In an effort to make a third human-crewed lunar landing, NASA tasked three astronauts with carrying out the Apollo 13 survival mission on April 11, 1970. Lunar module pilot Fred Haise and commander Jim Lovell were to descend to the moon’s surface. Meanwhile, command module pilot Jack Swigert would remain in orbit. But on the day of the mission launch, the spacecraft suffered an explosion that made the crew’s demise seem certain.
The crew wasn't new to lunar landings, having been the first to land in the Fra Mauro lunar highlands. This particular area of the moon appeared brighter compared to the flat plains visited by earlier Apollo missions.
As they commenced their daunting mission, the crew failed to notice that one of the oxygen tanks had been damaged from all the testing. The spacecraft builders also missed this potentially fatal fault. To give you a sense of the situation: there were six pie-sliced sectors in the spacecraft's cylindrical service module. Sector 4 held the damaged oxygen tank, but the main fuel tanks were sectors 2, 3, 5, and 6.
The crew only noticed this dangerous issue 56 hours into the Apollo 13 mission. Jack Swigert was immediately instructed to agitate the super-cold liquid oxygen. But just a few moments later, oxygen tank 2 collapsed. The explosion damaged the spacecraft so much that photos taken after the flight showed a side missing!
With the command module rapidly losing power, the astronauts had to move into the lunar module (LM) and use it as a kind of lifeboat. The LM cabin was designed for only two people, so you can imagine how tight they had to squeeze themselves in.
There wasn't enough breathable air to last until they arrived at Earth as the chemical canister was only designed to support two men. The three astronauts had to build a crude adapter through spare parts found inside so they could use cartridges from the command module.
While the air issue may have been solved, their problems were only just beginning. The astronauts had to take the LM back along a path that would allow them to land safely on Earth. They had to act fast to start up the LM's big landing engine so they could get back on track.
Apollo 13 is a shining example of how dangerous NASA missions can be. However, thanks to the ingenuity and perseverance of the three astronauts, all troubles were overcome. The fateful incident had a movie made about it to remind humanity of what we can do if we work hard enough and refuse to give up. Director Ron Howard released Apollo 13 in 1995, starring Jim Lovell and Tom Hanks.