Mission controllers were preparing Tuesday for a crucial maneuver to redirect Europe’s Mars orbiter nearer to the Red Planet’s poles the first step in pushing it into a lower orbit where it can listen for its missing Beagle 2 surface probe. The British-built Beagle 2 is believed to have reached the Martian surface early on Christmas Day, its impact softened by gas bags and parachutes. But several attempts to hear its signal have not been successful.