MEasure for mEasure.(metric system)

Early on the morning of September 23, 1999, engineers at NASA's Jet Propulsion Laboratory lost contact with a Dumpster-size probe called the Mars Climate Orbiter. According to a news-service report, the mission's increasingly anxious flight-operations manager "alternated between staring at his monitor, staring at flight plans and pulling at his wedding band." A few days later, investigators found the problem: the orbiter reported its thruster firings in newtons, the metric system's unit of force, while navigation software at ground control used pounds. The cumulative error was small--roughly a hundred miles on a journey of more than four hundred million miles--but it ...