Nation IN BRIEF : FLORIDA : Shuttle Countdown Gets Under Way

NASA began the countdown for the first launch of the shuttle Endeavour and its satellite-rescue mission with spacewalking astronauts. The countdown clocks began ticking at 8 p.m. PDT Monday, and the liftoff is scheduled for 4:06 p.m. PDT Thursday. The seven crew members arrived at the Kennedy Space Center, Fla., Monday night. Endeavour replaces the Challenger, destroyed 73 seconds after liftoff six years ago. All seven crew members died in the fireball. Endeavour’s crew will try to save a communications satellite stranded in a uselessly low orbit for two years. Two astronauts will attach a rocket motor to the satellite that is designed to boost the craft to a working altitude. Other spacewalks are planned so astronauts can practice techniques for building a space station.