NASA offers little hope for wayward Mars probe

December 6, 1999
Web posted at: 4:13 a.m. EST (0913 GMT)

In this story: NASA assumes craft came down safely Lander's loss would be a double blow RELATED STORIES, SITES

From staff and wire reports

PASADENA, California (CNN) -- NASA offered little hope of making contact with its wayward Mars Polar Lander on Monday after the craft missed a sixth opportunity to contact its controllers on Earth.

After more than an hour of searching late Sunday brought little more than static from the red planet, project director Richard Cook said an early-morning attempt to contact the Mars Polar Lander Tuesday would be "the last high-probability attempt that we have."

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"We're pretty much reaching the point where we've used up the final silver bullets," he said. Earlier Sunday, after three days of fruitless attempts to reach the $165 million spacecraft, Cook conceded the possibility that the lander may not have landed intact.

The space probe was supposed to signal NASA's Jet Propulsion Laboratory in Pasadena after its scheduled landing Friday. The next chance NASA has to receive any signal from the lander will be at 12:20 a.m. Tuesday PST (3:20 a.m. EST).

"The sense of the teams is that the odds of success will diminish greatly after tomorrow night," Cook said. JPL controllers will make another attempt at 11 p.m. Tuesday, he said, but "I think the likelihood of seeing anything from that search is not great."

Mission managers worked on eliminating simple failure scenarios one by one. But they said if contact has not been established before mid-week, it was increasingly unlikely that successful contact would be made.

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The Mars Polar Lander was to have landed about 500 miles (800 kilometers) from the planet's south pole Friday afternoon. The lack of any signals left mission officials with hope only that the craft survived the touchdown and, on its own, was taking steps to establish contact.

Controllers have operated on the assumption that the landing was successful because the lander was in excellent condition just prior to entry and analysis showed its trajectory was good.

"I think until Tuesday, we still have a reasonable chance that we landed successfully and we're in some mode that we're trying to get ourselves out of," Cook said. "After Tuesday I think you really have to question whether or not the entry and landing occurred successfully."

Controllers are also increasingly pessimistic about the fate of two tiny probes designed to fall separately from orbit and plunge to the surface. They also have failed to send signals.

The piggyback mission, called Deep Space 2, cost cost an additional $30 million for design, construction, operation.

"I think if we haven't heard from them in the next 24 hours we will have exhausted most of our options," Sarah Gavit, project manager for the Deep Space 2 probes, told reporters Sunday afternoon.

Engineers have theorized that the Mars Polar Lander set down in a position that has kept its dish antenna from pointing at Earth, or that it settled into a soft surface.

NASA said that if the communications blackout continued past the weekend, commands would be transmitted to instruct the lander -- if it was operational -- to begin switching back and forth between different systems to try to signal Earth.

The lander also was programmed to keep track of how long it has been since it was last contacted by Earth, and after six days to assume there was some type of failure and begin switching between backups on its own.

A lander failure would be a double blow to the JPL, which is still recovering from the September loss of the lander's sibling spacecraft, the Mars Climate Orbiter.

The orbiter was lost due to a mathematical error: Engineers failed to convert key figures in a key navigational program to their metric equivalents, causing the craft to miss its planned orbit and burn up in the thin martian atmosphere.

The Associated Press and Reuters contributed to this report.