When Pathfinder lands on Mars on Independence Day, the images it sends back to Earth will be interpreted with the help of a Cornell University scientist. "We're looking for anything out of the ordinary, in addition to basic geological information," said James Bell, research associate in the Cornell astronomy department's Center for Radiophysics and Space Research.

Bell, chosen for the lander imaging team just a few months ago, will help determine what types of minerals and rocks are present on the Martian surface. The camera, a CCD video camera similar to that used by consumers for home use, is outfitted with about a dozen color filters to discriminate individual minerals. Iron oxide, for example, should be abundant because oxidation of rock is what gives Mars its red color.

"This is really a geology mission," said Bell, who will help with mineralogy and image interpretation. "We'll look at the shape, size and color of the rocks, as well as at geologic formations and surface-atmosphere interactions. We'll be looking for whether the climate was different in the past, too, and anything else that looks interesting."

If successful, images will be stored by the lander camera system and then will be transmitted to Earth two or three times per day, about every eight hours or so.

At night, scientists will use the camera as a telescope, training it on stars and the Martian moons as they pass overhead. "It will be like we're astronomers on the surface of Mars," Bell said.

The camera, called the Imager for Mars Pathfinder (IMP), will make observations at various times during the day to detect any changes over the lifetime of the mission that might be attributed to the actions of frost, dust or sand deposition, erosion or other surface-atmosphere interactions. Observations of the general landscape, surface slopes and the distribution of rocks will be obtained by panoramic stereo images.

Cornell also has a high-capacity mirror site on the Internet for information and to follow the Pathfinder mission. The site, mars.tc.cornell.edu, can accommodate 4 million hits, or accesses, per day. The site is maintained at the Cornell Theory Center, which houses nationally used supercomputers.

A direct link to images on a JPL mirror site at Cornell is http://mars.tc.cornell.edu/default.html.