NASA managers Wednesday cleared the shuttle Discovery for blastoff Monday on the year's first shuttle flight, an oft-delayed mission to carry a $100 million satellite into orbit. The launch date, Discovery's second in less than one week, was announced after engineers completed replacing and testing a critical computer part that failed earlier this week. Under the new schedule, Discovery's countdown will begin at 10:01 p.m. MST Thursday, leading to a launch attempt Monday at 6:07 a.m. MST. The ship's crew - commander Michael Coats, 43, co-pilot John Blaha, 46, James Bagian, 37, Robert Springer, 46 and James Buchli, 43 - will fly to the Kennedy Space Center Friday.