The Theme of History in Stoichiometry

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The Chemistry of Apollo 13

One of our favorite historical movies here at Shmoop is Apollo 13. If you haven't seen it, check it out. Make sure you also have a box of tissues. Not only does it pull at our heart strings, but it combines science, chemistry, and human ingenuity. Can you name any other movie that can combine those three elements and win tons of awards (including a few Oscars)? We didn't think so.

The movie is based on the real story of NASA's ill-fated trip to the moon in 1970. After two seemingly uneventful days on its way to the moon, an electrical short caused two of the oxygen tanks mounted on the outside of the spaceship to explode.⁷ In response to the explosion, the pilot, Jack Swigert, radioed ground control with the now famous line, "Houston, we've had a problem here."⁸

Apollo 13 Pilot, Jack Swigert.

The fact that the oxygen tanks exploded was bad news for the spaceship and its crew. Not only did the astronauts need it to stay alive, but it was also combined with hydrogen to make water and much needed energy for the ship. The mission to land on the moon was aborted and getting back to Earth safely became the primary objective.

The crew was ordered to shut down all non-essential electrical instruments and told to breathe as little as possible. As if, right? The crew was also asked to move to the smaller Lunar Module attached to the ship. Unfortunately the "CO₂ scrubbers" in the Lunar Module were not fully functional thanks to some ill-fitting parts. These devices helped remove CO₂ from the atmosphere of the ship by reacting LiOH with CO₂ to make Li₂CO₃ and H₂O. The removal of the CO₂ was essential because high carbon dioxide levels in the blood are toxic, preventing oxygen from reaching cells.

2 LiOH + CO₂ → Li₂CO₃ + H₂O

Where was the CO₂ coming from? The astronauts themselves. During the process of breathing (respiration to be exact) O₂ is converted to CO₂:

O₂ + [CH₂O] → CO₂ + H₂O + energy

To make a long story short, ground control in Houston was able to get the "CO₂ scrubbers" fully functional and the crew was able to conserve enough oxygen, water, and energy to reenter the Earth's atmosphere safely.^7,8

The Crew of the Apollo 13

The Apollo 13 mission and near-disaster is an important lesson in life stoichiometry. All reactions have consequences. Breathing consumes oxygen. Respiration forms carbon dioxide. In chemistry and in life we need to be aware of the perfect balance of chemistry all around us!