Mars Pathfinder enlisted in search for lost Polar Lander

Mars Pathfinder site, 1998 and 2000 (right).

January 25, 2000
Web posted at: 1:57 PM EST (1857 GMT)

In this story: Finding a needle in a pile of needles Pathfinder test reveals daunting task RELATED STORIES, SITES

(CNN) -- Can a spacecraft that touched down on Mars in 1997 help find the lost Polar Lander? Hoping the answer is yes, NASA has aimed a camera orbiting the red planet on the landing site of the Mars Pathfinder.

Besides providing the highest resolution images ever of the spot -- the space agency released those images this week -- the photo shoot could help scientists focus the lens on the area where the Mars Polar Lander disappeared.

After abandoning efforts last week to make radio contact with the $165 million Polar Lander, which has remained silent since preparing to land in December, NASA said that the Global Mars Surveyor would continue a visual search of the barren polar landscape until late January or early February.

The pictures are taken at the highest spatial resolution possible for the orbiting camera, 1.5 meters (5 feet) per pixel. At this resolution, the fuselage and wings of a jumbo jet can be distinguished.

Is the Mars Lander somewhere in here?

Yet the task of finding the lander is daunting. The spacecraft most likely consists of only a few square pixels within one of the images. Mars scientists are basically trying to distinguish one or two pixels from nearly 150 million.

The search is like "trying to find a specific needle in ... a haystack-sized pile of needles," one team member remarked.

In the first image, ellipses indicate the regions in which the Polar Lander may have touched down. NASA's Langley Research Center derived the largest ellipse; the Mars Polar Lander contractor, Lockheed Martin Astronautics, calculated the two smaller ones. The smallest is the target that was given to the Surveyor camera team shortly after lander recovery attempts began in mid-December.

One mosaic of orbiting camera images offers much higher resolution. In the composite, more than 330 square kilometers (127 sq. miles) of south polar terrain have been imaged at 1.5 meters per pixel.

No trace of the Polar Lander or its parachute has been seen, although this is not surprising given the camera's resolution and illumination conditions, NASA scientists said.

Conducted to determine the capabilities of the orbiting camera, a test search earlier this month demonstrated the difficulty of distinguishing a lander even if the location is known. There have been three successful Mars lander missions, the Viking 1 and Viking 2 in 1976, and the Pathfinder in 1997.

Scientists trained the orbiting camera on the Pathfinder because the location is easiest to find. Several distinct landmarks in the lander's images help identify the spacecraft's location, like Big Crater, Twin Peaks and North Peak.

To snap the photos, the orbiter had to be pointed off of its normal, straight-down view. NASA shot pictures of the Pathfinder location in 1998, but the January 2000 images have much higher resolution, in part because the orbiter took the snapshots from a lower altitude.

Mars scientists determined that they could identify the landing site of the Pathfinder, but could not see the spacecraft or its parachute. Like the lander, the Pathfinder would not be much larger than two pixels in the most resolute images.

The search will continue for a few weeks at most, but the prospects remain poor. "This analysis suggests that it is not very likely that the December 1999 Polar Lander will be found," the Web site for the Mars Orbiter Camera concluded.