Disaster At A Distant Moon

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Deep Space, April 13, 1970

I felt the wall of the tunnel shiver,” recalls astronaut Fred Haise about the opening moments of a disaster that nearly marooned his Apollo 13 crew in deep space forever. At 9:08 p.m., the master alarm sounded in command module Odyssey, 205,000 miles from Earth. A short circuit had just ignited one of the liquid oxygen storage tanks and the ensuing explosion ripped through the service module attached below Odyssey, puncturing the remaining tank. As the life-giving oxygen slowly bled away into space, the last of the service module’s remaining fuel cell generators began to die.

Haise, pilot of the lunar module Aquarius, was on his first mission, headed with commander Jim Lovell and Odyssey’s pilot, Jack Swigert, for NASA’s third lunar landing. The 37-year-old from Biloxi, Mississippi, scanned Odyssey’s power gauges and saw that at least one of the two oxygen tanks was gone. “My first thought was—well, we’ve blown the lunar landing,” he later wrote. The situation was far worse.

The crew and Mission Control struggled to understand the cause and extent of the problem. At first, engineers in Houston hoped they might be seeing false instrumentation readings, but they soon faced the dismaying truth: not only was 13’s lunar landing impossible, but Odyssey would soon be powerless and uninhabitable. “It took 10 or 15 minutes to realize we’d lost both oxygen tanks,” remembers Haise. “That meant we were going to lose the mother ship.” Now it was a race to stabilize the situation, keep the trio alive, and somehow get them home.

“My life did not flash before me,” wrote Haise. “You react the same way as a pilot in an airplane emergency. In the first, short fraction-of-a-second shock you don’t think about anything. Then you focus in on what you know and what you’ve been trained to do, and do it in as cold and calculating a way as you can muster.”

NASA had no checklist to deal with the loss of the command ship. In simulations, rehearsing for such a failure had been deemed unrealistic. “Why practice dying?”

“We were in no-man’s-land,” Haise remembered. Within 90 minutes of the explosion, Odyssey’s oxygen and fuel cell power were almost gone. To save its batteries for reentry, four long days away, Haise, Lovell, and Swigert had to move into the lunar module, or LM. While they worked with Houston on a plan for survival, Aquarius would be their lifeboat.

Haise and Lovell scrambled through the connecting tunnel into Aquarius, hurrying to activate its systems before Odyssey lost all power. Especially vital was getting good gimbal angles (the correct alignment with the stars) into the LM’s guidance platform, fixing their orientation in space. If they lost Odyssey’s information before the LM’s platform was aligned, they would have little chance of steering their way home.

Powering up the LM usually took two hours—but now every minute was critical. Haise recalls that he “used the normal activation checklist, but I could see that certain items, like the rendezvous radar, the ship-to-ship VHF radio, weren’t needed. The ground and I crossed off those things in real time.” In parallel, Lovell hurriedly scribbled the guidance numbers onto a worksheet, doing the necessary math with a pencil. Worriedly, he radioed Houston to double-check his arithmetic. At last, he and Haise punched the figures into the LM computer. They had fired up the LM in one hour and 20 minutes—a record they were never able to match in subsequent simulations.

Only once in the desperate scramble to power up Aquarius did Houston and the crew get out of synch: Swigert was told to switch off the dying Odyssey’s thrusters before the LM’s attitude jets were ready to take over. For several minutes, Apollo 13 drifted aimlessly, but not long enough to tumble their guidance platform. With Aquarius’s thrusters online at last, Lovell and Haise soon had precarious control of their crippled ship.

Apollo 13 was still headed Moonward, on an orbital path that would swing around its far side and sling them back toward Earth. If they did nothing, that trajectory would miss the home planet by 45,000 miles; the ship would become their eternal, deep-space tomb. To steer a course back to splashdown, the men would have to perform a do-or-die rocket burn.

Nearly six hours after the explosion, with guidance inputs radioed from Houston, Lovell and Haise ignited the LM’s descent engine. Designed to lower them safely to the Moon, it now gave them a chance to make their way safely back to Earth. Rumbling for 30 seconds at 40 percent throttle, it delivered a near-perfect burn that at least assured them their spacecraft would hit Earth’s atmosphere in four days.

The immediate crisis past, now the game was long-term survival. Did Aquarius have enough power, cooling, and oxygen to keep the crew alive that long? “We knew it was life or death,” Haise remembered. “But we knew there was a big army back on Earth, giving 110 percent to get us back.”

Fred Haise, a fighter pilot and military test pilot who had practically lived at the Grumman plant in Long Island during the LM’s development, worked through the numbers. Aquarius had oxygen to spare. With all unnecessary systems powered down, the LM batteries would last at least four days. Water, however, was critical—not to drink, but to cool the LM’s electronics. Haise calculated that their 338 pounds of cooling water would get them back to Earth, but with just three hours to spare. For the first time, the crew and Houston dared to believe they might—barely—make it home.