The launch was mostly without incident, save for an anomaly that cause the inboard second stage engine to shut down two minutes early. The outboard engines and the third stage engines were burnt a bit longer to compensate and, afterward, nothing seemed terribly amiss. The crew repositioned their module, Odyssey, so as to be properly docked to the lunar module, Aquarius, then ditched the spent third stage of the rocket and started on their three-day journey to the moon.
The evening of the second day of their flight, the crew of Apollo 13 broadcast live to viewers on Earth, giving folks back home a look at the inside of Odyssey and Aquarius. They were on air for about fifty minutes before wishing folks planet-side a pleasant evening. While the lunar module pilot was powering down Aquarius and the mission commander was stowing the camera away, mission control requested that the command module pilot stir the cryo tanks. Two minutes after turning the tank fans on, the crew heard a loud bang, the power started flickering, and the attitude thrusters randomly fired. Jack Swigert, the command module pilot, radioed mission control: “Houston, we’ve had a problem here.”
Fight commander Jim Lovell repeated the announcement and clarified—“main B bus undervolt”— one of the module’s main electrical circuits experienced a temporary loss of operating voltage. Fred Haise, the lunar module pilot, then reported that the voltage readouts seemed to have recovered and mentioned to mission control the “pretty large bang associated” with the warning and alerts triggered by the malfunction. One of the two oxygen tanks immediately read as empty and, moments later, two of the spacecraft’s fuel cells failed. Lovell reported observing gas escaping into space. Over the next few hours, the oxygen in the other tank depleted, forcing the shut-down of the final fuel cell which generated power by combining oxygen and hydrogen into water. The command module was left with only a limited battery. Since the command module was the only part of the spacecraft equipped for Earth reentry, the crew shut the module down to preserve what power it had for the return home and moved to the lunar module which, since the incident scuttled the lunar landing, became the crew’s lifeboat.
Moving into the lunar module came with its own host of problems, not the least of which being the complication to existing mission abort plans. The quickest of the plans would require jettisoning the lunar module, which was, at this point, out of the question. Another of the plans would require the command module to separate from the service module which, though damaged, provided a desired layer of thermal protection it offered the command module. Ultimately, Gene Kranz, the lead flight director in Houston, opted for a third option that would, hopefully, conserve power and buy everyone more time to plan before any major rocket burns that may or may not have threatened the craft’s structural integrity: Apollo 13 would use the moon’s gravity as a speed boost to slingshot back to Earth.
Consumables were another challenge: the lunar module, built to sustain two people for about thirty-six hours, had to support three people for four days. Of particular concern was water, which was needed both for drinking and for cooling equipment. The crew rationed their water intake to six ounces a person per day—about twenty percent of normal intake—and supplemented with fruit juices and ate wet-pack foods. The three crewmembers lost a combined total of thirty-one pounds in the course of four days. They also became severely dehydrated—Haise developed a UTI that turned into a kidney infection that caused him constant pain for the remainder of the flight. Supplies of lithium hydroxide, which was used to scrub carbon dioxide from the module’s atmosphere, was another pressing issue. The lunar module was not equipped with enough LiOH to sustain the crew for the duration of their return home. The command module had more than sufficient supplies, but those cubical canisters were not compatible with the lunar module’s cylindrical canister-sockets. Engineers on the ground devised “the mailbox,” an improvised adapter—made whatever there might be spare bits of on the space craft: socks, flight manual covers, etc.—that joined the mismatched canisters and canister-sockets by drawing air through them using a return hose from one of the space suits.
Completing a full power-up of the command module after a total shutdown was another pertinent issue to be addressed, as it had never been attempted while in flight—it wasn’t something that was even intended to be done during flight. This was further complicated because of the cold: reduced power levels in the lunar modules meant much lower temperature and water began condensing on the surfaces of the completely unpowered command module, causing concern about a short-out during power-up. Ultimately, an entirely new procedure for power-up was devised that took into account the limited time and power supply with which the crew had to work. The final critical issue to be addressed was finding a way to separate the lunar module from the command module that provided safe distance for reentry. Normally, this is something that would be done using a service/command module system, but because of the explosion, the service module was to be jettisoned before the lunar module. By pressurizing the tunnel between the lunar and command modules just the right amount—too little and they would remain too close, too much could damage the hatch and cause the astronauts to burn up during reentry—just prior to separation provided enough oomph to ensure a safe distance between the two modules.
It wasn’t until the crew was preparing for reentry that they were able to get a look at the damage to the service module—as they jettisoned the module and moved a safe distance from it, they could see that an entire panel had been blown off the side of the module, leaving the inside exposed to space. They then jettisoned the lunar module and began Odyssey’s reentry sequence. A lunar mission’s reentry was usually accompanied by a four-minute communications black out—Apollo 13 black out last more than six minutes. Radio contact was reestablished when the capsule splashed down in the South Pacific, just a little over six miles away from the recovery ship, the USS Iwo Jima.
Save for Haise’s severe urinary tract and kidney infections, the crew was recovered in good health. All three crew members remained at NASA for some years after the incident. Swigert went on to run for office and was elected to the U.S. House of Representatives, though he passed away less than two months after his election. Lovell and Haise—both octegenarians—are still alive and kicking. Haise, in his role as a test pilot in the years after that ill-fated flight, was instrumental in getting NASA’s space shuttle program off the ground. Lovell has written a book about the Apollo 13 disaster, Lost Moon, upon which Ron Howard’s 1996 film Apollo 13 was based. Lovell actually has a cameo in the film, playing the USS Iwo Jima’s captain.
On this forty-seventh anniversary of the launch of Apollo 13, the story, the crew, the engineers on the ground, and even Odyssey itself continue to serve as reminders of human ingenuity and resilience, as well as the embodiment of the mission’s motto: Ex Luna, scientia. Though it may not be the knowledge anyone wanted or anticipated learning, there was a great deal of knowledge gained from Apollo 13’s incredibly successful failure. Thank you.