Apollo 13’s problem – 11–17 April 1970 1 страница

Apollo 13’s mission was to make the third landing on the moon.

Sy Liebergot was the flight controller in charge of EECOM (Electrical & Environmental Command console) which monitored the power and life support systems. He had worked on the missions of Apollo 11 & 12.

Jim Lovell, Ken Mattingly and Fred Haise were the designated crew of Apollo 13, which would be out of communication for 40 minutes of every lunar orbit. A lunar orbit took 2 hours.

Liebergot had failed to react to loss of cabin pressure during a simulation exercise. Gene Kranz was the flight director of Liebergot’s team (Kraft had become part of the management team) and made his controllers do a simulated rescue plan which involved using the LEM as a lifeboat while still attached to the command module.

The back‑up crew of Apollo 13 were John Young, Jack Swigert and Charlie Duke. Duke caught German measles from his children. Lovell and Haise were immune because they had already had it, but Mattingly had not had it so he was replaced by Swigert.

In his biographical account Jim Lovell referred to himself in the third person, as Lovell. He described the Apollo command module:

The Apollo command module was an eleven‑foot‑tall cone shaped structure, nearly thirteen feet wide at the base. The walls of the crew compartment were made of a thin sandwich of aluminium sheet and an insulating honeycomb filler. Surrounding that was an outer shell of a layer of steel, more honeycomb, and another layer of steel. These double bulkheads – no more than a few inches thick – were all that separated the astronauts inside the cockpit from the near‑absolute vacuum of an outside environment where temperatures ranged from a gristle‑frying 280 degrees Fahrenheit in sunlight to a paralyzing minus 80 degrees in shadow. Inside the ship, it was a balmy 72.

The astronauts’ couches lay three abreast, and were actually not couches at all. Since the crew would spend the entire flight in a state of weightless float, they had no padding beneath them to support their bodies comfortably; instead, each so‑called couch was made of nothing more than a metal frame and a cloth sling – easy to build and most important, light. Each couch was mounted on collapsible aluminum struts, designed to absorb shock during splashdown if the capsule parachuted into the sea – or in the case of a mistargeted touchdown, onto land – without too much of a jolt. At the foot of the three cots was a storage area that served as a sort of second room (Unheard of! Unimaginable in the Gemini and Mercury eras!) called the lower equipment bay. It was here that supplies and hardware were stored and the navigation station was located.

Directly in front of the astronauts was a big, battleship‑gray 180 degree instrument panel. The five hundred or so controls were designed to be operated by hands made fat and clumsy by pressurized gloves, and consisted principally of toggle switches, thumb wheels, push buttons, and rotary switches with click stops. Critical switches, such as engine firing and module‑jettisoning controls, were protected by locks or guards, so that they could not be thrown accidentally by an errant knee or elbow. The instrument panel readouts were made up primarily of meters, lights, and tiny rectangular windows containing either “gray flags” or “barber poles.” A gray flag was a patch of gray metal that filled the window when a switch was in its ordinary position. A striped flag like a barber pole would take its place when, for whatever reason, that setting had to be changed.

At the astronauts’ backs, behind the heat shield that protected the bottom of the conical command module during re‑entry, was the twenty‑five‑foot, cylindrical service module. Protruding from the back of the service module was the exhaust bell for the ship’s engine. The service module was inaccessible to the astronauts, in much the same way the trailer of a truck is inaccessible to the driver in the cab. (Since the windows of the command module faced forward, the service module was invisible to the astronauts as well). The interior of the service module cylinder was divided into six separate bays, which contained the entrails of the ship – the fuel cells, hydrogen power relay stations, life‑support equipment, engine fuel and the guts of the engine itself. It also contained – side by side, on a shelf in bay number four – two oxygen tanks.

At the other end of the command module‑service module stack, connected to the top of the command module by an airtight tunnel, was the LEM. The four‑legged twenty‑three‑foot tall craft had an altogether awkward shape that made it look like nothing so much as a gigantic spider. Indeed, during Apollo 9, the lunar module’s maiden flight, the ship was nicknamed “Spider,” and the command module was called by an equally descriptive “Gumdrop.” For Apollo 13, Lovell had opted for names with a little more dignity, selecting “Odyssey” for his command module and “Aquarius” for his LEM. The press had erroneously reported that Aquarius was chosen as a tribute to Hair – a musical Lovell had not seen and had no intention of seeing. The truth was, he took the name from the Aquarius of Egyptian mythology, the water carrier who brought fertility and knowledge to the Nile valley. Odyssey he chose because he just plain liked the ring of the word, and because the dictionary defined it as “a long voyage marked by many changes of fortune” – though he preferred to leave off the last part. While the crew compartment of Odyssey was a comparatively spacious affair, the lunar module’s crew compartment was an oppressively cramped, seven‑foot eight‑inch sideways cylinder that featured not the five portholes and panoramic dashboard of the command module but just two triangular windows and a pair of tiny instrument panels. The LEM was designed to support two men, and only two men, for up to two days. And only two days.

Since the Apollo 8 broadcasts all Apollo crews had carried TV cameras, live broadcasts being actually incorporated in their flight plans. By Apollo 13 interest had dwindled and none of the US networks intended to transmit the first broadcast which was made from the LEM. Three days out Mission Control at Houston asked for a “cryostir”, a routine operation which kept the oxygen tanks in good condition. Lovell:

“OK,” Lovell said. “Stand by.”

As Lovell prepared for the thruster adjustments and Haise fnished closing down the LEM and drifted through the tunnel back toward Odyssey, Swigert threw the switch to stir all four cryogenic tanks. Back on the ground, Liebergot and his backroom monitored their screens, waiting for the stabilisation in hydrogen pressure that would follow the stir.

Of all the possible disaster scenarios that astronauts and controllers consider in planning a mission, few are more ghastly – or more capricious, or more sudden, or more total, or more feared – than a surprise hit by a rogue meteor. At speeds encountered in Earth orbit, a cosmic sand grain no more than a tenth of an inch across would strike a spacecraft with an energetic wallop equivalent to a bowling ball travelling at 60 miles per hour. The punch that was landed would be an invisible one, but it could be enough to rip a yawning hole in the spacecraft’s skin, releasing in a single sigh the tiny pressure pocket needed to sustain life.

Outside Earth orbit, where speeds could be faster, the danger was even greater. When Apollo astronauts first began travelling to the moon, one thing they dreaded most but spoke of least was the sudden jolt, the sudden tremor, the sudden boot in the bulkhead that indicated their highest of high‑tech projectiles and some meandering low‑tech projectile had, in a statistically absurd convergence, found each other like the pairs of fused bullets that once littered the battlefields of Gettysburg and Antietam, and had, like the bullets, done each other some serious damage.

In the sixteen seconds following the beginning of the cryostir, the astronauts of Apollo 13 were executing their next maneuvers and awaiting additional commands when a bang‑whump‑shudder shook the ship. Swigert, strapped in his seat, felt the spacecraft quake beneath him; Lovell, moving about the command module, felt a thunderclap rumble through him; Haise, still in the tunnel, actually saw its walls shift around him. It was nothing that Haise and Swigert had ever experienced before, nor was it anything that Lovell, with his three prior flights and weeks spent in the cosmic deep, had come across either.

Lovell’s first impulse was to be pissed off. Haise! This had to be Haise and his bloody repress valve! Once, maybe, the joke was funny. But twice? Three times? Even allowing for a rookie’s misplaced exuberance, this was pushing things too far. The commander turned toward the tunnel, to find the eyes of his crewman and hold them with an angry glare. But when the two men’s glances locked, it was Lovell who was brought up short. Haise’s eyes were huge, unexpectedly huge, saucer‑wide and white on all sides. These weren’t the crinkly, merry eyes of someone who had just gotten off another good one at the expense of the boss and was awaiting a smiley rebuke. Rather, they were the eyes of someone who was frightened – truly, wholly, profoundly frightened.

“It wasn’t me,” Haise croaked out in answer to the commander’s unasked question.

Lovell turned to his left to look at Swigert, but he got nothing. He saw the same confusion here, the same answer here, the same eyes here. Over Swigert’s head, high up in the center section of the command module’s console, an amber warning light flashed on. Simultaneously, an alarm sounded in Haise’s headphone and another warning light, on the right‑hand side of the instrument panel where the electrical systems were monitored, began to glow too. Swigert checked the panels and saw that there appeared to be an abrupt and inexplicable loss of power in what the crew called main bus B – one of two main power distribution panels that together provided juice to all of the hardware in the command module. If one bus lost power, it meant that half the systems in the spacecraft could suddenly go dead.

“Hey,” Swigert shouted down to Houston, “we’ve got a problem here.”

“This is Houston, say again please,” Lousma responded.

“Houston, we’ve had a problem,” Lovell repeated for Swigert. “We’ve had a main B bus undervolt.”

“Roger. Main B undervolt. OK, stand by, 13, we’re looking at it.”

Houston’s readings and Apollo 13’s differed: Houston’s looked bad; Apollo 13’s looked all right. Then both sets of readings began to look really bad. Lovell:

Up in the ship, however, the rosy readings that drove these hopes now began to change. Haise, who hadn’t stopped scanning his instruments since the trouble started, caught a glimpse of his bus readouts, and his temporarily high spirits fell. According to Odyssey’s sensors, main bus B, which had appeared to have rallied, had crashed again. Worse, bus A’s readings had begun to fail too. The sick bus, it seemed, was dragging the healthy one down with it. At the same time, Lovell looked over his oxygen tank and fuel cell readings and got even worse news: oxygen tank two, which a moment before had read full to bursting, was reading dry as a bone. Most disturbing, the fuel cell readouts on Odyssey’s instrument panel were the same as they were on Liebergot’s screens, with two of the three cells putting out no juice at all.

At the sight of this last reading, Lovell could have spit. If the fuel cell data were accurate, he could kiss his trip to Fra Mauro goodbye. NASA had a lot of unbreakable rules when it came to lunar landings, and one of the most unbreakable ones was: If you don’t have three in‑the‑pink fuel you don’t go anywhere. Technically, one cell would probably be enough to do the job safely, but when it came to something as fundamental as power, the Agency liked to have a fluffy cushion, and for NASA even two cells weren’t cushion enough. Lovell caught Swigert’s and Haise’s attention and pointed to the fuel cell readings.

“If these are real,” Lovell said, “the landing’s off.”

Swigert started radioing the bad news down to ground. “We’ve got a main bus A undervolt showing,” he said to Houston. “It’s about twenty‑five and a half. Main bus B is reading zip right now.”

“Roger,” Lousma said.

“Fuel cell one and three are both showing gray flags,” Lovell said, “but both are showing zip on the flows.”

“We copy,” replied Lousma.

“And Jack,” Lovell added, “O₂ cryonumber two tank is reading zero. Did you get that?”

“O₂ quantity is zero,” Lousma repeated.

Bad as these developments were, Lovell had yet another problem to contend with. More than ten minutes after the initial bang, his spacecraft was still swaying and wobbling. Each time the command service module and the attached LEM moved, the thrusters would fire automatically to counteract the motion and try to stabilize the ships. But each time they appeared to have succeeded, the ships would start lurching again and the thrusters would resume their firing.

Lovell now took hold of the manual attitude controller built into the console, to the right of his seat. If the automatic systems couldn’t bring the ships to heel, perhaps a pilot could. Lovell was concerned about keeping the spacecraft under control for more than aesthetic reasons. Apollo ships on the way to the moon did not simply fly straight and true, with the command module’s nose pointed properly forward and the LEM attached to it like a big, ungainly hood ornament. Rather, the ships rotated slowly like a 1 rpm top. This was known as the passive thermal control, or PTC, position and was intended to keep the ships evenly barbecued, preventing one side from cooking in the glare of the unfiltered sun and the other side from freezing over in the deep freeze of shadowed space. The thruster convulsions of Apollo 13 had shot the graceful PTC choreography all to hell, and unless Lovell could regain control he faced the real danger of ultra‑high and ultra‑low temperatures seeping through the ship’s skin and damaging sensitive equipment. But no matter how Lovell worked his manual thrusters, he could not seem to settle his spacecraft down. No sooner had he stabilized Odyssey than it would go off line again.

For a pilot who had been taken to space three times before, with little more than nuisance problems from his equipment, this was getting to be intolerable. The electrical system in Lovell’s smoothly functioning craft had gone on the fritz, the safe harbor of home was shrinking in his mirror at better than 2,000 miles every hour, and now he faced even greater danger because something – who knew what – kept shoving his ship this way and that.

The commander let go of the attitude controller, punched open his seat restraint buckle, and floated up to the left‑hand window to see if he could determine what was going on out there. It was the oldest pilot’s instinct in the world. Even when he was nearly 200,000 miles from home, in a sealed spacecraft surrounded by the killing vacuum of space, what Lovell really needed was a simple walk‑around, a chance to make one slow 360 degree circuit of his ship, to eyeball the exterior, kick the tires, look for damage, sniff for leaks, and then tell the folks on the ground if anything was really wrong and just what had to be done to fix it.

However, he had to settle for a look out the side window, in the hope that whatever problem Odyssey might have would somehow make itself clear. The odds of diagnosing the ship’s illness this way were long, but as it turned out, they paid off instantly. As soon as Lovell pressed his nose to the glass, his eye caught a thin, white, gassy cloud surrounding his craft, crystallizing on contact with space, and forming an irridescent halo that extended tenuously for miles in all directions. Lovell drew a breath and began to suspect he might be in deep, deep trouble.

If there’s one thing a spacecraft commander doesn’t want to see when he looks out his window, it’s something venting from his ship. In the same way that airline pilots fear smoke on a wing, space pilots fear venting. Venting can never be dismissed as instrumentation, venting can never be brushed off as ratty data. Venting means that something has breached the integrity of your craft and is slowly, perhaps fatally, bleeding its essence out into space.

Lovell gazed at the growing gas cloud. If the fuel cells hadn’t killed his lunar touchdown, this certainly did. In a way, he felt strangely philosophical – risks of the trade, rules of the game, and all that. He knew that his landing on the moon was never a sure thing until the footpads of the LEM had settled into the lunar dust, and now it looked as if they never would. At some point, Lovell understood, he’d mourn this fact, but that time was not now. Now he had to tell Houston – where they were still checking their instrumentation and analyzing their readouts – that the answer did not lie in the data but in a glowing cloud surrounding the ailing ship.

“It looks to me,” Lovell told the ground uninflectedly, “that we are venting something.” Then, for impact, and perhaps to persuade himself, he repeated: “We are venting something into space.”

“Roger,” Lousma responded in the mandatory matter of factness of the Capcom, “we copy your venting,”

“It’s a gas of some sort,” Lovell said.

“Can you tell us anything about it? Where is it coming from?”

“It’s coming out of window one right now, Jack,” Lovell answered, offering only as much detail as his limited vantage point provided.

The understated report from the spacecraft tore though the control room like a bullet.

“Crew thinks they’re venting something,” Lousma said to the loop at large.

“I heard that,” Kranz said.

“Copy that, Flight?” Lousma asked, just to be sure.

“Rog,” Kranz assured him. “OK everybody, let’s think of the kind of things we’d be venting. GNC, you got anything that looks abnormal on your system?”

“Negative, Flight.”

“How about you, EECOM? You see anything with the instrumentation you’ve got that could be venting?”

“That’s affirmed, Flight,” Liebergot said, thinking, of course, of oxygen tank two. If a tank of gas is suddenly reading empty and a cloud of gas is surrounding the spacecraft, it’s a good bet the two are connected, especially if the whole mess had been preceded by a suspicious, ship‑shaking bang, “Let me look at the system as far as venting is concerned,” Liebergot said to Flight.

“OK, let’s start scanning,” Kranz agreed. “I assume you’ve called in your backup EECOM to see if we can get some more brain power on this thing.”

“We got one here.”

The change on the loop and in the room was palpable. No one said anything out loud, no one declared anything officially, but the controllers began to recognize that Apollo 13, which had been launched in triumph just over two days earlier, might have just metamorphosed from a brilliant mission of exploration to one of simple survival. As this realization broke across the room, Kranz came on the loop. “OK,” he began. “Let’s everybody keep cool. Let’s make sure we don’t do anything that’s going to blow our electrical power or cause us to lose fuel cell number two. Let’s solve the problem, but let’s not make it any worse by guessing.”

Lovell, Swigert, and Haise could not hear Kranz’s speech, but at the moment they didn’t need to be told to keep cool. The moon landing was definitely off, but beyond that, they were probably in no imminent danger. As Kranz had pointed out, fuel cell two was fine. As the crew and controllers knew, oxygen tank one was healthy as well. Not for nothing did NASA design its ships with backup system after backup system. A spacecraft with one cell and one tank of air might not be fit to take you to Fra Mauro, but it was surely fit to take you back to Earth.

Lovell checked the readings for his remaining oxygen tank. Lovell:

The commander glanced at the meter and froze: the quantity needle for tank one was well below full and visibly falling, As Lovell watched, almost entranced, he could see it easing downward in an eerie, slow‑motion slide. Lovell was put in mind of a needle on a car’s gas gauge. Funny how you can never actually see the thing budge; funny how it always seems frozen in place, but nevertheless makes its way down to empty. This needle, though, was decidedly on the move.

This discovery, horrifying as it was, explained a lot. Whatever it was that had happened to tank two, that event was over. The tank had gone off line or blown its top or cracked a seam or something, but beyond the very fact of its absence, it had ceased to be a factor in the functioning of the ship. Tank one, however, was still in a slow leak. Its contents were obviously streaming into space, and the force of the leak was no doubt what was responsible for the out‑of‑control motion of the ship. It was nice to know that when the needle finally reached zero, Odyssey’s oscillations would at last disappear. The downside, of course, was that so would its ability to sustain the life of the crew.

Lovell knew Houston would have to be alerted. The change in pressure was subtle enough that perhaps the controllers hadn’t noticed it yet. The best way – the pilot’s instinctive way – was to play it down, keep it casual. Hey you guys, notice anything about that other tank? Lovell nudged Swigert, pointed to the tank one meter, then pointed to his microphone. Swigert nodded.

“Jack,” the command module pilot asked quietly, “are you copying O₂ tank one cryo pressure?”

There was a pause. Maybe Lousma looked at Liebergot’s monitor, maybe Liebergot told him off the loop. Maybe he even knew already. “That’s affirmative,” the Capcom said.

As near as Lovell could tell, it would be a while before the ship’s endgame would play out. He had no way of calculating the leak rate in the tank, but if the moving needle was any indication, he had a couple of hours at least before the 320 pounds of oxygen were gone. When the tank gasped its last, the only air and electricity left on board would come from a trio of compact batteries and a single, small oxygen tank. These were intended to be used at the very end of the flight, when the command module would be separated from the service module and would still need a few bursts of power and a few puffs of air to see it through reentry. The little tank and the batteries could run for just a couple of hours. Combining this with what was left in the hissing oxygen tank, Odyssey alone could keep the crew alive until sometime between midnight and 3 a.m. Houston time. It was now a little after 10 p.m.

But Odyssey wasn’t alone. Attached to its nose was the hale and hearty, fat and fueled Aquarius, an Aquarius with no leaks, no gas clouds. An Aquarius that could hold and sustain two men comfortably, and in a pinch, three men with some jostling. No matter what happened to Odyssey, Aquarius could protect the crew. For a little while, anyway. From this point in space, Lovell knew, a return to Earth would take about one hundred hours. The LEM had enough air and power only for the forty‑five or so hours it would have taken to descend to the surface of the moon, stay there for a day and a half, and fly back up for a rendezvous with Odyssey. And that air and power would last forty‑five hours only if there were two men aboard; put another passenger inside and you cut that time down considerably. Water on the lander was similarly limited.

But Lovell realized that for the moment Aquarius might offer the only option. He looked across the cabin at Fred Haise, his lunar module pilot. Of the three of them, it was Haise who knew the LEM best, who had trained in it the longest, who would be able to coax the most out of its limited resources.

“If we’re going to get home,” Lovell said to his crewman, “we’re going to have to use Aquarius.”

Back on the ground, Liebergot had discovered the falling pressure in tank one at about the same time Lovell did. Unlike the commander of the mission, the EECOM, sitting at the safe remove of a control room in Houston, was not yet prepared to give up on his spacecraft, but he did not hold out great hopes for it either. Liebergot turned to his right, where Bob Heselmeyer, the environmental control officer for the LEM, sat. At this moment, the EECOM and his lunar module counterpart could not have been in more different worlds. They were both working the same mission, both struggling with the same crisis, yet Liebergot was looking out from the abyss of a console full of blinking lights and sickly data, while Heselmeyer was monitoring a slumbering Aquarius beaming home not a single worrisome reading.

Liebergot glanced almost enviously at Heselmeyer’s perfect little screen with all its perfect little numbers and then looked grimly back at his own console. On either side of the monitor were handles that maintenance technicians used to pull the screen out for repairs and adjustments. Liebergot all at once discovered that for several minutes he had been clutching the handles in a near death grip. He released the handles and shook his arms to restore their circulation but not before noticing that the backs of both his hands had turned a cold, bloodless white.

Mission Control told the crew to shut down the fuel cells to prevent the loss of their oxygen. Lovell:

“Did I hear you right?” Haise, the electrical specialist asked Lousma. “You want me to shut the reac valve on fuel cell three?”

“That’s affirmative,” Lousma answered.

“You want me to go through the whole smash for fuel cell shut‑down?”

“That’s affirmative.”

Haise turned to Lovell and nodded sadly. “It’s official,” said the astronaut who until just an hour ago was to have the sixth man on the moon.

“It’s over,” said Lovell, who was to have been the fifth.

“I’m sorry,” said Swigert, who would have overseen the mother ship in lunar orbit while his colleagues walked. “We did everything we could.”

At the EECOM console and in the backroom, Liebergot, Bliss, Sheaks and Brown watched their monitors as the valve in fuel cell three was slammed shut. The numbers for oxygen tank one confirmed their worst fears: the O₂ leak continued. Liebergot asked Kranz to order that fuel cell one be shut next. Kranz complied – and the oxygen leak continued.

Liebergot looked away from his screen: the end, he knew, was at last here. Had the explosion or meteor collision or whatever else crippled the ship occurred seven hours earlier or one hour later, it would have been another EECOM on console at the time, another EECOM who would have attended this death watch. But the accident happened 55 hours, 54 minutes, and 53 seconds into the mission, during the last hour of a shift that by sheer scheduling happenstance belonged to Seymour Liebergot. Now Liebergot, through no fault of his own, was about to become the first flight controller in the history of the manned space program to lose the ship that had been placed in his charge, a calamity any controller worked his whole career to avoid. The EECOM turned to his right, toward where Bob Heselmeyer, the LEM’s environmental officer, sat. As Liebergot glanced again at Heselmeyer’s screen, he could not help thinking of that simulation, that terrible simulation which had nearly cost him his job a few weeks earlier.

“Remember,” said Liebergot, “when we were working on those lifeboat procedures?”

Heselmeyer gave him a blank look.

“The LEM lifeboat procedures we worked on in that sim?” Liebergot repeated.

Heselmeyer still stared blankly.

“I think,” said Liebergot, “it’s time we dusted them off.”

The EECOM steeled himself, signed back on the loop, and called to his flight director.

“Flight, EECOM.”

“Go ahead, EECOM.”

“The pressure in O₂ tank one is all the way down to 297,” Liebergot said. “We’d better think about getting into the LEM.”

“Roger, EECOM,” Kranz said. “TELMU and CONTROL, from Flight,” he called to the LEM’s environmental and guidance officers.

“Go, Flight.”

“I want you to get some guys figuring out minimum power needed in the LEM to sustain life.”

“Roger.”

“And I want LEM manning around the clock.”

“Roger that too.”

At the same time this conversation was taking place, Jack Swigert, on the center couch in Odyssey, looked at his instrument panel and discovered that while the oxygen readings might have been grim on the ground, they were downright dire in the spacecraft. Squinting through the growing darkness of his powered‑down ship, where the temperature had fallen to a chilly 58 degrees, Swigert saw that his tank one pressure was down to a bare 205 pounds per square inch.

“Houston,” he said, signing back on the air, “it looks like tank one O₂ pressure is just a hair over 200. Does it look to you like it’s still going down?”