September 24, 1999
Web posted at: 4:13 p.m. EDT (2013 GMT)

By Robin Lloyd
CNN Interactive Senior Writer

(CNN) -- NASA will call off its search Friday for a $125-million spacecraft lost at Mars after a navigation error pushed the probe fatally close to the planet.

Engineers have been using NASA's Deep Space Network of radio antennae to search for a signal from the Mars Climate Orbiter ever since it plunged more deeply than planned into the martian atmosphere early Thursday.

It was unclear if the spacecraft survived the dangerous dip into the atmosphere or burned and crashed on the planet, although the latter scenario is more likely given its steep descent.

Richard Cook, center, explains the whereabouts of the Mars Climate Orbiter that is presumed destroyed. A preliminary analysis shows the satellite approached Mars too closely and likely broke into pieces or burned up in the atmosphere.

Either way, unless the craft turns earlier, the search will be called off at 6 p.m. EDT because NASA believes it is very unlikely that the satellite will be found, said an agency spokesperson, who spoke with CNN Interactive on the condition of anonymity.

Competition for missions to get time on the Deep Space Network is intense, but NASA obtained time using the network's powerful 70-meter dish. Once that period of time is exhausted, the search will be abandoned, the spokesperson said.

The news will be announced officially later Friday. Climate Orbiter was designed for a Mars weather-watching mission and to relay signals from upcoming lander missions to Earth.

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The steering problem existed for a week before the craft approached Mars, but engineers were unaware of it as Climate Orbiter drew close to the planet. The spacecraft correctly fired its engine for 16 minutes Thursday to set itself up for orbit around Mars.

But after the firing, NASA never heard from the spacecraft again.

The trouble likely was the result of human error in sending a bad command to Climate Orbiter or a problem with the radio or digital transmission of commands.

"It potentially resulted in the loss of the mission," said Richard Cook, manager of the Mars Surveyor '98 program, which includes Climate Orbiter, on Thursday.

The probe came within 60 km (36 miles) of the planet -- about 100 km closer than planned and about 25 km (15 miles) beneath the level at which the spacecraft could survive, mission members said.

The spacecraft was well built by Lockheed Martin and cannot be blamed for the loss of the mission, said project manager John McNamee.