With the success of Neil Armstrong’s seat-of-the-pants first lunar landing on Apollo 11, and the pinpoint accuracy of putting the Apollo 12 lunar module right where NASA planned next to a previously-landed Surveyor spacecraft, the expectations on Apollo 13 were to expand that winning streak, and to gain new knowledge about the Moon in the Frau Mauro highlands. No one thought this would instead turn out to be one of the most harrowing chapters in our young space program.

It seems hard to imagine that forty-five years have now passed since the launch of Apollo 13. But what is even harder to understand is that with this third lunar mission, the public had already become so apathetic with the idea of exploring another world, that few people paid much attention when liftoff occurred at 1:13 pm CST on 11 April 1970.

At a recent event at the San Diego Air & Space Museum commemorating the mission, Apollo 13 commander Jim Lovell said, “Forty-five years ago, I was a lot younger and things happened a lot faster.” A good example of this was the launch of the Saturn V rocket. Even though this was Lovell’s fourth spaceflight, and second ride on a Saturn V, the whole idea of being in space took a while to adjust. “It’s an exhilarating feeling,” Lovell explained, “once your stomach gets used to it. It takes about six hours for your stomach to slow down. After that, there’s no weight, it’s easy to move around, there’s no up or down.”

Apollo 13 astronauts and Nixon
Apollo 13 astronauts with President Richard M. Nixon (from left) Fred Haise, Jim Lovell and John Swigert during the post-mission ceremonies at Hickam Air Force Base, Hawaii. Credit: NASA

At that point the crew of Lovell, Lunar Module pilot Fred Haise, and Command Module pilot Jack Swigert, were to get down to business preparing for their upcoming landing. The third stage of the Saturn V, the S-IVB, had already given them the boost needed to escape Earth’s gravity and shoot off toward the Moon at nearly 25,000 miles an hour. Confidence ran so high after previous lunar missions had gone like clockwork that Apollo 13 was the first to be sent to the Moon without having a free return trajectory. What that meant was that if something went wrong on the injection burn into lunar orbit, they would not automatically swing around the backside and get flung back toward a safe splashdown on Earth.

However, it wasn’t the injection burn at the Moon which created the near fatal experience. In fact, they never made that burn. Instead a simple request from Mission Control two days into the flight, on Monday April 13, changed the fate of the mission and the crew.

Sy Liebergot was a flight controller, specializing as the Electrical, Environmental, and Consumables manager, or more simply, the EECOM. Sy said, “That was the last hour of our eight-hour shift, and under the heading of ‘No Good Deed Goes Unpunished,’ because of some failures we’d had with the quantity readout on oxygen tank number 2 earlier in the mission, I decided I wanted an extra stir of the cryogenic system so we could get an accurate readout.” Sy called up to the spacecraft and requested the crew stir the tank. The reaction was almost instantaneous when the switch was thrown. The tank blew up, and the shrapnel of the disintegration destroyed everything in the immediate vicinity inside the Service Module, exploding contents of an entire side of the module out into space.

“A long string of events took eight years to make this problem,” Sy went on to explain. While still on the launch pad, “an ill-advised, ill-conducted de-tanking procedure subjected that tank to 1,000 degrees Fahrenheit for ten hours. Then, they decided to do it twice! The wiring inside that tank was toast, just waiting for a little spark.” In retrospect, he chided himself for requesting the stir which created that spark, “I didn’t have to ask for those data, but I did because engineers want data. So the last hour of my shift became the longest hour.”

Apollo 13 film
From the left: Bill Paxton as Fred Haise, Kevin Bacon Jack Swigert as and Tom Hanks as Jim Lovell in the film “Apollo 13.” Credit: Universal Pictures
From the left: Bill Paxton as Fred Haise, Kevin Bacon Jack Swigert as and Tom Hanks as Jim Lovell in the film “Apollo 13.” Credit: Universal Pictures

Jim Lovell had been floating through the access tunnel between the Lunar and Command Modules when he heard the bang associated with the explosion. The entire spacecraft began to rock back and forth because of the force of what had happened, along with the subsequent reaction jet firings to try and stabilize the now stricken vehicle. Lovell said the first crewmate he saw was Fred Haise. “I looked to Fred to see if he knew what was causing all the commotion. I could tell by his expression that he had absolutely no idea.” Then Jim saw Jack Swigert, “And Jack’s eyes were as wide as saucers. Not only did he not know what was going on, he was saying to himself, ‘Why am I here?’” Lovell laughed as he said this because Jack had been a last minute replacement for Ken Mattingly, who had been exposed to measles. Swigert became a part of the Apollo 13 prime crew just four days prior to launch. Lovell continued, “Now, if you’ve seen the movie ‘Apollo 13’ you might think that Jack was not really prepared for that flight. It looked like he had to earn his wings every day. But that was wrong. Jack was a very competent astronaut, and if we had to pick a substitute for Ken Mattingly, Jack was the man to take. As a matter of fact, he helped design the [Command Module] malfunction procedures, so we were very happy to have him.”

Fred Haise summed up what was happening in the first few minutes aboard the spacecraft with a single word: “confusion.” He said, “There were lots of lights on from different systems that had no relation to each other… it didn’t make sense. And I think that confused Mission Control, so they thought it was an instrumentation problem, because it did not correlate that any one thing could cause that many lights from different systems at the same time.”

NASA Flight Director Gene Kranz
Gene Kranz, flight director during the Apollo 13 mission. Credit: NASA

Flight Director Gene Kranz agreed. “When I got the call from the spacecraft, we had a master alarm, main bus undervolt, etcetera. I didn’t think too much of this at the time because we’d had two electrical glitches earlier in that shift. I thought this was another glitch and we’ll work it as soon as we get the crew asleep. This went on for about sixty to ninety seconds, then I got a call from Mike Willoughby the GNC [Guidance, Navigation, and Control manager], and he said there was a pretty big bang associated with this. About twelve minutes into the episode, Lovell indicated that he saw something venting, so this went from an easy problem… to all of a sudden it’s survival. It was time to kick this team into survival mode. It took us about fifteen minutes to get our act together on the ground, and it was a pretty tough fifteen minutes.”

Haise understood very quickly that they were in deep trouble. “Several meters were down at the bottom of the gages. They were different sensors, which made a system failure unlikely. I knew we’d lost [oxygen] tank 2, and got a sick feeling in my stomach. I knew we had lost the landing within the first minute.” This was what the crew had been working toward their entire careers as astronauts, to land on the Moon. A huge disappointment to be sure, but those thoughts quickly fell away as everyone geared up for the seemingly insurmountable task of getting back to Earth safely.

The idea of using the Lunar Module as a lifeboat was the critical connection. At first the thoughts were about how to save the Command Module, but those systems were failing fast. If they had already been in orbit around the Moon, and especially if the landing had already taken place, the Command Module could not have sustained the crew to get them home. As Sy Liebergot stated emphatically, “It turns out that the best time for that failure to occur was when it did, because we hadn’t used any of the [Lunar Module] supplies yet.”

The oxygen was the most critical item, and that had to be scrubbed to keep the exhaled carbon dioxide at safe levels. This brought up one of the most innovative instances in the rescue mission. They needed the lithium hydroxide scrubbers in the Command Module to give them enough clean oxygen in the Lunar Module to make it home. However, those canisters were the wrong shape: one was round and the other square. Using items the engineers in Houston knew were on board the vehicle in space, they came up with a way to create a compatible system. One of the critical components of that kludged-up system to hold it all together, and save the lives of the crew, was duct tape. Apollo 17 commander Gene Cernan put it succinctly: “Duct tape, don’t leave home without it!”

The innovative work done throughout the mission to get the crew home safely proved the value of training for contingencies, and simply hiring some of the best young engineers on the planet. Jim Lovell praised everyone involved, and summed up by saying, “If we waited for some miracle, we’d still be up there.”

Sy Liebergot explained just what a close call this was: “We ended the mission with about ten hours of water and ten hours of battery power, so there was no room for error. We really got lucky on that one.” The Apollo Command Module, nicknamed “Odyssey,” splashed down in the Pacific Ocean on April 17, four very long days after the oxygen tank exploded.

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At the time of the Apollo 13 mission it seemed the world saw it as a failure. NASA even lent the Command Module to the French for display at the Musee de l’Air in Paris, seemingly so as not to be reminded of the failure by having it in the United States. However, in 1995, with the release of the movie Apollo 13, based on Jim Lovell’s book Lost Moon, the perception of the mission changed radically. I asked Jim Lovell about this when we spoke in San Diego. “People were getting complacent,” he answered. “It’s like going to a [car] race, and there’s no accidents, so people sit back and drink beer. All of a sudden, Apollo 13 had an explosion, therefore the interest was renewed. When the movie came out twenty-five years after the actual incident, young people [weren’t aware] because they weren’t born when it happened. [This movie] gave them an incentive, a resurgence of the idea of space, and a whole new generation said ‘Hey, let’s go back to the Moon.’ In that respect, NASA thought people had ho-hummed [the mission], but when the movie came out, that changed. Ron Howard did an excellent job.”

Now, the mission of Apollo 13 is considered one of the greatest achievements in our human spaceflight program. The people at NASA and the three astronauts in space, came together to create a survivable scenario against what many felt initially were impossible odds. When Gene Kranz was told it could not be done, he said one of the most famous lines in space history, “Failure is not an option.” He and his team lived those words every day they worked at NASA.

After the discouragement surrounding the mission of Apollo 13 changed to optimism following the release of the movie in 1995, the Command Module Odyssey was finally brought home to America, where she now proudly resides at the Kansas Cosmosphere. Unfortunately, the Lunar Module, Aquarius, which made survival possible for Lovell, Haise, and Swigert as they swung around the Moon, was left in space. It burned up upon reentry, its remains falling into the 35,000 foot deep Tonga Trench in the South Pacific Ocean.

Ms. Evans is the author of The X-15 Rocket Plane, Flying the First Wings into Space. University of Nebraska Press, 2013.