Human error stemming from space engineers using two sets of measurements -- one utilizing miles and the other kilometers -- caused the loss of the Mars Climate Orbiter spacecraft costing $125 million. The review board said that in making a key change to the spacecraft's trajectory one team used the English, or avoirdupois, system of measuring, which utilizes miles, yards, feet and inches as well as pounds and ounces, while the other was using metric kilometers, meters, kilograms and grams.
In a statement, the Jet Propulsion Laboratory said, ``This information was critical to the maneuvers required to place the spacecraft in the proper Mars orbit.'' There are 1.6 kilometers to a mile and 1.1 yards in a meter, while there are 2.2 pounds in a kilogram. At the time the spacecraft was lost, Mars Climate Orbiter Project Manager Richard Cook said scientists had expected that the orbiter would approach Mars at an altitude of between 87 and 93 miles when it fact it came in at 37 miles above the surface of the planet. He said the minimum survival altitude was 53 miles. Jet Propulsion Laboratory Director Edward Stone said, ``Our inability to recognize and correct this simple error has had major implications."