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First of all, to deliver the lander where planned, Mars Express has been put on a collision course with Mars, since Beagle 2 does not have a propulsion system of its own and must therefore be 'carried' precisely to its destination. This means that after separation, Mars Express has to veer away quickly to avoid crashing onto the planet. The landing site for the European rover called Beagle 2 lies on the floor of a large impact basin in the northern hemisphere of Mars. The name of the site, Isidis Planitia, refers to the broad, relatively flat plain that covers the floor of an extremely ancient, large basin formed by an asteroid or comet impact perhaps more than 4 billion years ago. During the cruise Beagle 2 will take its power from the mother spacecraft, Mars Express. After separation and until its solar arrays are fully deployed on the surface, Beagle 2 must rely on its own battery, which cannot last beyond 6 days. So, like a caring parent, Mars Express must release Beagle 2 at the last possible moment to ensure that the lander has enough power for the rest of its journey to the surface. Only then can Mars Express change its orientation and rapidly fire the thrusters to get away from the collision course and enter into orbit around Mars. This will be the first time that an orbiter delivers a lander without its own propulsion onto a planet and attempts orbit insertion immediately afterwards. Since all these maneuvers are time-critical and allow little margin of error, the ground control team has had to simulate all possible scenarios (including glitches and problems, on board and on the ground) to make sure that nothing is left to chance. The team has been training since September in a very realistic setting, using the same computers and equipment that will be employed during this mission phase. Although the real spacecraft cannot be directly involved, its behaviour is simulated via a sophisticated computer programme, using the actual flight software. These rehearsals, each lasting a day or more, cover all possible situations from the failure of an onboard instrument to the outbreak of a fire in the control room. One of these simulations will take place during the press conference on 3 December.
ESA's ground control team at ESOC, on the other hand, are having a very busy time. They are actively rehearsing responses to any situation that might arise when Mars Express releases Beagle 2 and enters into orbit around Mars. "The Mars Express mission is pushing the operations staff to extremes. Over the years, the experience acquired with experimental missions has provided a solid basis on which to prepare for the unexpected. The satellite controllers will rise to this new challenge", Gaele Winters, ESA Director of Technical and Operational Support, said. Employing seven major instruments for its on-the-spot analyses, Mars Express will be able to identify signs of water in liquid, solid, or vapour form on Mars. Its lander will take a good chemical and morphological look at its landing site, looking for water in the soil, on rocks, and in the Martian atmosphere. It will investigate the existence of carbonate minerals and organic residues to detect possible signs of past or present life. Related Web PagesWhere is the Mars Express Now?Where is Spirit Now? Athena Science: Cornell University Mars Image Rendering: space4case.com Nozomi, Planet-B Five Year Retrospective: Mars Pathfinder Note: Mars Life Display Options: Sunday, November 30, 2003 |
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