@wendinoakland @renwillis @Natasha_Jay @stux
NASA lost the Mars Climate Orbiter in 1999 due to a fatal mix-up between English (feet, pounds) and metric (meters, Newtons) units, where contractor software used English measurements for thruster force while NASA expected metric, causing the orbiter to enter Mars' atmosphere too low and burn up, a classic example of unit conversion error.
Mars Climate Orbiter - NASA Science
Designed to study Mars from orbit and serve as a communications relay for the Mars Polar Lander and Deep Space probes, the Mars Climate Orbiter was unsuccessful due to a navigation error; an investigation found that the spacecraft burned up in Mars' atmosphere.
NASA Science (science.nasa.gov)
$327.6 million 