Scientists Plan Further Effort to Contact Mars Polar Lander

The latest attempt to detect a signal from NASA’s Mars Polar Lander has so far been inconclusive, but astronomers using radio telescopes around the world will make another try this week, engineers said Monday.

The most recent analysis, performed over the weekend at observatories in California, England and the Netherlands, failed to find any flicker of life from the $165-million probe, which went silent as it was beginning its descent Dec. 3.

The effort was launched after Stanford University engineers thought they might have detected a faint signal at the lander’s radio frequency while reviewing recorded data from earlier attempts to contact the spacecraft.

Last week, NASA beamed commands toward Mars ordering the lander to return a signal. Radio antennas at Jodrell Bank near Manchester, England, and Westerbork in the Netherlands listened--as did the 150-foot dish at Stanford.

“They have been working around the clock to help us and we are grateful for their efforts,” said Richard Cook, the lander’s project manager at NASA’s Jet Propulsion Laboratory in Pasadena.

The space agency’s own antennas will order the lander to respond. A batch of commands ordering the lander to transmit will be sent twice for 30 minutes, with a two-hour cooling down period in between. An additional antenna near Bologna, Italy, also will be listening for a response.

No results are expected until the end of the week at the earliest, given the intensive analysis required to find a signal, Cook said.

Mission controllers are making another attempt because the lander could be in a different configuration than expected and unable to receive or execute the orders sent last week or during a previous attempt involving only the Stanford dish, he said.

The Mars Polar Lander was supposed to contact Earth directly on Dec. 3. It also was equipped to communicate via the orbiting Mars Global Surveyor satellite, which was to have beamed the data back to Earth.

Mission controllers believe the mystery signal detected by Stanford could have originated from the lander if, for some unknown reason, the direct-to-Earth transmitter failed and the Global Surveyor relay also did not work. The antennas in Europe and North America are trying to pick up the signal intended for the orbiter.