Linux set for Mars landing

The control centre is ready and a big Christmas celebration is expected when, or if, the UK's most ambitious scientific project, the Beagle 2 Mars Lander, makes landfall on Christmas Day.

In true British low-budget fashion, a single Linux-based workstation at the Lander Operations Control Centre (LOCC) is being used to send commands and receive vital data from Beagle 2.

The diminutive LOCC, part of the new National Space Centre in Leicester, is now fully operational. It has already sent the commands that will be triggered at various times during Beagle 2's descent.

The workstation uses Spacecraft Control Operating System (SCOS) command and control software which sits on top of Linux. Two more Linux-based systems are available as back-up.

Martin Townend, ground system manager with SciSys, the UK company which developed the onboard Lander software, told vnunet.com: "Any one of the three workstations hosting SCOS can be used [for Beagle 2 communication].

"But there are various operators, so one workstation may be used for preparation, another for evaluation and scheduling."

In total there are about 10 high-specification PCs on an Ethernet network within the LOCC, most running supporting applications such as image processing.

Some of these, including a central database, use open source to keep costs low, said Townend.

Data collected will be sent via the internet to the Lander Operations Planning Centre in the Open University at Milton Keynes, or to various other establishments in the UK and Germany, for analysis.

Starting on Friday 19 December will be a period of purgatory for everyone involved, when Beagle 2 is scheduled to separate from the European Space Agency's Mars Express rocket. There is a lot that could go wrong.

Such is the importance of the mission, nobody would comment on a rumour that the Queen was preparing two versions of her Christmas message according to whether or not the Beagle 2 lands successfully.

Professor Alan Wells, programme director for the University of Leicester's Beagle 2 operations, said a rough statistical estimate of success was only 50:50. Past missions have achieved less than 50 per cent success.

"Everything has been tested but there are unknowns. [For instance] we could be unlucky with the landing site, although it was carefully chosen, so we can't communicate easily," he said.

During its descent to the surface of the Red Planet there will be no communication with Beagle 2 while it opens a small parachute, then a larger one, lands on inflated air bags and removes its heat shield.

Mars Express has also to alter its trajectory away from Beagle 2 and into Mars orbit, to send back data of its own. Among UK-developed elements is its propulsion system.

The British National Space Centre, opened three years ago, houses many astronomy exhibits as well as the LOCC. Uniquely, visitors are able view the LOCC at work, including a ground test model of the Beagle 2, through a window.

www.spacecentre.co.uk
www.beagle2.com

A timeline of events is as follows:

17 December
Beagle 2's onboard timer starts the countdown; its power is turned off.

19 December
c8:30am: Beagle 2 is ejected from Mars Express.

25 December
c2.51am UK time: Beagle 2 should make landfall;
5:30am: Nasa's Odyssey satellite will send a signal to see if communication working and send back the first picture;
c11:00pm: Jodrell Bank to send signal communication confirming Beagle 2's survival of its first Martian night.

26 December
Everyone will hear if the Beagle has landed successfully.