and service module perfectly at Earth, a so-called free-return trajectory. But this trajectory put very tight constraints on the mission timeline, and for Apollo 13, it had been abandoned.

"We were on a non-free-return trajectory. If we did nothing, we'd whip back towards the Earth but miss it by several thousand miles," the Trench's Bostick explains.

As the question of trajectory was being decided a shift change was going on at mission control. When the explosion occurred, Kranz and his controllers—collectively known as the White Team—had been about an hour away from the end of their shift. As was common, most of the next shift—the Black Team, led by Glynn Lunney—had already shown up, so as to be able to take over running the mission seamlessly from their predecessors, and they had been on hand throughout the crisis.

As Kranz's team gathered up to leave mission control, Bostick went to speak to the incoming flight director, Lunney. By good fortune, Kranz and Lunney were perfectly matched to the different phases of the crisis they would be faced with. Kranz was a systems guy—he knew the internals of the spacecraft better than any other flight director, the ideal person to cope with the second-by-second equipment failures and reconfigurations triggered by the explosion. Lunney had come up through the flight dynamics branch, making him ideally suited to get the spacecraft headed in the right direction.

"Kranz was there at the right time to make the decisions that had to be made rapidly, and then, when Lunney took over he brought a calmness to the control center to do the right things once they had gotten stabilized...They turned out to be a wonderful pair," says their boss at the time, Kraft.

So Bostick speaking to the perfect audience when he voiced his concerns. "We need to get this thing back to a free-return trajectory," Bostick told Lunney. Lunney instantly agreed, but this left Bostick with a problem. Getting Apollo 13 onto a free-return trajectory required a solid push from a big engine. With the Odyssey and Aquarius docked together and the main service module engine out, that left only the engine attached to the lunar module's descent stage, designed to be used only for the relatively short period of time needed to land the Aquarius on the moon. "It was a problem, because we didn't have capability in the control center to calculate the result of a docked maneuver" using the descent engine, remembers Bostick.

During a mission, controllers called on a bank of mainframe computers in a Manned Spacecraft Center facility set up and maintained by IBM, known as the Real Time Computer Complex (RTCC), to calculate the length and direction of engine burns needed to produce a given trajectory. To do these calculations, the mainframes were programmed with information about the spacecraft, such as their mass, center of gravity, how much thrust the engine produced, and so on. Unfortunately for Apollo 13, the program to calculate how the conjoined command and lunar module could be maneuvered using just the descent engine simply didn't exist.


"So the first thing we did was call our computer guys and say 'Hey, call all the IBM guys in and start writing some software!" says Bostick with a laugh. As a backup, the mission planners who originally put together the Apollo 13 mission were called in to double-check the RTCC's results. "In 2 or 3 hours we were able to come up with a free-return maneuver. I think it made everybody feel a lot better—including the astronauts." Bostick remembers talking to the crew after the mission. "When we executed the free-return burn it made them feel that they might get out of this thing alive," he says.

Kranz's Team Hadn't gone home after its shift. The White Team now formed the nucleus of a new Tiger Team, dedicated to figuring out the fastest way possible to get the crew home, given that the spacecraft was going around the moon. They also had to work out how to stretch the lunar module's consumables to last the entire trip and how to get the command module reactivated and configured to survive a re-entry—the astronauts' only way to get home alive.

Arnie Aldrich, the CSM branch chief, had joined the Tiger Team, along with another EECOM, John Aaron. An hour before, Aaron had been at home, standing in front of the mirror shaving, preparing to come in for his shift, when his wife brought him the phone, saying his boss, Aldrich, was on the line. Recalls Aaron, "He said 'John, I need to ask you some questions. There's something significant that's happened out here and these guys can't quite figure it out. It's not going well.' "

Aldrich called Aaron for a couple of reasons. One was that Aaron was an expert on the command and service module's instrumentation system. The other was that Aaron was one of the best mission controllers in NASA.

Four months earlier, Aaron had saved the Apollo 12 mission when, during launch, the rocket was struck by lightning—twice. The second strike knocked the CSM's fuel cells off line, sent the guidance system spinning, and scrambled telemetry to the ground. With warning lights blazing and alarms sounding, it looked like the crew would have to abort the mission, scant seconds after liftoff.

Aaron was in the EECOM's seat for the launch, and as he watched the scrambled data ripple across his console, he was suddenly reminded of a ground test he had seen a year earlier where an electrical malfunction had caused a similar problem. The crazy pattern of the data on his console "was a pattern that I remembered," says Aaron. And, thanks to hours of research he'd put in after the ground test, he knew how to fix it. He uttered the terse command, "Set S.C.E. to Aux," to his flight director, Jerry Griffin. Griffin, like everyone else in mission control, had no clue what that meant. Nevertheless, trusting in his EECOM, Griffin ordered the command to be passed up to the crew immediately. The corresponding switch was flipped onboard and valid telemetry was restored. With valid data, Aaron could see that the fuel cells were off line, and with a second command to reset the cells, Apollo 12 was on its way to moon. The incident cemented Aaron's reputation as a "steely-eyed missile man."

So, when Apollo 13 ran into trouble, Aaron was Aldrich's go-to guy. "I had a very good group of people working for me at the time of the explosion, but we were scratching our heads, and the very best person I had was John Aaron," says Aldrich.

After the explosion, Aldrich had moved into the spacecraft analysis, or SPAN, room, located across from mission control. The SPAN room was fitted out with more consoles and acted as a bridge between the flight controllers and the army of engineers who had actually designed and built the spacecraft. "In there were supervisors like me and executives from the engineering organizations in NASA and the manufacturers, and this group would sit together and monitor the flights," says Aldrich. The SPAN room had come into being because "we learned during Mercury that we wanted immediate access to the manufacturers, that we needed clear and unfiltered data very rapidly," says Kranz.

Over the phone, Aaron asked Aldrich to walk around behind the consoles in the SPAN room and describe what he saw. "I started asking him: tell me what this measurement says, tell me what that measurement says. And that went on for about ten minutes," says Aaron.

In the data Aldrich read to Aaron, Aaron was looking for a pattern that would map to failures in the instrumentation system onboard the Odyssey, but he was coming up empty. "I told Arnie, 'Well, I'll be right there. In the meantime tell those guys they've got a real problem on their hands,' " says Aaron.

As the lunar module controllers raced to power up the Aquarius, Aaron had made it in to mission control. "When I walked in the room, I intentionally did not put a headset on because I could see each of the flight controllers had zoomed in and were trying to sort the problem out from the perspective of their individual subsystem," he says. He walked behind the controllers, looked at their data, and listened to what they were saying to the back rooms. Finally he sat down beside the embattled command and service module controller Liebergot and plugged his headset in. "I said, "Sy, we've got to power the command module down," recalls Aaron.

[Wolfala]

Aaron didn't just want the command module powered down to minimal systems only. He meant powered down as in off. No guidance system, no heaters to keep back the cold of space, no telemetry to help controllers diagnose the problem. Nothing. Aaron was concerned that even a minimal power draw from the batteries would leave them with nothing for re-entry.



Aaron remembers debating with Gary Coen, one of the controllers with responsibility for Odyssey's guidance system. "He was pleading with me to leave the heater circuit on in the inertial platform in the CM," says Aaron. The inertial platform, which gave the computer raw data about which way the spacecraft was pointing, was never designed to handle extreme cold. "He said 'John, [the heater] only takes 0.4 amps..if we turn it off, the platform may never work again.' And I said, 'Well, Gary, just do the math. 0.4 amps times 48 hours—we gotta turn it off. If it doesn't work again, we'll just have to figure out how to get home without it.' "

But Without The Odyssey's Guidance System telling the crew precisely which way they were pointing in space, how would they be able to align the spacecraft correctly to perform the free-return trajectory maneuver?

The answer was to rely on the lunar module's guidance system, which had at its heart an identical computer to the one in the Odyssey's guidance system. However, the lunar module's guidance system had been powered off for most of the way to the moon—it had no clue as to which way it was pointing. The crew would have to transfer the alignment information manually from the command module's computer to the lunar module's computer before pulling the plug in the Odyssey.


Doing so would require some good old-fashioned arithmetic. "You could read the angles out of one computer and type them into the other, but you had to invert them," because the Odyssey and Aquarius were docked head to head, and therefore pointed in opposite directions, explains Aaron. The job fell to Lovell onboard the Aquarius, but "because I had made mistakes in the arithmetic several times during sims..I asked the ground to confirm my math," said the commander afterwards. The Trench broke out pencil and paper and confirmed the angles.

As soon as possible after the crew aligned the lunar module's guidance system for the free-return trajectory maneuver, they shut down the command module completely. In the end, the inertial platform heater circuit breaker "was the last circuit breaker we pulled," says Aaron.

Now Aaron And The Other Members Of The Tiger Team were gathered in a room near mission control. Kranz soon arrived and looked around the crowded space. The controllers were subdued and shaken—they had failed to contain the crisis, and the crew was still in extreme danger. But the last thing the astronauts needed was for controllers to begin second-guessing themselves.

Confidence was part of the bedrock upon which mission control was built. When prospective controllers joined NASA, often fresh out of college, they started out by being sent to contractors to collect blueprints and documents, which they then digested into information that mission controllers could use during a mission, such as the wiring diagrams the lunar module controllers had used to figure out how to power up the Aquarius. After that, the proto-flight controllers started participating in simulations. The principal problem NASA had with these neophytes was "one of self-confidence," explains Kranz. "We really worked to develop the confidence of the controllers so they could stand up and make these real-time decisions. Some people, no matter how hard we worked, never developed the confidence necessary for the job." Those not suited for mission control were generally washed out within a year.

Now Kranz feared his controllers, battered by the events of the last hour, would lose their nerve. What happened next was a spectacular moment of leadership. "It was a question of convincing the people that we were smart enough, sharp enough, fast enough, that as a team we could take an impossible situation and recover from it," says Kranz. He went to the front of the room and started speaking. His message was simple. "I said this crew is coming home. You have to believe it. Your people have to believe it. And we must make it happen," recalls Kranz.

In the Ron Howard movie, this speech was "simplified into 'Failure is not an option,' " chuckles Kranz, who never actually uttered the now famous phrase during the Apollo 13 mission. Still, Kranz liked it so much, because it so perfectly reflected the attitude of mission control, that he used it as the title of his 2000 autobiography.

Kranz's speech electrified the room. "Everybody started talking and throwing ideas around," remembers Aaron.

Kranz appointed three flight controllers as his key lieutenants. Aldrich was put in charge of assembling the master checklist for powering the command module and other re-entry procedures. A lunar module controller, William Peters, was ordered to make sure the Aquarius lasted long enough to get the crew close to Earth. And Aaron was put in charge of devising how electrical and other life support systems would be used so that as the crew turned on the command module again prior to re-entry, they'd be able to get it up and running and complete the descent through the Earth's atmosphere before the batteries were exhausted.

Aaron's main problem was that, as with the Aquarius, powering up the command module was a complex procedure, made even more difficult by the fact that, unlike the lunar module, the Odyssey was never supposed to be powered down at any point during the mission. "The only power-up sequence we knew was the one that started two days before launch," Aaron remembers. But judging by what was left in the Odyssey's batteries, "we had just a couple of hours at full power," he says.



Aaron listened to the hubbub of ideas on how to get the command module going and decided it was time to step in. "I started throwing some ideas out as to how the power-up sequence could be altered," he told Spectrum. Controllers immediately started to object, explaining why it was vital that one aspect or another of the sequence remain untouched.

Aaron decided to chuck them all out of the room—with the exception of Jim Kelly, a backroom command and service module controller who specialized in the electrical power system—to give himself a chance to think. "I said 'Go get some coffee and come back here in 45 minutes, and Jim and I will have a timeline of what we can turn on and when for a rudimentary re-entry sequence."

Aaron and Kelly took some paper and started sketching out a timeline, blocking out how much power each system in the command module would use as it was brought on line. "We didn't have any computer programs to do this," says Aaron. But, thanks to the simulations, the pair had been trained in "all kinds of situations where power failures happened. Mostly we were just sketching the timeline out from memory and what we had learned from training," says Aaron.

The other controllers returned to find a big block diagram drawn on the blackboard. "They came back in, and I started describing" the timeline, remembers Aaron, "That started the brokering process, because every controller still wanted their favorite piece of equipment on and the earlier the better."

The brokering process, with Aaron acting as the final arbiter, would continue for another two or three days, refining the timeline and fleshing it out until the sequence was finally ready. Aaron's work would raise his stock among his colleagues even higher. He "just had a knack for the job...He was always thinking ahead, always capable of making the best of a tough situation and getting us out of it," remembers Kraft.

Integrating the power-up sequence with other tasks that would have to be done before entry into a set of procedures that could be read up to the crew was Aldrich's job. The result, for a time the most precious document in the U.S. space program, started out as a typewritten document, but as it was revised over and over, it was "updated in pen and pencil...It was five pages long," says Aldrich, who still has the final checklist in his possession. "I haven't looked at it in quite a long time. I know where it is, but it's buried!" protested Aldrich when pressed for more details, revealing that he has kept quite a scrapbook from his 46 years and counting in the space business.

Kranz's Tiger Team worked closely with the inhabitants of the Mission Evaluation Room (MER), who were located in the building next to mission control. While the SPAN room was designed to act as a communications conduit between mission control and the engineers who had actually built and designed the spacecraft, the MER was where the problems posed by mission control actually began to be solved.

The MER was established during the Mercury program. In the early days of the program, the same people who built the spacecraft would staff the consoles in mission control. But it turned out that "people didn't have time to be responsible for the engineering and also put all the time in learning how to operate missions...so there was a split," says Aldrich. In mission control was a "mission team, which really knew how the flight was to be executed, what the possible trouble spots might be, and was prepared to deal with things that came up, but it frequently would need more engineering help," to deal with questions that cropped up concerning one piece of equipment or the other, Aldrich explains. In the MER would be "an engineering team that was pretty well informed, but which wasn't directly engaged with the flight on a first-hand basis," says Aldrich.

[Wolfala]

The MER was big enough to house dozens of engineers and if a problem couldn't be solved by those present, they could call on engineers throughout NASA's nationwide network of RandD centers as well as the engineers of the contractors who built the spacecraft. North American Aviation, based in Downey, Calif., (now part of Boeing Co., Chicago), built Apollo's command and service modules, while Grumman Aerospace, based in Bethpage, N.Y., (now part of Northrop Grumman, Corp., Los Angeles), built the lunar module.

As procedures for powering up the Odyssey or stretching the Aquarius's life support system were developed in mission control, hundreds of engineers in California and New York would test them out in the same factories where the spacecraft were built.

"In Apollo 13 movie, you see Grumman," trying to hedge its support for some of the risky tactics being employed by mission control, and "that did not happen," remembers Kranz, who is otherwise "very pleased" with Ron Howard's movie. [To see what the other controllers thought of the movie, see sidebar,  Mission Control at the movies ."The contractor support was absolutely superb," says Kranz determinedly. "The contractors knew what was at risk for every mission. If we had a problem and we turned to them, they gave us everything we needed."

After Apollo 13 Performed the free-return trajectory maneuver using the lunar module's descent engine, the debate went on about the fastest way to get the crew home. If no changes were made to the trajectory, the crew would splash down in the Indian Ocean in about four days. But there were no recovery forces to pick up the command module if it ended up in that part of the globe.

Bostick and his flight dynamics controllers immediately began working on how to shave some time off the return journey and have the splashdown happen in the Pacific, where all the recovery forces had already been deployed. "We concluded we could do that fairly easily and speed up [the splashdown] by about 12 hours, but we had also worked up an option that would get back to the Pacific and speed it up by 36 hours," says Bostick. But the 36-hour option would have involved jettisoning the service module immediately, exposing the all-important re-entry heat shield to space for a long time, and required nearly every drop of fuel left in the Aquarius's descent stage. Neither of these actions sounded appealing.


In any case "by then the systems guys had really done a bang-up job of squeezing the consumables" in the lunar module, says Bostick. They had done this principally by turning off nearly every system in the Aquarius except for guidance, communications, and a water/glycol cooling system that was needed to stop certain systems from overheating.

"Most of the water [onboard] was used for cooling; it was our most critical resource," explains Legler, who was the lead controller responsible for managing the Aquarius's power and water usage. The two consumables were interrelated; the fewer systems that were turned on and drawing power, the less water would be needed for cooling. Normally, fully powered up, the Aquarius's systems drew 50 to 75 amperes, and by dint of hard work, "we powered it down to about 12 amps," says Legler. Twelve amps is about as much power as a vacuum cleaner uses. Unfortunately for the crew there was no power in the budget to run heaters to keep the crew warm, and temperatures inside the spacecraft began to drop sharply.

With the Aquarius now expected to go the distance, the risky 36-hour option wasn't needed, and the 12-hour maneuver was chosen.

This required another burn from the lunar module's descent engine, one that would take place 2 hours after Apollo 13's closest approach to the moon. The point of closest approach was known aspericynthion, or PC for short, and so the trajectory adjustment was called the "PC+2 burn."

The PC+2 burn needed to happen exactly right, and the Trench insisted the lunar module's computer be used to control it. But the lunar module's guidance system used a lot of power, and the Trench agreed that if they could use it for the PC+2 burn, they wouldn't ask for it again. Almost exactly 24 hours after the oxygen tank explosion, the crew completed the burn and shut down the navigation system. From here on out, the astronauts would be flying by the seat of their pants.

 As Apollo 13 sped toward Earth, mission control was beginning to worry about a new problem. While the lunar module had enough spare oxygen to accommodate Swigert as well as the intended lunar module crew of Lovell and Haise, carbon dioxide was beginning to build up. Normally lithium hydroxide (LiOH) canisters absorbed the gas from the air and prevented it from reaching dangerous levels, but the canisters onboard the Aquarius were being overwhelmed. The Odyssey had more than enough spare LiOH canisters onboard, but these canisters were square and couldn't fit into the holes intended for the lunar modules' round canisters.

Mission control needed a way to put a square peg into a round hole. Fortunately, as with the lunar module activation sequence, somebody was ahead of the game.

As reported in Lost Moon, Lovell's book about the Apollo 13 mission (cowritten by Jeffery Kluger; republished as Apollo 13), Ed Smylie, one of the engineers who developed and tested life support systems for NASA, had recognized that carbon dioxide was going to be a problem as soon as he heard the lunar module was being pressed into service after the explosion.

For two days straight since then, his team had worked on how to jury-rig the Odyssey's canisters to the Aquarius's life support system. Now, using materials known to be available onboard the spacecraft—a sock, a plastic bag, the cover of a flight manual, lots of duct tape, and so on—the crew assembled Smylie's strange contraption and taped it into place. [See photo, Breathing Easy]. Carbon dioxide levels immediately began to fall into the safe range. Mission control had served up another miracle.


(Breathing Easy:: To prevent carbon dioxide poisoning, the crew jury-rigged a filter in the lunar module. Astronaut Jack Swigert is on the left.)

 Although The PC+2 burn had been right on the money, the Trench was increasingly unhappy about the Odyssey and Aquarius's trajectory. Something was pushing the spacecraft off course (afterwards it would be determined that a water vent on the Aquarius had been acting like a little rocket jet, gently sending Apollo 13 in the wrong direction) and they needed another burn to correct the trajectory. But the Trench had given up the navigation system after the PC+2 burn. "We had to come up with some way to align the spacecraft" properly for the corrective burn, Bostick explained to Spectrum.

One of Bostick's controllers, Charles ("Chuck") Dietrich, remembered an alignment technique that had been developed for earlier NASA missions in Earth orbit. A spacecraft could be pointed in the right direction by using a portion of the surface of the Earth as a reference marker—in this case the terminator between night and day.


"All during the Mercury, Gemini and Apollo Earth-orbit programs, that was a technique we had used, but never on a return from the Moon. It was a little more dicey there." In Earth orbit, a small alignment inaccuracy prior to a re-entry would result in the spacecraft landing miles off target, but it usually wasn't life threatening. But if Apollo 13 missed the trajectory it needed to take to re-enter safely—known as the entry corridor—the results would be disastrous as the command module skipped into space or burned up in the atmosphere. "If you missed the entry corridor by a degree, that's a real bad day," says Bostick.

The crew was cold and exhausted by this point—temperatures on board had dropped almost to freezing point. The astronauts had gotten very little sleep since the explosion, and yet they pulled off the course-correction maneuver—and a second one a day later—perfectly.

It Was Now over three days since the explosion in oxygen tank two. It was time to get ready for re-entry. The first step was to recharge the batteries in the command module, which had been significantly depleted before the lunar module came on line.

[Wolfala]

Remember how, while figuring out lunar module lifeboat procedures after the Apollo 10 simulation, Legler had worked out a way to run power from the lunar module to the command module back along the electrical umbilicals that connected the spacecraft? That was about to come in handy now, because that power could be used to recharge the Odyssey's batteries.

"The biggest problem was that initially the lunar module guys didn't know how much power they were going to need" for the Aquarius to serve its role as a lifeboat, remembers Aaron. For the first 30 hours, Aaron's power-up team didn't think the lunar module guys were going to have any power to spare for the Odyssey: about twelve hours after the explosion, "we talked to them about getting some power," says Aaron. "They threw us out of the room."

But the PC+2 burn had shortened Apollo 13's return flight sufficiently that the Aquarius would be able to supply the power needed to charge the batteries. Working with North American Aviation and Grumman, through lunar module gurus Hannigan and Mel Brooks in the SPAN room, to refine the procedure, Legler and Bill Peters wrote up the needed instructions. The charging process was "only 20 to 25 percent efficient," remembers Legler, but it was enough.

But even with fully charged batteries, the Odyssey risked running out of electricity before it splashed down. Batteries are rated using a term called ampere-hours. If you start with a 40 amp-hour re-entry battery, and then turn on a piece of equipment that uses 1 amp-hour, and it takes 8 hours to finish the re-entry and splashdown, you have only 32 amp-hours left to power everything else. But if you can delay turning on that piece of equipment until 2 hours before splashdown, now you have 38 amp-hours to go around. "It's not only a matter of how large a load is, but how long that load is on for," says Aaron. Once a system had been turned on in the Odyssey, it had to stay on, so "the only variable was how few systems could we turn on and how late could we wait?" he explains.

Aaron had an inspiration. Normally in a spaceship power-up sequence, one of the first things turned on is the instrumentation system so everyone can be sure that the rest of the sequence is progressing normally. But for Apollo 13, the instrumentation would be turned on last for a final check of the Odyssey just before re-entry began.

It Was A Gutsy Move. It required the crew—in particular the command module pilot, Swigert—to perform the entire power-up procedure in the blind. If he made a mistake, by the time the instrumentation was turned on and the error was detected, it could be too late to fix. But, as a good flight controller should, Aaron was confident his sequence was the right thing to do.

"I still wake up at nights in a cold sweat and wonder about that," an older and wiser Aaron told Spectrum, "because the one thing I wasn't conscious of, and I prided myself on being conscious of everything, was the condition of the crew." Despite the cold, and the fatigue, and the stress, the crew had voiced few complaints. "You couldn't tell from listening to their voices how bad conditions had got. When they got back I realized, 'Oh my goodness, I built this incredible procedure that had to be executed perfectly, and I handed it off to a crew that hadn't had any sleep for three days,' " shudders Aaron, "I've thought about that a lot, ever since."

But Swigert and the rest of the crew powered up the Odyssey, seemingly effortlessly. "Therein lies the reason we chose test pilots" to be astronauts, says Kraft. "They were used to putting their lives on the line, used to making decisions, used to putting themselves in critical situations. You wanted people who would not panic under those circumstances. These three guys, having been test pilots, were the personification of that theory," explains Kraft.


(Accident's Aftermath:: After being jettisoned from the command module, the Apollo 13 service module shows extensive damage, with an entire panel of its outer skin blown away.)

As part of the re-entry procedure, the crew jettisoned the damaged service module, snapping pictures and beaming down video of the huge gash in the side of the module as it tumbled into the distance [see photo, Accident's Aftermath]"There's one whole side of the spacecraft missing," radioed Lovell. "It looks like it got to the [main engine] bell, too," added Haise, validating Kranz's gut decision, four days earlier, to rule out using the main engine and go around the moon.



Then it was time to abandon the Aquarius and strap into the command module. For the lunar module controllers it was a bittersweet moment. "We were proud of the Aquarius and very thankful—it had really performed, did everything we asked it to do" remembers Legler. "It's hard to describe that feeling," says Hannigan, "thank God that we made it but..."

"Farewell, Aquarius, and we thank you," radioed Lovell back in 1970 as the astronauts jettisoned the lunar module and watched it slowly drift away. Hannigan remembers hearing Lovell's unbidden requiem for the spacecraft. "He did a good job," says Hannigan.

It was about another hour before the command module, headed for the Pacific, met the first tenuous wisps of Earth's atmosphere. Soon, as the Odyssey plunged into the atmosphere, those wisps would become a tremendous fireball of ionized air. The ionization would block radio communications for several minutes. In the meantime, the heat shield would be subjected to incredible temperatures and pressures, and if it had been cracked during the explosion four days earlier, the crew would burn up without ever being heard from again. Assuming the heat shield was okay, then the parachutes would deploy, slowing the Odyssey to a gentle splashdown—if the parachutes hadn't been turned into blocks of ice and the pyrotechnic charges intended to release them still worked. In a few more minutes Lovell, Haise, and Swigert would either be home free, or dead.


But the astronaut's last words before re-entry were not for themselves. They were for mission control. "I know all of us here want to thank all of you guys down there for the very fine job you did," Swigert transmitted. "That's affirm," chimed in Lovell.

A few seconds later, the Odyssey disappeared into a sea of radio static.

By Apollo 13, NASA had a pretty good handle on radio blackouts during re-entry, and for a given trajectory, it could work out how long—almost to the second—a spacecraft would be out of touch. In the Odyssey's case, it was about 3 minutes.

The appointed time came and went, and as the seconds turned into minutes without any sign of the Odyssey, the tension dragged out like a rusty blade through mission control.

"It was the worst time of the whole mission," agrees Kranz. "The blackout was a very difficult time for every controller. You ask yourself 'did I give the crew everything I needed to and was my data right?'...It was just a difficult time."



Bostick, the trajectory specialist, was in hell. "It was probably the worst I ever felt in my life," he told Spectrum. "My feeling was 'oh my god, we have done the impossible: we got them all the way home...and now something goes wrong in entry?...It was one of the most depressing [times] of my life..." Bostick's voice wavers for a moment, the memory still emotionally charged after thirty-five years. Then his voice strengthens into triumph, "but then, when we heard from them, it was the happiest moment of my life," he declares.

An antenna-laden plane, circling in the air as part of the recovery effort, had picked up the command module's signal: the crew had survived blackout! But even after radio contact was re-established, the astronaut's lives were still in danger. The main parachutes still had to be deployed. Kranz and the controllers stood rooted to their consoles, watching the main display on the front wall of mission control. The Odyssey was going to splash down, for good or ill, within sight of the live TV camera onboard the aircraft carrier leading the recovery effort, the USS Iwo Jima.

Suddenly, the parachutes—three red and white canopies—blossomed into view on the screen.

Pandemonium broke out in mission control. "I cried," says Kranz simply. "I think many of the controllers did. The emotional release at that instant was so intense many of us were unable to control our emotions. There were an awful lot of wet eyes that day."

Kraft was one of the few not swept away by the sight of the Odyssey gently descending into the Pacific, suspending his celebration until the crew was safely onboard the Iwo Jima. On seeing the deployed parachutes, "I felt fine," he remembers, "but I felt a lot better when I saw them walking on the deck of the carrier. That's the way I always was. Too many things could happen between the parachutes and the deck." Thirty-five years later, Kraft ponders the memory of the crew walking in the open air on the Iwo Jima. "That was one of the most excellent things I've ever seen," he finally says.

When The Crew and the flight controllers were finally reunited in Houston, there was, naturally, a raucous celebration, the highlight of which was the playing of an audio tape made by splicing together various mission control voice loop recordings. The creator was merciless, lampooning almost everyone involved, and got a great deal of mileage from Liebergot's "We may have had an instrumentation problem, Flight," and Kranz's later "I don't understand that," sound bites.

[Wolfala]

Despite President Nixon's award of the Presidential Medal of Freedom to those involved in saving Apollo 13, few dwelt on its significance at the time. They were busy building on the lessons learned from Apollo 13, and nine months later, Apollo 14 would blaze into the skies above Florida as it left for the moon. Indeed for years, although many in mission control viewed it as the highlight of their careers, they detected a sense of embarrassment in NASA about the mission—they had failed to go the moon after all—a taint that wouldn't fully be dispelled until the release of Ron Howard's movie in 1995.


Over the years that followed, the controllers left NASA one by one, leaving mission control to a new crop of flight controllers. But a chain of excellence had been forged—to this day every flight director in NASA has come up through the ranks. Each one studies the trade from flight directors who have also come up through the ranks—right back to the prototype flight director, Chris Kraft, learning the values of discipline, competence, confidence, shouldering responsibility, toughness, and teamwork, that form the foundation of mission control's culture, demonstrated so abley during the Apollo 13 crisis.

Kraft still sees the culture he helped forge in evidence today at mission control. "I think that's the one place in the space program that still has it," he says bluntly. "The people who are running the control center today are just as good as we ever had, and I can't praise them too highly."



While agreeing that today's flight controllers are top-notch, some of the other Apollo 13 veterans worry their authority is being slowly undermined. "Over the years I've seen that authority deteriorate badly," sighs Bostick, pointing to the management structure displayed during the Columbia tragedy as a worrying example. There was a "team of program managers who would meet every day and do flight planning: 'here's what we're going to do today,' and they would pass that on to the flight directors, making the flight directors just executors" of other people's decisions, Bostick says.

Aaron believes the problem stems from a lack of leadership from Capitol Hill on down. Without an urgent and agreed upon goal—such as beating the Soviets to the surface of the moon—NASA started being subjected to the conflicting demands of different individuals and political camps in Congress, says Aaron, who worked at NASA Headquarters in Washington, D.C., in the 1980s. NASA's marching orders have become "diffused and muddled....That then affects NASA management, who instead of being technical gurus, have to become amateur politicians." But—in what can only be good news for an agency now planning to return to the moon after forty years absence—Aaron, who retired from NASA in 2000, is convinced that the space program's engineers are still the best in the business. At the grass roots level at least, we "still got the Right Stuff," he says.
By: Pictures Courtesy Of NASA

To Probe Further

There is a wealth of information, online and off, about the Apollo 13 mission. Some of the best material is listed below:


Apollo, by Charles Murray and Catherine Bly Cox (South Mountain Books, 2004). Out of print for many years, this book gives an excellent account of what NASA's engineers and mission control did throughout the Apollo Program.

Lost Moon (republished as Apollo 13; Houghton Mifflin Co., 2000), by Jim Lovell and Jeffrey Kluger. Cowritten by one of the Apollo 13 astronauts, the book details what happened in space as well as the efforts of mission control.

Apollo 13: The NASA Mission Reports, edited by Robert Godwin (Apogee Books, 2000). Reprinted selections from NASA's official documentation, the book features prelaunch press kits, the transcripts of the crew debriefing after the mission, and extracts from the official investigation into the crisis.

The full text of the official investigation into the Apollo 13 accident, with a host of engineering details about the Apollo spacecraft and mission control, is available online at http://history.nasa.gov/ap13rb/ap13index.htm.

Flight, by Chris Kraft (Dutton, 2001). Kraft's autobiography details the founding of mission control in the Mercury era and continues through the end of the Apollo Program.

Failure Is Not an Option, by Gene Kranz (Simon and Schuster, 2000). The White Team flight director's autobiography gives the flight director's view of the events of Apollo 13.

Apollo EECOM, by Sy Liebergot with David M. Harland (Apogee Books, 2003). Liebergot's autobiography puts the reader in the hot seat during the Apollo 13 crisis and has many anecdotes from mission control. An accompanying CD features more than 3 hours of recordings from mission control's voice loops.

Virtual Apollo and Virtual LM, by Scott P. Sullivan (Apogee Books, 2002 and 2004, respectively). Two books with detailed three-dimensional reconstructions and cutaways of the lunar module and command and service module.

[rpm]

The movie was shorter.

[icemaw]

HOLY CUT AND PASTE BATMAN!!!

[TracerX]

I love this kind of stuff.  Thanks Wolfala.  Still reading.

[Angus]

Wolfala ....

[Airscrew]

Originally posted by rpm
The movie was shorter.

 luckly I needed to waste a couple of hours.  still a good read.

[Yeager]

That was some of the best engineering ever performed on one of the most intense engineering projects in history.  The guys who were there still ride on the cusp of the very best.

[rpm]

Originally posted by Airscrew
 luckly I needed to waste a couple of hours.  still a good read.

LOL agreed. That was the pinacle of NASA in my opinion.