Scientists Wait For Beagle 2 To Call Home

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.