IT WILL BE SUNDAY at the earliest before space shuttle Discovery, grounded by an engine problem, will be able to fly, NASA officials say. . . . AN EXPLOSION, apparently resulting from an attack, damaged a NATO fuel pipeline early Wednesday near the northern German city of Hude west of Bremen, police said. . . . KARL KLASEN, whose tight monetary policy as head of Germany's central bank helped make the German mark one the world's most stable currencies, died Monday at age 81 in Hamburg. . . . A DOG weighing more than 100 pounds attacked and killed an 8-year-old boy who climbed over a fence, authorities said. Ishmael Gonzales was pronounced dead in Southwest Medical Center at Liberal, Kan., shortly after Tuesday's attack.