WASHINGTON NASA and the National Imagery and Mapping Agency (NIMA) are moving forward on joint studies to search for the lost Mars Polar Lander. The craft has been missing in action since it attempted to soft-land on the Red Planet on Dec. 3, 1999.

The craft was believed to have crashed on Mars, busting itself up across the Martian terrain.

But NIMA photo specialists have been poring over NASA-supplied photos snapped by the Mars Global Surveyor spacecraft, now in orbit about Mars. As a support agency of the Department of Defense, NIMA has long been associated with interpretation of high-resolution imagery snapped by Earth-circling military spy satellites.

NIMA ... thought they saw things that indicated the lander, the aeroshell, and the heat shield. We"ve looked at their work and ... we think that what they"ve seen could very well be "noise" in the camera.

In scanning over the Mars Global Surveyor images, NIMA experts believe that the Mars Polar Lander, as well as its protective heat shield and aeroshell, can be seen.

When NIMA presented their data to NASA, however, space agency officials contended that "noise" in the imagery may be contributing to a false interpretation.

"NIMA researchers looked at the images that we provided them early last year. They thought they saw things that indicated the lander, the aeroshell and the heat shield. Weve looked at their work and weve looked at the images. We think that what theyve seen could very well be noise in the camera," Carl Pilcher, NASAs science director for solar system exploration, told SPACE.com.

That noise, or degradation of the image, may be leading to a false interpretation that the Mars Polar Lander has been found, Pilcher said.

In a release issued jointly by NASA and NIMA on March 26, the analysis of Mars imagery has proven "extremely challenging, and has thus far produced no definitive conclusions."

The statement said that NIMA researchers believe they have spotted the Mars Polar Lander and its aeroshell -- the component that protects the craft during its heated entry through the Martian atmosphere. No evidence for the much larger parachute is being claimed.

"One of the principal challenges in locating the missing lander using images from the [Mars Global Surveyor] orbiter is that the Mars Polar Lander is only somewhat larger -- about 6 and a half feet (2 meters) across -- than the smallest objects the orbiter's camera can see on the surface of Mars," the statement said.

In a source familiar with the images being studied by NIMA, several pictures taken of the same area on Mars fail to show the same picture-to-picture pattern of markings believed by NIMA interpreters to be the lander and the other components. That has led to the belief that the features may be electronic noise within the Mars Global Surveyor's camera system.

Presently, the south polar region where Mars Polar Lander was to touch down is in darkness. Twilight begins next month, with full sunlight pouring into the area several months later. When solar elevation angles are high enough -- where shadows may help photo interpreters -- the Mars Global Surveyor is to be tasked to snap more pictures.

"When the site is illuminated once again, more photos will be taken," Pilcher said, and provided to NIMA. "Were going down the pathway together on this," he said.