MARS CLIMATE ORBITER DISAPPEARS

On Thursday, September 23, 1999, at 5:05 a.m., scientists at NASA's Jet Propulsion Laboratory in California were monitoring the Mars Climate Observer (MCO) as it began its final approach into orbit around Mars. The Mars Climate Observer was launched from Earth on December 11, 1998. NASA hoped that the $125 million spacecraft "would return the most detailed information yet about Mars' climate and atmospheric conditions."

The MCO passed behind Mars, ready to begin a 17-minute engine burn maneuver that would slow its speed and drop it into a Martian orbit. But, at the moment the spacecraft should have emerged from behind Mars, JPL sent a radio signal and received nothing by way of a response. "We're not quite sure what's happening," said project manager Richard Cook after the MCO failed to answer the signal. "We don't know what specifically happened to the spacecraft," Cook added, "We believe it came in at a lower altitude."

The Mars Climate Orbiter "was last heard from about 5:05 a.m. Thursday after it fired its engine to slow down as it neared Mars. All systems were fine as it slipped behind the planet and out of radio range from Earth." "Controllers thought the spacecraft was on a course to fly no lower than 87 miles (149 kilometers) above the surface on the far side of Mars. That would be low enough to be captured by Martian gravity but high enough to avoid damage from atmospheric friction." "But the spacecraft failed to reappear on the other side of Mars about 20 minutes later when it would have been back in radio range." "Controllers checked their calculations and found that the spacecraft had been on a (flight) path just 37 miles (59 kilometers) above the surface--so close to Mars that atmospheric friction probably burned or shattered it, Cook said." "'We're never had an error like this in the spacecraft business that I could recall,' says Lou Friedman, executive director of the non-profit Planetary Society in Pasadena. 'This is unprecedented, and we'll learn a lot from it.'" "The loss will not hurt Martian exploration in the long run, said Carl Pilcher, NASA's chief of solar systems exploration. The agency plans at least one Mars mission every two years for at least a decade. The same type of instruments aboard Climate Orbiter can be flown on missions planned in 2006 or 2007."

On Saturday, September 25, 1999, at 3 p.m., NASA ended its radio search for the missing spacecraft. The agency had been using the three 70-meter (230-foot) diameter dish antennae of their Deep Space Network in the hopes of re-acquiring a radio signal from the MCO. For now, the Mars Climate Orbiter seems to have met the same dismal fate of the Mars Observer in 1993 and the Pathfinder/Sojourner mission of 1997. (See USA Today for Friday, September 24, 1999, page 6A, "Bad math may have lost spacecraft" by Paul Hovenstern.)