NASA isn鈥檛 giving up yet on the missing Mars Polar Lander. After an initial
effort failed to confirm that the lander was the source of a faint radio beep,
NASA hopes more sensitive antennas might succeed. That might mean a reprieve for
the Mars Surveyor 2001 Lander programme. The agency was expected to cancel the
programme because it relied on the same design as its predecessor.
NASA wrote off the lander on 17 January after weeks of trying to make
contact. But just days later, Stanford University astronomers called to say they
had detected possible signals from the probe on 18 December and 4 January. 鈥淚
was blown away when the phone call came,鈥� says Sam Thurman, the lander鈥檚 flight
operations manager at the Jet Propulsion Laboratory in California.
Mission controllers had spent six weeks trying to coax some response from the
lander, which reached the surface of the Red Planet in early December. As a long
shot, they ordered the lander to switch on its ultra-high-frequency (UHF) band
transmitter and send a test signal into space. But hunting for the signal was
like 鈥渢rying to see somebody on Mars with a penlight鈥�, Thurman said.
Nonetheless, after weeks of searching, Stanford astronomers spotted faint
signals at the right times and frequencies for the lander.
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Because ground and satellite transmitters cause massive interference in the
UHF band, Stanford turned its radio-telescope back towards Mars in the hope of
confirming the authenticity of the signal. Initial tests have failed to do so,
they announced this week. However, they are rechecking their data, and NASA
isn鈥檛 giving up. Dutch astronomers have also joined the effort using their ultra
UHF-sensitive Westerbork Synthesis Radio Telescope. The 76-metre Jodrell Bank
Dish is also being turned towards Mars.
Peter Smith, principal investigator for the polar lander at the University of
Arizona, is optimistic that contact will be made. 鈥淚 saw the actual signature,
the plot of frequency versus time. It was clearly a signal,鈥� he told New
快猫短视频. Despite this, he admits there is 鈥渘o hope of getting science
through Stanford鈥檚 radio telescope鈥�, because the signals are too weak to extract
data.
However, Thurman says his JPL team is looking for ways of persuading the
spacecraft to relay information on its condition by turning its transmitter off
and on. That might tell them whether the probe landed on a slope and couldn鈥檛
point its X-band antenna toward the Earth. If so, NASA will need to modify the
2001 lander accordingly so it can be launched on schedule in April next
year.