Mars Orbiter

Failure to convert English measures to metric values was the root cause of the loss of the Mars Climate Orbiter, a spacecraft that smashed into the planet instead of reaching a safe orbit, a NASA investigation concluded Wednesday.

See http://edition.cnn.com/TECH/space/9909/30/mars.metric/

See also: UnearthlySoftware

When ArianeFive bought the farm BertrandMeyer tried to showcase it as an example of failure due to lack of DesignByContract.

Mightn't we fault JPL not for avoiding BigDesignUpFront, but for not RelentlessTesting? --PCP

I wouldn't say it was that. It wasn't that they didn't test. It was more that they tested incorrectly. The problem was that they used the Ariane IV test environment to test Ariane V, but the physics of the rocket had changed.