Math Mistakes in History: The Mars Climate Orbiter


Mars photo by NASA and the European Space Agency

On December 11, 1998 the Mars Climate Orbiter was launched from Cape Canaveral, Florida. Ten months later, on September 23, 1999, NASA lost touch with the Climate Orbiter just as it was approaching the red planet. They never regained communication, and the $125 million spacecraft was considered a complete loss. The problem? Unit conversion.

Several teams had been working on the project. According to CNN, NASA had been working in metric units for several years. One of the teams working for a contractor, however, used English units (pounds, miles, inches, etc.), and the lack of conversion meant that the Climate Orbiter approached Mars from an altitude of 60 kilometers (37 miles) instead of 150 kilometers (93 miles).

The moral of the story: check your work, and pay attention to units.

(As a footnote, just the past January, NASA announced that it would use metric for all its operations related to the upcoming missions to the moon in order to make it easier to cooperate with other space agencies. Burma and Liberia are the only other countries that still primarily use English units instead of metric.)

Mars photo created by NASA and the European Space Agency

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4 Responses to “Math Mistakes in History: The Mars Climate Orbiter”

  1. seveneleven Says:

    Something we are lectured about remembering forever!

  2. Polygons on Mars « 360 Says:

    […] Polygons on Mars The Phoenix Mars Lander arrived safely on Mars Sunday night! This is a particularly big deal because the previous Lander didn’t: the Mars Polar Lander was due to arrive on Mars in December 1999 but, for still-unknown reasons, communications stopped suddenly about 6 minutes before it was due to enter the Martian atmosphere and its exact whereabout remain unknown. (Incidentally, the Polar Lander was part of the Mars Surveyor mission. The other part was the Mars Climate Orbiter, which ran into a little $125 million problem of its own when the teams didn’t translate between imperial and metric units.) […]

  3. The art of Haiku applied to computer programming « Thoughts From The Heart On The Left Says:

    […] As it turns out, the error that I was thinking about was not a coding problem but a conversion problem; the Mars Climate Observer was launched on December 11, 1998 but was lost sometime around September 23, 1999.  Examination of the records showed that one of the contractors had used English units in a calculation while other calculations were done with metric units.  As a result of the failure to convert miles to kilometers, a $125 million dollar satellite was lost.  (see “Math Mistakes in History: The Mars Climate Orbiter”) […]

  4. How many grams in an ounce? | 360 Says:

    […] between units can be hard, as seen before (and before and before).  Fortunately, food containers often include both English units and Metric units.  […]

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