Originally Posted by Davezorz
Also didn't NASA lose a mars lander to improper conversion more recently than the above stories?
The '99 Mars Climate Orbiter. And it wasn't supposed
to land. That was the problem.
Background on failure:
Lockheed Martin, who build the spacecraft and its launching system, did everything in SAE units.
NASA JPL, like all right-thinking organizations, works in SI units.
Two different pieces of software, running on the ground, were used to compute thruster firings during the leadup to orbital insertion around Mars. One used SI units (newton-seconds), the other SAE units (pound-seconds) in specifying the required thrust to achieve the desired attitude and trajectory corrections.
Needless to say, data was transcribed directly from one system into the other without the required correction, and then uploaded to the spacecraft, leading to an improper thruster firing which caused the probe to plunge directly into the Martian atmosphere rather than achieving a stable orbit.