A Successful Failure

Behind the production and rescue: the science of the Apollo 13 

Apollo 13, directed by Ron Howard in 1995, was one of the biggest hit movies of its time. Its popularity grew not only because of its superstar cast including Tom Hanks, Bill Paxton, Ed Harris, and Kevin Bacon, but also for telling the true story of the Apollo 13 rescue mission with contemporary CGI and realistic portrayals of action in space. While many people have seen this famous movie, not everyone knows how dire the true situation was. NASA and the Apollo mission faced many major difficulties and displayed unprecedented levels of ingenuity to overcome them and save the crew. 

The rescue mission began with a small mistake: the second oxygen tank onboard Apollo 13 was dropped during a maintenance check before the flight. Although it passed all its subsequent tests before the crew’s departure on April 11th, 1970, the internal insulation of the wires inside the tank were damaged, leading to the disastrous possibility of a fire from a spark in pure oxygen (1). 

An image of the final flight path of Apollo 13, showing the free-return trajectory they followed. 

This threat was exactly what happened on the 56th hour of a planned 10-day trip. During a routine cryo-stir, a common procedure to mix the cold layers of oxygen, the damaged wiring caused a spark within the pure oxygen, causing a fire and leading to the explosion of the No. 2 oxygen tank (2). This combustion would spark a chain reaction of problems: damaging the 1st tank of oxygen, depriving the crew of power within the command module (CM), and requiring the three astronauts to live the next 90 hours in the lunar module (LEM) (1).

Due to the major power failures resulting in the shutdown of the command module, the mission to the moon was scrapped and all efforts were directed to the rescue of its crewmembers. Because of the lack of power and the need to conserve leftover fuel, mission control in Houston decided to use the moon’s orbit to slingshot the crewmembers back to Earth, called the “free-return trajectory” (3). Without the capabilities of the engine in the command module, the crew instead made a 35-second burn using the propulsion from the LEM’s descent engine (used to previously land on the moon) to position themselves in the moon’s orbit (4). Later on, they would propel themself out of lunar orbit back on their way to Earth. 

Despite the success of being on a trajectory back to Earth, the three astronauts faced another upcoming issue in the cramped LEM: power depletion and rising CO2 levels. The LEM was previously built for the trip down to the moon and was designed to support two astronauts for 48 hours, not three crew members for 90 hours. As a result, the men were required to shut down any non-essential systems, including lights, heaters, and guidance systems (5). These power-saving methods were laborious to the astronauts: their water lines froze, they lost their appetites, and they could not sleep for days. As they went longer in the LEM, CO2 levels increased to poisonous levels. Though they had unused filters in the CM, those filters were meant to be plugged through a square hole, differing from the LEM’s system which required a circular hook-up. Luckily, through the hard work of the NASA engineers down in Houston, they were able to improvise an adapter “mailbox” using floating materials in their ship such as cardboard, duct tape, a plastic bag, and a hose to connect the scrubbers to the LEM, regulating their CO2 levels (3). 

A photo of the “mailbox,” a contraption that they improvised to counteract the rising levels of CO2. 

As a result of all these improvised fixes, the relentless efforts of mission control and the engineers down on Earth, and the strength of the crew, the three men were able to return down to Earth. Not only was this rescue mission the epitome of space travel, but it was truly one of the greatest testaments to teamwork. 


  1. Pruitt, S. (2020, April 2). What Went Wrong on Apollo 13? HISTORY. https://www.history.com/news/apollo-13-what-went-wrong
  2. Apollo 13: the story behind NASA’s rescue mission. (2020). Skyatnightmagazine.com. https://www.skyatnightmagazine.com/space-missions/apollo-13-story-nasa-rescue-mission
  3. Apollo 13. (2014). The Planetary Society. https://www.planetary.org/space-missions/apollo-13#:~:text=Working%20closely%20with%20mission%20control,for%20re%2Dentry%20and%20splashdown
  4. Hailwood, A. (2019, July 18). Apollo 13… a close call for NASA… and Omega. Revolution Watch. https://revolutionwatch.com/apollo-13-a-close-call-for-nasa-and-omega/#:~:text=The%20first%20step%20after%20the,Lunar%20Module%20Descent%20Propulsion%20System
  5. George, A. (2020, April 8). How the Crew of the Damaged Apollo 13 Came Home. Smithsonian Magazine; Smithsonian Magazine. https://www.smithsonianmag.com/smithsonian-institution/fifty-years-ago-apollo-13-crew-came-home-180974607/ 


  1. https://www.skyatnightmagazine.com/space-missions/apollo-13-story-nasa-rescue-mission.
  2. https://www.smithsonianmag.com/smithsonian-institution/fifty-years-ago-apollo-13-crew-came-home-180974607/.