Fifty years ago this week, an explosion on the Apollo 13 moon mission stranded three astronauts hundreds of thousands of miles from home. You probably know that Fred Haise, Jim Lovell, and Jack Swigert made it home safely (water landing shown, with two of the astronauts in white). You may not know the chemist behind the rocket engine that saved them, which began its life as an apparatus for measuring chemical reaction rates. This bonus episode of Stereo Chemistry tells the story of the engine’s design with help from two of the people who created it. Listen now to a tale that starts with an explosion and ends with SpaceX’s pioneering reusable rockets, with one small step for a man along the way. CORRECTIONS: This episode was updated on April 15, 2020, to reflect that Fred Haise, not Ken Mattingly, flew aboard Apollo 13. On April 22, 2020, this podcast description was also corrected to reflect Haise's role and clarify that the photo shows only two of the astronauts.   To learn more about the chemistry of rocket fuel, check out Ep. 23 of Stereo Chemistry: https://cen.acs.org/physical-chemistry/astrochemistry/Podcast-rocket-chemistry-blasted-off/97/i42 Image credit: NASA