An image taken by Mars Global Surveyor in the search for visible evidence of the missing Mars Polar Lander. Box is just under 1,000 meters across. Learn more about the image. Photo: NASA/JPL/MSSS

Flight controllers for Mars Polar Lander are continuing to work through their fault-tree scenarios in their ongoing attempts to communicate with the spacecraft. Chances of recovering the lander remain remote.

Team members plan to continue looking for a signal from the lander through mid-January, and at that point they will be in a position of having exhausted all possible recovery modes.

Late last week, NASA's orbiting Mars Global Surveyor spacecraft began an imaging campaign to look for evidence of the lander, parachute or aeroshell. So far, nothing has been detected.

The effort started on Thursday, December 16 using MGS' high resolution Mars Orbiter Camera (MOC) operated by Malin Space Science Systems of San Diego, California.

Mars Polar Lander was lost during its landing attempt near 76.3 degrees South, 195.0 degrees West on the Martian south polar layered terrain on December 3. Although the likelihood of seeing the lander is quite small, the MOC effort might provide some clues that shed light on what happened to the lander. The problem, however, is one of "pixels" -- those little square boxes of different shades of gray that comprise a digital image.

How is the MGS MOC team looking for the lander?

Primarily, they are looking for associations of features that, together, would suggest whether or not the Mars landing was successful. For example, the parachute that was used to slow the lander from supersonic speeds to just under 300 km/hr (187 mph) was to have been jettisoned, along with part of the aeroshell that protected the lander from the extreme heat of entry, about 40 seconds before landing. The parachute and aeroshell are likely to be within a kilometer (6-tenths of a mile) of the lander. The parachute and aeroshell are nearly white, so they should stand out well against the red martian soil. The parachute, if lying on the ground in a fully open, flat position, would measure about 6 meters (20 feet) -- thus it would cover three or four pixels (at most) in a MOC image. If the parachute can be found, the search for the lander can be narrowed to a small, nearby zone.

If, as another example, the landing rockets kicked up a lot of dust and roughened the surface around the lander, evidence for this might show up as a dark circle surrounding a bright pixel (part of the lander) in the middle. The MOC operations team is using a set of these and similar scenarios to guide the examination of these images. The search continues.

The Jet Propulsion Laboratory has appointed a special review board to evaluate the apparent loss of Mars Polar Lander and the Deep Space 2 microprobes. The board will attempt to determine the possible root causes for these losses and identify actions needed to assure success in future Mars landings.

The 12-member JPL board will be chaired by John Casani and is made up of members from JPL, Caltech, other NASA centers and industry. The findings of the board will be presented in a written report due by March 3, 2000. The board will offer its cooperation and assistance to related NASA efforts including the agency's Mars Program Independent Assessment Team.

Mars Polar Lander is part of a series of missions in a long- term program of Mars exploration managed by JPL for NASA's Office of Space Science, Washington, D.C. JPL's industrial partner is Lockheed Martin Astronautics, Denver. JPL is a division of the California Institute of Technology, Pasadena, Calif.