From space.com

Mars Global Surveyor Could Shed Light on Polar Lander's Fate

PASADENA, Calif. - NASA plans to use the high-resolution camera aboard the Mars Global Surveyor to hunt for traces of the Polar Lander on the surface of the Red Planet.

NASA has not heard from its Mars Polar Lander since seven minutes before it plunged into the Martian atmosphere on Friday. That silence now seems permanent.

That leaves the space agency without any data that could shed light on what could have gone wrong during the $165-million spacecraft’s entry, descent and landing on Mars.

By training the Global Surveyor’s Mars Orbiter Camera on the most likely area where the lander touched down, NASA hopes to see perhaps the spacecraft itself, if not its heat shields and descent parachute. The camera could also conceivably spot an area of disturbed soil made by the descent rockets’ wash during landing.

If the spacecraft made anything other than its planned soft landing, it would be even easier for the camera to locate any resulting impact crater.

Richard Cook, the Polar Lander’s project manager, said the mission team was beginning to work on a plan to have the Global Surveyor scan the landing region.

"It’s a couple of weeks off," Cook said.

What the Global Surveyor’s camera will look for depends on what NASA wants it to look for, said Michael Malin, of Malin Space Science Systems, the San Diego-based builder of the instrument.

"If there were a catastrophic failure prior to touchdown, there would be a big hole in the ground," Malin said. "If the failure occurred after touchdown, we might not see much."

The high-resolution camera can see objects as small as 5 feet (1.5 meters) across. That means it could see the spacecraft’s heat shield or parachute - if NASA knew where to look. Any search would rely almost on guesswork, like calculating the trajectory of a leaf fluttering to the ground.

In the case of the spacecraft itself, NASA has made refined calculations of where it landed within a tight area.

Malin said the landing area could be as small as 9 by 25 miles (15 by 40 kilometers).

However, it would take the Global Surveyor as long as 50 days to assemble a patchwork quilt of images of that area.

One explanation for the silence from the lander and its two companion microprobes is that the spacecraft’s cruise stage failed to separate 10 minutes before landing.

If that were the case, all three spacecraft would have fallen to Mars along a trajectory far different than that they would have taken during a normal entry and descent to the surface. That would place their impact crater far from the targeted landing site.

However, one mission official said the Global Surveyor would first search under the assumption the lander made it safely to the surface.

"What we would want to do is have the Mars Orbiter Camera look at the most likely landing site, of course assuming the landing occurred nominally," said Phil Knocke, the Mars Polar Lander mission engineer.

Malin said the odds of using the Surveyor to spot the Deep Space 2 microprobes, which also vanished after landing on Mars, were even slimmer.

"I don’t think we would have much a chance, but we’ll try if asked," Malin said.