for National Geographic News
Scientists are clinging to hope that Europe's first probe to land on Mars will speak up and be heard, though no signal from Beagle 2 has been received since it touched down on the red planet Christmas Day.
The British-built probe was jettisoned from its mother ship, Mars Express, on December 19. Upon landing on the red planet December 25, Beagle 2 was to relay a signal of its success via NASA's orbiting Mars Odyssey spacecraft.
However, repeated attempts to hear the Beagle 2's call with Mars Odyssey and an array of powerful radio telescopes on Earth have failed, including the latest try earlier today.
Despite the spacecraft's disappointing silence, Collin Pillinger, lead scientist for Beagle 2, told reporters Saturday in London that he remains optimistic the probe's call will be picked up by Mars Express when it enters a polar orbit on January 4.
"Mars Express is our primary route of communication. It's been the one we spent most of our time over the last four years testing," he said.
At present, Mars Express is in a high orbit around the red planet's equator. On Tuesday, mission controllers will fire its engines to gradually place it in a polar orbit as low as 125 to 155 miles (200 to 250 kilometers) above the Martian surface.
The orbit around one of Mars' poles will allow the spacecraft to survey the entire planet with a high-resolution camera and radar that can look for underground water. It will also be in position to communicate with Beagle 2.
In the meantime, scientists will continue to listen for the as yet unheard from probe with Mars Odyssey and radio telescopes at Jodrell Bank Observatory in Cheshire, England, Stanford University in Palo Alto, California, and possibly other locations, including the Parkes telescope in Sydney, Australia.
Scanning for Signals
The 73 pound (33 kilogram), pocket-watch shaped Beagle 2 was scheduled to land in a 19-mile by 3-mile (30-kilometer by 5-kilometer) lowland basin called Isidis Planitia on December 25 on a mission to search for signs of past or present life.
The pocket-watch design of the probe meant that it would rest upright irrespective of how it landed on Mars. Soon after landing it was to open up and begin sending transmissions to Mars Odyssey.
The orbiting spacecraft did not hear the lander on its first pass over the landing site nor has it on any subsequent pass.
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