“We didn’t think about the outcome if we weren’t successful. It had to work; failure was not an option.”                                  Gene Krantz

1970 – Cape Canaveral, Florida: Apollo 13, NASA’s third mission to the moon, launched on Saturday, April 11. Thumbing their collected noses at superstition, NASA launched the 13th Apollo mission at 13:13 military time that warm afternoon.

Fifty-five hours into the five-day flight, Mission Commander Jim Lovell commented to Mission Control in Houston, “It has been the smoothest flight. We are bored to tears up here.” 55 minutes later, one of the two liquid oxygen tanks exploded, severely crippling the spacecraft. Lovell and his two teammates were no longer bored.

With warning lights flashing and alarms sounding, the astronauts thought they had hit a small meteor. But when they saw an oxygen plume trailing the spacecraft, they knew they had a major catastrophe. They immediately contacted Mission Control to report, “Houston, we have a problem.”

The head of Houston’s Mission Control team, Gene Krantz, was keenly aware of the problem. One of his mission controllers, staring at a blank screen, breathed, “We’ve got more than a problem.” They had a spacecraft 200,000 miles from Earth, hurtling toward the moon at 2,000 miles per hour, with badly damaged fuel, electrical, and air systems. The moon mission was aborted.

Krantz knew within minutes that it would be statistically impossible for NASA to safely return the astronauts. He didn’t share this with his team; he didn’t need to. The lives of the Apollo 13 astronauts were in their hands and to survive, they needed a series of miracles.

The spacecraft consisted of the command module, nicknamed Odyssey, where the astronauts worked; the damaged service module, which included the main engine and oxygen tanks; and the small lunar module, whose purpose was to land on the moon and then return to the command module.

The astronauts powered down the command module to save power for re-entry and moved to the lunar module, which was not damaged. This meant almost four days of very cramped quarters with little food and water in a vehicle designed to function for only 40 hours. The big question on Krantz’s mind was whether the lunar module had enough engine thrust to power the spacecraft into the proper orbit to return to Earth. If it didn’t, they could miss earth by up to 4,000 miles.  

The astronauts endured 30-degree temperatures in the lunar module’s tight quarters. The water supply and most of the food were frozen. It did not matter; it was too cold to eat or sleep.

One day from Earth, Mission Control became aware of another serious problem. The limping spacecraft had drifted off course. The current trajectory would either cause the spaceship to bounce off the Earth’s atmosphere and be lost in space or burn up on re-entry.

Jim Lovell would have to fire the engine manually for a brief period, without computer guidance, and with zero margin for error. He would need to rely on his experience to determine the length of the burn. No one breathed on Apollo 13 or in Houston as Lovell conducted the maneuver as if he had done it a hundred times.

On Friday, April 17, a few hours before re-entry, the astronauts transferred to the command module. Carefully following Mission Control’s specific directions, the cold, hungry, sleep-deprived crew had to flawlessly execute 500 manual steps to power up the command module and re-start the engine for the final plunge to Earth.

More than 40 million Americans held their breath as Apollo 13 entered the blackout period. At Mission Control in Houston, all was silent. No returning spaceship had ever taken more than three minutes to emerge from blackout.

The flight monitor announced, “That’s three minutes. Standing by for acquisition.” Mission Control attempted to contact Apollo 13. “Odyssey, this is Houston. Do you read me?” Only the crackling static of the radio. In Houston, the families of the astronauts were holding hands. Tears ran down their cheeks.

Another minute passed. The module was past the point of return. At Mission Control, team members hung their heads. They had done all they could possibly do, but the rescue had apparently failed. Once again from Mission Control: “Odyssey, Houston, do you read?” Then the radio crackled. From Apollo 13: “Hello, Houston . . . this is Odyssey. It’s good to see you again!” The room exploded with cheers, shouts of joy and hugs all around. There were tears of happiness and relief. Welcome home, Odyssey.

Refusing to accept the impossible and maintaining hope in the face of incalculable odds, Gene Krantz, the Mission Control team, and three courageous men aboard the ill-fated Apollo 13 mission turned disaster into NASA’s finest hour.