In 1999, NASA's Mars Climate Orbiter completed a flawless 669-million-kilometer journey only to be destroyed in its final moments by one of the most infamous errors in engineering history: a unit conversion mismatch. This episode looks past the textbook punchline to examine the deeper, more frustrating reality of why the error was never caught, even after navigators noticed something was wrong.

We set the scene with NASA's 1990s "faster, better, cheaper" mandate that stripped margins from a bargain-built spacecraft, then follow the probe's perfect launch and the dangerous aerobraking maneuver it never got to complete. The fatal flaw traced to ground software outputting pound-seconds while NASA's system expected newton-seconds, an error compounding over every thruster firing. Worst of all, concerns were dismissed because the right paperwork  ...