Britain’s attempt to send a space mission to Mars next year passed a major milestone yesterday when scientists successfully tested the parachute that will allow the craft, Beagle 2, to land safely on the Red Planet. The white nylon canopy, said to be the most efficient created, was attached to a metal weight and hurled from a balloon 350 ft above a Shropshire airfield. Fluttering in the dawn sunshine, it floated slowly to the ground.