In September 1999 a NASA spacecraft that had flown 416 million miles to Mars was torn apart in the planet’s atmosphere — not by an explosion or bad luck, but by a units mix-up, one team using imperial pounds where another expected metric newtons, the same mistake that strips a bolt in a home garage.

In September 1999 a NASA spacecraft that had flown 416 million miles to Mars was torn apart in the planet’s atmosphere — not by an explosion or bad luck, but by a units mix-up, one team using imperial pounds where another expected metric newtons, the same mistake that strips a bolt in a home garage.

In September 1999, a NASA spacecraft that had traveled roughly 416 million miles to reach Mars flew too low into the planet’s atmosphere and was torn apart, ending a mission years in the making. It was not destroyed by an explosion, a hostile planet, or bad luck. It was destroyed by a unit’s error, the same metric-versus-imperial mix-up that strips a bolt in a home garage, except here it cost a spacecraft. One piece of software reported the orbi…