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Scientists Wait For Beagle 2 To Call Home

Status Report From: Particle Physics and Astronomy Research Council
Posted: Friday, December 26, 2003

image The fate of Beagle 2 remains uncertain this morning after the giant radio telescope at Jodrell Bank in Cheshire, UK, failed in its first attempt to detect any signal from the spacecraft.

Scientists were hopeful that the 250 ft (76 m) Lovell Telescope, recently fitted with a highly sensitive receiver, would be able to pick up the outgoing call from the Mars lander between 19.00 GMT and midnight last night. An attempt to listen out for Beagle's call home by the Westerbork telescope array in the Netherlands was unfortunately interrupted by strong radio interference.

The next window of opportunity to communicate via Mars Odyssey will open at 17.53 GMT and close at 18.33 GMT this evening, when the orbiter is within range of the targeted landing site on Isidis Planitia.

Another communication session from Jodrell Bank is scheduled between 18.15 GMT and midnight tonight, when Mars will be visible to the radio telescope. It is also hoped that the Stanford University radio telescope in California will be able to listen for the carrier signal on 27 December.

The Beagle 2 team plans to continue using the Mars Odyssey spacecraft as a Beagle 2 communications relay for the next 10 days, after which the European Space Agency's Mars Express orbiter will become available.

Mars Express, which was always planned to be Beagle 2's main communication link with Earth, successfully entered orbit around the planet on 25 December and is currently being manoeuvred into its operational polar orbit.

Meanwhile, 13 more attempts to contact Mars Odyssey have been programmed into Beagle 2's computer. If there is still no contact established after that period, Beagle 2 is programmed to move into auto-transmission mode, when it will send a continuous on-off pulse signal throughout the Martian daylight hours.

The first window of opportunity to communicate with Beagle 2 took place at around 06.00 GMT yesterday, when NASA's Mars Odyssey spacecraft flew over the planned landing site. In the absence of a signal from the 33 kg lander, the mission team contacted Jodrell Bank to put their contingency plan into operation.

At present, Beagle 2 should be sending a pulsing on-off signal once a minute (10 seconds on, 50 seconds off). Some 9 minutes later, this very slow "Morse Code" broadcast should reach Earth after a journey of some 98 million miles (157 million km).

Although the Beagle's transmitter power is only 5 watts, little more than that of a mobile phone, scientists are confident that the signal can be detected by the state-of-the-art receiver recently installed on the Lovell Telescope. However, a significant drop in signal strength would require rigorous analysis of the data before it could be unambiguously identified.

Although the ground-based radio telescopes will not be able to send any reply, the new information provided by detection of the transmission from Beagle 2 would enable the mission team to determine a provisional location for Beagle 2. This, in turn, would allow the communications antenna on Mars Odyssey to be directed more accurately towards Beagle 2 during the orbiter's subsequent overhead passes.

NOTES FOR EDITORS

Beagle 2 transmits at a frequency of 401.56 Mhz.

There are a number of possible explanations for Beagle's failure to call home. Perhaps the most likely is that Beagle 2 landed off course, in an area where communication with Mars Odyssey was difficult, if not impossible. Another possibility is that the transmission from the lander's antenna is blocked from reaching Mars Odyssey or the ground-based telescopes.

Beagle 2 was targeted to land in a large lowland basin called Isidis Planitia at 02.54 GMT on 25 December. The "pocket watch" design of Beagle 2 ensured that it would turn upright irrespective of which way up the little lander fell. Soon after, the onboard computer was expected to send commands to release the clamp band, open the lid and begin transmission.

The next vital stage was to deploy the four, petal-like solar panels and initiate charging of the batteries. When the Sun set below the Martian horizon a few hours later, the lander was scheduled to go into hibernation so that it could survive the subzero night-time temperatures.

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