Mars Orbiter’s Demise Avoidable
by Michael Cabbage of The Sentinel Staff
CAPE CANAVERAL — The sort of mistake usually found in grade-school math homework proved fatal to a $125 million NASA Mars probe.
A NASA investigation released Wednesday confirmed earlier reports that aerospace contractor Lockheed Martin botched the design of critical navigation software for the ill-fated Mars Climate Orbiter. While flight computers on the ground did calculations based on pounds of thrust per second, the spacecraft’s computer used metric system units called newtons. A check to make sure the values were compatible was never done.
The spacecraft was to go into orbit around Mars on Sept. 23, acting as a weather satellite and relaying data to Earth from a sister probe scheduled to land on the Red Planet next month. But the metric mistake caused the Climate Orbiter to drift slowly off course as it fired its rocket engines about a dozen times to stabilize itself during a nine-month, 416-million mile journey. The probe approached Mars at too low an altitude and likely burned up in the planet’s atmosphere.