Artist's concept of Mars Polar Lander near the Martian south pole. Photo: NASA

Radio scientists at California's Stanford University are continuing to process data from communications attempts made Wednesday and Thursday to determine if they have picked up a signal coming from Mars Polar Lander using their 45-meter (150-foot) antenna.

There were three 30-minute communications windows Wednesday and three more listening windows Thursday. It takes about 18 hours to process the data from each window. So far, Stanford scientists have looked at one of the three data sets taken Wednesday and say they have not detected anything unusual. It will take several days to complete the processing and the researchers do not expect to have confirmation of a signal until some time next week.

"The signal we are looking for is very, very weak, about 1 watt of power -- or like looking for a Christmas tree light on Mars," said Richard Cook, Polar Lander project manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Because of the weakness of the signal, we want to be absolutely sure we have something so we will check and double check these data before we will be willing to confirm there is a signal."

Mars Polar Lander is managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, Washington, D.C. Lockheed Martin Astronautics Inc., Denver, Colo., is the agency's industrial partner for development and operation of the spacecraft. JPL is a division of the California Institute of Technology in Pasadena.