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NASA SAYS FAULTY MATH DOOMED THE MARS CLIMATE ORBITER "NASA lost its $125 million Mars Climate Orbiter last week because one set of engineers was working with metric measurements while another set worked with English measurements, officials said Thursday," September 30, 1999. "The error caused the spacecraft to fly too close to Mars, where it either burned or broke up, just as it was beginning to orbit the planet after a nine-month trip through space." "Two teams were responsible for determining the spacecraft's course. One was at Lockheed Martin in Denver, which built the craft, while the other was at NASA's Jet Propulsion Laboratory in Pasadena, which controlled it." "In plotting the course for (Mars) Climate Orbiter, Lockheed used English measurements-- standard for (USA) spacecraft builders--and passed them on to JPL. But JPL either assumed the figures were already in metric terms or somehow failed to make the conversion for them." "'Somewhere the translation got lost,' said Doug Isbell, a NASA spokesman." "The error was embedded in the orbiter's software from the beginning, NASA said, but was not apparent to controllers until too late." "At issue was a critical calculation for the orbiter's thrust (which Mars Climate Orbiter needed to drop out of its flight path into a safe orbit around Mars--J.T.). Lockheed used an equation relying on pounds and feet while JPL wanted it in kilograms and meters." "A kilogram is 2.2 pounds and a meter is 39.37 inches, or just over three feet. The error caused the spacecraft to veer too close-- 37 miles--to the Martian surface. That's well below the 53-mile minimum altitude at which a probe could go and survive. NASA had wanted it to fly no closer than 87 miles." "'People sometimes make errors,' said Ed Weiler, NASA's space science chief. 'The problem here was not the error, it was the failure of...the checks and balances in our processes to detect the error.'" "House Science Committee Chairman James Sensenbrenner (R-Wis.) released a two-word statement: 'I'm speechless.'" (See USA Today for October 1, 1999, "Bad math added up to doomed Mars craft" by Paul Hoversten.) (Editor's Comment: If NASA is so certin that the Mars Climate Orbiter crashed, then why don't they use the Mars Global Surveyor, which is already in orbit, to photograph the crash site? If there is a crash site, and I doubt it. Between the nuclear accident in Tokaimura and NASA losing the Mars Climate Orbiter, it's getting a little hard to feel confident about the outcome of the Y2K situation.)
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