PASADENA, Calif. - The effort to hear from the Mars Polar Lander has gone global.
On Friday NASA announced it has asked the Dutch, English and Italians for help in determining whether recently detected radio signals could have come from the errant spacecraft.
A spokeswoman at NASAs Jet Propulsion Laboratory (JPL) said the American space agency has contacted various international radio observatories to listen for feeble signals from the Polar Lander.
"We want to get to the bottom of whether this was a bona fide signal," said JPL spokeswoman Mary Hardin of the international appeal.
Although NASA announced on January 17 the spacecraft was likely dead, Stanford engineers reported on Monday that they may have detected a signal that could have from the landers UHF transmitter on December 18 and January 4. The lander has been silent since it began its descent through the martian atmosphere on December 3.
Engineers failed to notice the signals -- which very well could be from terrestrial sources -- in real time, uncovering them only in subsequent processing of the data received by the universitys 150-foot (45-meter) antenna in Palo Alto, California.
The Netherlands Foundation for Research in Astronomy (NFRA) announced Friday it would assist in the search, pressing into service the 14 radio antennas -- each 83 feet (25 meters) across -- at its
Synthesis Radio Telescope facility.The array will begin scanning the skies for a signal from the $165 million Mars spacecraft at the end of next week. NASA has also made appeals to Jodrell Bank Observatory in England and an observatory near Bologna, Italy, but has not yet received a reply, Hardin said.
Engineers sent further commands to the spacecraft this week, telling to it to answer via its UHF transmitter, and listened on Wednesday and Thursday for a return message. Stanford engineers do not expect to finish processing that data until next week, at which time they expect to learn if a reply was sent.
And even more commands will be sent in the middle of next week, Hardin said.
The Dutch array would be poised to listen for any answer from the Polar Lander at that time.
If the spacecraft is intact and sending signals from its UHF transmitter, they would be extremely weak --- about one watt, or the equivalent of a Christmas tree light on Mars -- said Polar Lander project manager Richard Cook. NASA engineers designed the UHF receiver for use in communicating with an orbiting relay craft, such as the orbiting Mars Global Surveyor, not directly to Earth.
However, the Dutch array is the most sensitive in the world in the particular radio frequency the Polar Lander could be using. Dutch astronomers normally use the array, nearly 2 miles (3 kilometers) long, to study far weaker natural radiation from distant galaxies and stars.
To ready the array, Dutch astronomers have spent the last few days inventorying all of the Earthly signals that could interfere with the search, according to a press release from the NFRA.
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