Richard Lawrence - The Mammoth Book of Space Exploration and Disaster

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, “O 2cryonumber two tank is reading zero. Did you get that?”

“O 2quantity 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.