This image shows the area within Isidis Planitia where Beagle 2 is intended to land. The orange oval indicates the target landing zone, which is 174 km (108 miles) long.
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The European Space Agency (ESA) launched a mission to Mars called "Mars Express" in June of 2003. The Mars Express spacecraft has two parts: an orbiter that will circle Mars for at least one Martian year (687 Earth days), and a lander named "Beagle 2" which touched down on the surface of the Red Planet on December 25, 2003.
Beagle 2 landed at a site named "Isidis Planitia" just north of the Martian equator. Isidis Planitia is a flat plain within an ancient impact crater that may once have contained a lake or bay. The crater was probably formed by the impact of a comet or 50 km (31 mile) diameter asteroid onto the surface of Mars three to four billion years ago. Isidis Planitia is a relatively low area jutting into the highlands that cover most of Mars' southern hemisphere. It is connected to the low plains that dominate the northern half of Mars. If Mars ever had large oceans they would have covered the northern plains and Isidis Planitia might have been a bay along the edge of that great sea.
The main chore of the Beagle 2 is to search for signs of life. Places that were once covered with water are good candidates for a search for life. The landing site was also chosen for its low altitude. Parachutes work best in relatively thick air, but the atmosphere of Mars is very thin. Since the air is densest at low elevations, lower landing sites give parachutes more of a chance to work. The landing site is also just north of the equator, so it will be springtime on that part of Mars when Beagle 2 lands. The nights won't be quite as cold there as during the winter, which will put less of a strain on the sensitive electronics in the lander. As the mission progresses, spring will give way to summer, so the temperature will be warmer still and there will be longer days during which the lander's solar panels can collect sunlight.
