Apollo 13’s problem – 11–17 April 1970 3 страница

If the data were right, something had arced or shorted in the lunar module’s battery, just as it had arced or shorted in the service module’s tank on Monday night. And if there had been a short, the battery, like the tank would soon go off line killing fully one quarter of a power supply that Houston and Grumman were rationing down to the last fraction of an amp. The numbers on the screen were too preliminary to be conclusive – too preliminary even for Heselmeyer to pass them on to Griffin. And if Heselmeyer didn’t pass them on to Griffin, Griffin couldn’t pass them on to Brand, and Brand couldn’t pass them on to Haise.

At the moment, that was probably just as well. Standing at his window and looking out at the growing cloud of flakes surrounding the bottom of his LEM, Fred Haise had more than enough burdens of command.

It was battery two in the LEM which had four batteries, each one designed to compensate for loss of power in any of the others. The damaged battery was still working despite the small explosion.

The astronauts were still wearing their bio‑medical sensors. Lovell pulled his off because they were becoming uncomfortable and to conserve power. When the Capcom found out he just said “OK”.

Houston wanted Odyssey to be powered up because the systems were sensitive to the cold. Capcom told Lovell that the explosion was a minor one in battery two in the LEM and that a burn for realignment of the re‑entry angle was required.

Meanwhile the crew were beginning to experience health problems and had decided to drink as little as possible when the capsule began to become cluttered with bags of urine. Venting helium was eroding the re‑entry angle.

Lovell regarded both his crewmates and reflected on what he ought to do next, but before he could reach any conclusions, his thoughts were interrupted. From beneath the floor came a dull pop, then a hiss, then another thump and vibration ratted through the cabin. Lovell leapt forward toward his window. Below the cluster of thrusters to the left of his field of vision, he could see a far too familiar cloud of icy crystals floating upward. For an instant Lovell was startled, and then just as quickly he knew what the sound and the vent were.

“That,” he said, turning to his crewmates, “was the end of our helium problem.”

They re‑established the PTC roll.

At 8 pm on Thursday, 16 April the re‑entry angle was beginning to decay again. The Atomic Energy Commission was concerned about a fuel rod in the LEM which should have been left behind on the moon, in the descent stage. Although the LEM would be jettisoned in space it would eventually fall to earth, so the Atomic Energy Commission wanted to ensure that it fell into the deepest water possible.

The food supplies in Odyssey had frozen solid. They had to decide the best way to handle the separation of Odyssey and Aquarius.

When the time came to jettison the service module, they decided Jim Lovell and Fred Haise would stay in the LEM, while Jack Swigert would scramble up into the command module. Moments before separation, Lovell would fire the LEM’s thrusters for a single pulse, pushing the whole spacecraft stack forward. Swigert would then press the button that fired the service module’s pyrotechnic bolts, cutting the huge, useless portion of the ship loose. As soon as he did, Lovell would light his thrusters again, this time in the opposite direction, backing the LEM and its attached command module – with Swigert aboard – away from the drifting service module.

Easier, but no less elegant, was the procedure for jettisoning the LEM. Before a lunar module was released on a normal mission, the astronauts would close the hatch in both the lander itself and the command module, sealing off the tunnel from the cockpits of either ship. The commander would then open a vent in the tunnel, bleeding its atmosphere into space and lowering its pressure to a near vacuum. This would allow the twin vehicles to separate without an eruption of air blowing them uncontrollably apart.

During the flight of Apollo 10 last spring, the controllers had experimented with the idea of leaving the tunnel partially pressurized, so that when the clamps that held the vehicles together were released, the LEM would pop free of the mother ship, but in a slower, more controlled way than it would if the passageway between the two spacecraft was fully pressurized. This method, the controllers figured, would come in handy if a service module ever lost its thrusters. Now, a year later, a service module had done just that and the flight dynamics officers were glad they had the maneuver tucked away in the contingency flight‑plan books. Yesterday, the procedure had been explained to Jack Lousma, and the Capcom had proudly relayed it up to Lovell.

“When we jettison the LEM,” he had reported, “we’re going to do it like we did in Apollo 10 – just let the beauty go.”

Lovell had radioed back a far more sceptical “OK.”

Finally Odyssey’s guidance system would have to be realigned for reentry. Normally this angle was checked visually against the arc of the horizon. But Odyssey would arrive on the night time side when the planet was only visible as a dim mass.

But Chuck Deiterich, the Gold Team RETRO, had an idea. “Fellows,” he said to the other flight dynamics men in the staff support room, “tomorrow around lunchtime we’re going to have a problem – specifically, we’re going to be trying to check our attitude against a horizon that isn’t there.”

He turned to the blackboard and drew a large downward arc representing the edge of the Earth. “Now while the Earth will be invisible, the stars will always be there” – he tapped a few chalk dots onto the board above his horizon – “but as fast as the ship will be moving, there might not be time to determine which ones we’re looking at.” He eliminated his stars with a sweep of his eraser.

“Of course, what we’ll also have out there,” Deiterich said, “will be the moon.” He drew a neat little moon above his ragged Earth. “As the spacecraft arcs around the planet and gets closer and closer to the atmosphere, the moon will appear to set.” Deiterich drew another moon below his first one, then another and another and another, each moving closer to the chalk horizon, until the last one vanished partially behind it.

“At some point,” he said, “the moon will set behind the Earth and disappear. It will disappear at the same time whether it’s daytime below or nighttime, whether we can see the horizon or can’t see it.” The RETRO touched the corner of his eraser to the blackboard and carefully erased only the long arc that represented the horizon, leaving all his moons behind. He pointed to the one moon that was half obscured by the horizon that was no longer there.

“If we know the exact second the moon is supposed to disappear, and if our command module pilot tells us it indeed disappears, then gentlemen, our entry attitude is on the mark.”

The temperature in the LEM was so low that the astronauts’ breath fogged the windows, cold making sleep almost impossible.

Deke Slayton was chief astronaut and was deeply concerned about the crew. He had been monitoring Apollo’s power consumption and was confident there was enough power left to power up the LEM. He called the flight director on duty, Milt Windler, to ask if the LEM could be brought back on line early if enough power had been saved. This was confirmed.

Windler called Jack Knight at the TELMU console, who in turn contacted his backroom. Knight’s assistants put him on hold, conducted some quick‑and‑dirty amp projections, and came back with the good word: the crew was free to switch on their ship.

“Jack, they’re go for power‑up,” the backroom called to the TELMU.

“Flight, he can power up if he wants,” the TELMU called to Windler.

Windler relayed this to Lousma: “Capcom, tell him to turn on the lights.”

“Aquarius, Houston,” Lousma called.

“Go ahead, Houston,” Lovell answered.

“OK, skipper. We figured out a way for you to keep warm. We decided to start powering up the LEM now. Just the LEM, though, not the command module. So open your LEM prep checklist and turn to the thirty‑minute activation. You copy?”

“Uh, copy,” said Lovell. “And you’re sure we have plenty of electrical power to do this?”

Slayton cut in. “Jim, you’ve got 100 percent margins on everything from here on in.”

“That sounds encouraging.”

The commander turned to his crewmates, gestured to the instrument panel, and with the help of Haise, went into a frenzy of switch‑throwing, completing the half‑hour power‑up in just twenty‑one minutes. As soon as Aquarius’s systems came online, the crew could feel the temperature in the frigid cockpit begin to climb. And no sooner did the temperature start to climb than Lovell took a step to make sure it climbed even further. Grabbing his attitude controller, now active again, he spun his ship in a half somersault, so that the sun, which had been falling uselessly on the rump of the service module fell across the face of the LEM.

Almost at once, a yellow‑white slash of light flowed into the ship. Lovell turned his face up to it, closed his eyes, and smiled.

“Houston, the sun feels wonderful,” he said “It’s shining straight in the windows, and it’s getting a lot warmer in here already. Thank you very much.”

After the mission they came to some conclusions about the causes of the explosion and the erosion of the descent angle:

But it was only when their engineering hunches were put to the test that they were confirmed. In vacuum chambers at the Space Center in Houston, technicians switched on a heater in a sample tank precisely as Apollo 13’s heater had been switched on and found that the thermostat did in fact fuse shut; they then left the heater on just as Apollo 13’s heater had been left on and found that the Teflon on its wires indeed burned away; finally, they stirred up its cryogenics exactly as Apollo 13’s cryos had been stirred and found that a spark indeed flew from a wire, causing the sample tank to rupture at the neck and blow off the side panel of a sample service module with it.

The only other mystery that had yet to be solved was what had caused the shallowing of the trajectory on the way home, and it was left to the TELMUs to dope this one out. Aquarius, so these flight controllers concluded, had been pushing itself steadily off course, not with some undetected leak from a damaged tank or pipe, but from wisps of steam wafting from its cooling system. The tendrils of vapor that the water‑based sublimator emitted as it carried excess heat off into space had never disturbed a LEM’s trajectory, but only because the lander was typically not powered up until it was already in lunar orbit, ready to separate from the mother ship and descend to the surface. For such a short haul trip, the invisible plume of steam would not be strong enough to nudge the lander in any one direction. Over the course of a slow 240,000‑mile glide back to Earth, however, the almost unmeasurable thrust would be more than enough to alter the spacecraft’s flight path, pushing it out of its reentry corridor altogether.

On Friday, 17 July at 10.43 am it was time for separation from the damaged service module.

“Aquarius, Houston,” Joe Kerwin called from the Capcom station.

“Go, Joe,” Fred Haise answered.

“I have attitudes and angles for service module separation if you want to copy. You don’t need a pad for it, just any old blank sheet of paper will do.”

In the spacecraft, Lovell, Haise and Swigert were in their accustomed positions, all awake and all feeling reasonably alert. Lovell had decided against the Dexedrine tablets Slayton had prescribed for his crew last night, knowing that the lift from the stimulants would be only fleeting, and the subsequent letdown would leave them feeling even worse than they did now. For the time being, the commander had decided that the astronauts would get by on adrenaline alone. Haise, his cheeks still flushed by fever, needed the adrenaline rush more than his crewmates, and at the moment he appeared to be getting it.

“Go ahead Houston,” he said, tearing a piece of paper from a flight plan and producing his pen.

“OK, the procedure reads as follows: First, maneuver the LEM to the following attitude: roll, 000 degrees: pitch, 91.3 degrees; yaw, 000 degrees.” Haise scribbled quickly and did not immediately respond. “Do you want those attitudes repeated, Fred?”

“Negative, Joe.”

“The next step is for you or Jim to execute a push of 0.5 feet per second with four jets from the LEM, have Jack perform the separation, then execute a pull at the same 0.5 feet per second in the opposite direction. Got that?”

“Go that. When do you want us to do this?”

“About thirteen minutes from now. But it’s not time critical.”

Lovell cut into the line. “Can we do it anytime?”

“That’s affirmative. You can jettison whenever you’re ready.”

With clearance from the ground to proceed, Swigert shot up the tunnel into Odyssey and took his position in front of the jettison switches in the center of his instrument panel. Lovell and Haise went to their windows. Near each of their stations, the three men had already left cameras floating, in the hope of photographing the service module’s presumably blast‑damaged exterior. Swigert had already taken the precaution of wiping Odyssey’s five windows clear of condensation, to provide an unobscured view to the outside.

“Houston, Aquarius,” Lovell called. “Jack’s in the command module now.”

“Real fine, real fine,” Kerwin said. “Proceed at any time.”

“Jack!” the commander shouted up the tunnel. “You ready?”

“All set when you guys are,” the call came back.

“All right, I’ll give you a five count, and on zero I’ll hit the thrusters. When you feel the motion, let ’er go.”

Swigert shouted a “roger,” reached over with his left hand and picked up his big Hasselblad, then positioned the index finger of his right hand over the SM JETT switch. His paper “NO” flapped to the left of it. Lovell, in the LEM, took his camera in his left hand and his thruster control in his right. Haise picked up his camera as well. “Five,” Lovell called up the tunnel, “four, three, two, one, zero.”

The commander eased his control upward, activating the jets and nudging the two‑spacecraft stack into motion. In the command module, Swigert responded immediately, snapping the service module switch.

“Jettison!” he sang out.

All three crewmen heard a dull explosive pop and felt a simultaneous jolt. Lovell then pulled down on the controller, activating an opposite set of nozzles and reversing course.

“Maneuver complete,” he called.

At their separate windows, Lovell, Swigert, and Haise leaned anxiously forward, raised their cameras, and flicked their eyes about their patches of sky. Swigert had chosen the big, round hatch window in the center of the spacecraft, but pressing his nose against it now he saw… nothing. Jumping to his left, he peered out Lovell’s window and there too saw nothing at all. Scrambling across to the other side of the spacecraft, he banged into Haise’s porthole, scanned as far as the limited frame would allow him, and there, too, came up empty.

“Nothing, damnit!” he yelled down the tunnel. “Nothing!”

Lovell, at his triangular window, swiveled his head from side to side, also saw nothing, and looked over to Haise, who was searching as frantically as he was and finding just as little. Cursing under his breath, Lovell turned back to his glass and all at once saw it: gliding into the upper left‑hand corner of the pane was a mammoth silver mass, moving as silently and smoothly and hugely as a battleship.

He opened his mouth to say something, but nothing came out. The service module moved directly in front of his window, filling it completely; receding ever so slightly it began to roll, displaying one of the riveted panels that made up its curved flank. Drifting away a little more, it rolled a little more, revealing another panel. Then, after another second, Lovell saw something that made his eyes widen. Just as the mammoth silver cylinder caught an especially bright slash of sun, it rolled a few more degrees and revealed the spot where panel four was – or should have been. In its place was a wound, a raw, gaping wound running from one end of the service module to the other. Panel four, which made up about a sixth of the ship’s external skin was designed to operate like a door, swinging open to provide technicians access to its mechanical entrails, and sealing shut when it came time for launch. Now, it appeared, that the entire door was gone, ripped free and blasted away from the ship. Trailing from the gash left behind were sparkling shreds of Mylar insulation, waving tangles of torn wires, tendrils of rubber liner. Inside the wound were the ship’s vitals – its fuel cells, its hydrogen tanks, the arterial array of pipes that connected them. And on the second shelf of the compartment, where oxygen tank two was supposed to be, Lovell saw, to his astonishment, a large charred space and absolutely nothing else.

The commander grabbed Haise’s arm, shook it, and pointed. Haise followed Lovell’s finger, saw what his senior pilot saw, and his eyes, too, went wide. From behind Lovell and Haise, Swigert swam frantically down the tunnel holding his Hasselblad.

“And there’s one whole side of that spacecraft missing!” Lovell radioed to Huston.

“Is that right,” Kerwin said.

“Right by the – look out there, would you? Right by the high‑gain antenna. The whole panel is blown out, almost from the base to the engine.”

“Copy that,” said Kerwin.

“It looks like it got the engine bell too,” Haise said, shaking Lovell’s arm and pointing to the big funnel protruding from the back of the module. Lovell saw a long, brown burn mark on the conical exhaust port.

“Think it zinged the bell, huh?” Kerwin asked.

“That’s the way it looks. It’s really a mess.”

The next task was to power up Odyssey.

In the cockpit of Aquarius, Lovell looked at Swigert and motioned him to the tunnel. Unlike the reading of the power‑up checklist fourteen hours earlier, the execution of the list would be a simple matter, requiring less than half an hour’s work by the command module pilot.

As the first switch was thrown, sending a surge of power through the long, cold wires, Lovell braced for the sickening pop and sizzle indicating that the condensation soaking the instrument panel had indeed found an unprotected switch or junction and shorted the ship right back out. It was a sound he had first heard over the Sea of Japan and one he clearly hoped he would never hear again. But as the power‑up cockpit proceeded, Swigert threw his first breaker and his second, and his third, and soon, all the crewmen heard was the reassuring hum and gurgle indicating the spacecraft was coming back to life.

EECOM John Aaron knew that the rute of energy consumption was critical. Lovell:

The way Aaron had ciphered things out, the ship could afford to pull no more than 43 amps of juice if it hoped to stay alive for the full two hours of reentry. But, having won the argument in room 210 over when to turn the telemetry on, he wouldn’t know if he was actually staying within this power budget until the command module was completely powered up and the data started streaming back from the ship. If it turned out that Odyssey was consuming juice above the 43 amp level, even for a short while, there was a real chance its batteries would be exhausted before it ever hit the ocean.

When the readings came back, they showed Odyssey’s power consumption was 2 amps higher than the level which would last. They identified the instruments which were consuming the extra power as being back‑up systems which could be shut down. This brought power consumption back to the 43 amp level which would last until splash down. The LEM was now expendable but Haise was in a very bad shape.

“Man,” Lovell muttered, “you are a mess.” Moving behind Haise, the commander wrapped him in a bear hug to share his body heat. At first the gesture seemed to accomplish nothing, but gradually the trembling subsided.

“Fred, why don’t you get upstairs and help Jack out,” Lovell said. “I’ll finish up here.”

Haise nodded and prepared to jump up the tunnel. But before he did, he stopped and took a long look around Aquarius’s cockpit. Impulsively, he pushed back toward his station. Attached to the wall was a large screen of fabric netting used to prevent small items from floating behind the instrument panel. Haise grabbed hold of the netting and gave a sharp pull; it tore free with a ripping sound.

“Souvenir,” he said with a shrug, wadding the netting into a ball, stuffing it into his pocket, and vanishing up the tunnel.

Alone in the lunar module, Lovell too glanced slowly around it. The debris of four days of close‑quarters living was collected in the cluttered cockpit, and Aquarius now looked less the intrepid moonship it had been on Monday than a sort of galactic garbage scow. Lovell waded through the scraps of paper and rubbish and moved back toward his window. Before jumping ship himself, he had one more job: steering the twin vehicles to the attitude Jerry Bostick had specified, so the LEM would drop into the deep water off New Zealand.

Lovell took the attitude control for the last time and pushed it to the side. The ship yawed slightly, jostling some of the floating paper. Without the inert mass of the service module skewing the center of gravity so badly, Aquarius was far more maneuverable, much closer to the nimble ship the simulators in Houston and Florida had conditioned Lovell to expect before this mission began. With a few practiced adjustments, he moved the lander to the proper position, then called the ground.

“OK Houston, Aquarius. I’m at the LEM separation attitude.”

“I can’t think of a better idea, Jim,” Kerwin replied.

Lovell finished configuring the LEM’s switches and systems and then, like Haise, decided that a souvenir might be in order. Reaching to the top of his window, he grabbed the optical sight and gave it a twist. It unscrewed easily and Lovell pocketed it. Looking toward the stowage area at the back of the cockpit, he found the helmet he would have worn on the surface of the moon, picked it up, and tucked it under his arm. Finally, he turned to another cabinet and retrieved the plaque he and Haise would have clamped to LEM’s front leg once they had emerged from the lander and begun to explore. None of the workers in NASA’s metal shop who had manufactured the plaque had ever expected to see it again. Now, Lovell reflected, they could stop by his office or den and take a look whenever they chose.

Holding his collected booty, Lovell sprang up the tunnel into Odyssey’s lower equipment bay, stashed his souvenirs in astorage cabinet, and movedinthe directionofthe couches. Instinctively, he moved toward the left‑hand station but when he shimmied out of the equipment bay, he discovered that while Haise was buckled into his familiar right‑hand seat, Swigert had claimed Lovell’s left‑hand spot. It was customary during the descent and reentry phase of a lunar mission for a commander to relinquish his seat to his command module pilot. During a flight in which so many of the critical moments belonged to the commander and the LEM pilot, the man in the center couch was oftentimes overlooked. Reentry, however, when the LEM that had taken his shipmates to the surface of the moon was nothing but a jettisoned memory, was essentially a command module pilot’s operation, and as a gesture of respect for both his competence as a flier and the thankless job he had performed so far, he was usually allowed to bring the ship in for its landing. Now, as reentry approached, and the commander of this mission approached his familiar station, he had to switch course and move back to a less familiar one.

“Reporting aboard, skipper,” Lovell said to Swigert.

“Aye‑aye,” Swigert answered, a bit self‑consciously. Lovell donned his headset and nodded, then Swigert signed on the air.

“OK, Houston, we’re ready to proceed with hatch close‑up.”

“OK, Jack. Did Jim get all of the film out of Aquarius?”

Lovell looked at Swigert and nodded yes.

“Yes,” Swigert said. “That’s affirmative. And we remembered to get Jim out too.”

“Good deal, Jack,” Kerwin said. “Then what we want you to do is seal the hatch and vent the tunnel until you get down to about 3 pounds per square inch. If the hatch holds pressure for a minute or so, you’re OK and you can feel free to release Aquarius.”

“OK,” Swigert said. “Copy that.”

Lovell, indicating to Swigert that he should stay where he was, wriggled back out of his couch and glided toward the lower equipment bay. Swimming into the tunnel, he slammed the LEM’s hatch and sealed it with a turn of its lever. Then he backed into Odyssey, retrieved its hatch from the spot where he had tied it down on that Monday night so long ago, and fitted it into place.

If this hatch evidenced the same balkiness it had four days ago, the LEM could not be jettisoned and the reentry could not proceed as planned. Even if the hatch did seal, it would be a few minutes before the onboard pressure sensors would confirm that the seal was tight and the spacecraft wasn’t leaking air. Naturally, without this confirmation, a safe reentry would be impossible. Lovell regarded the hatch suspiciously and then threw its locking mechanism. The latches closed with a satisfying snap. Reaching for the tunnel vent switch, he bled the air out of the passageway and into space until the pressure read 2.8 pounds per square inch. Flipping the vent switch shut, he swam back to his seat.

“Sealed?” Swigert asked.

“I hope so,” Lovell said.

With this tepid reassurance, the command module pilot flipped several switches on his instrument panel and brought the oxygen system to life, feeding fresh O₂ into the cockpit. For several taut seconds he stared at his indicator.

“Oh, no,” Swigert groaned.

“What’s wrong?” Lovell and Haise asked, practically in unison.

“Flow is high. It looks like we’ve got a leak.”

On the ground, John Aaron hunched over his EECOM screen and spotted the oxygen rate at the same time Swigert did.

“Oh, no,” he groaned.

“What’s wrong?” Liebergot, Burton, and Dumis asked, practically in unison.

“Flow is high. It looks like we’ve got a leak.”

On the air‑to‑ground loop, Swigert’s voice called out, “OK Houston, we’ve got an O₂ flow high.”

“Roger, Jack,” Kerwin answered. “Let us check it.”

As Swigert kept his eyes on his instruments, Aaron hailed his backroom. He and his engineers muttered on the line about the source of the potential leak while the three other EECOMs in the second row fretted aloud among themselves.

Within minutes, Aaron believed he had the problem sorted out. The LEM operated at a slightly lower pressure than the command module. Over the past four days, with hatches opened up and Odyssey shut off, it was Aquarius which determined the pressure in both ships. When the command module was powered up and its door was closed, the pressure sensors spotted that difference and immediately tried to pump the internal atmosphere up to what they thought it should be. In a few moments, Aaron figured, the necessary air should have been added to the cockpit and the high flow rate would stop.

“Sit tight for another minute,” he said to the people around him. “I think we’ll be all right.”

Forty seconds later, the numbers in the spacecraft and on the EECOM’s screen indeed began to stabilize.

“OK,” Swigert said with audible relief, “it’s dropping now, Joe.”

“Roger,” Kerwin called. “In that case, when you are comfortably ready to release the LEM, you can go ahead and do it.”

Lovell and Swigert looked at the mission timer on their instrument panel. It was 141 hours and 26 minutes into the flight.

“Do it in four minutes?” Swigert asked.

“Seems like a nice round figure,” Lovell answered.

“Houston,” Swigert announced. “We’ll punch off at 141 plus 30.”

Outside the cockpit’s five windows, the astronauts could see nothing of Aqarius but its reflective silver roof plates, just a few feet away from the glass of their portholes. Three and a half minutes elapsed.

“Thirty seconds to LEM jettison,” Swigert said.

“Ten seconds.”

“Five.”

Swigert reached up to the instrument panel, ripped away his “NO” note, and balled it up in his palm.

“Four, three, two, one, zero.”

The command module pilot flipped the toggle switch and all three crewmen heard a dull, almost comical pop. In their windows, the silver roof of the lunar lander began to recede. As it did, its docking tunnel became visible, then its high‑gain antenna, then the array of other antennas that bristled from its top like metal weed. Slowly, the unbound Aquarius began a graceful forward somersault.