The space shuttle Discovery's three 12-million horsepower engines roar to life during a 22-second test at Cape Canaveral, Fla. The crucial firing checked modifications to the engines and other systems with ground-shaking fury and a V-shaped steam cloud. NASA officials pronounced the test a success and have renewed hope for a late September launch date. A firm date will not be set until the test data is analyzed and a small gas leak is repaired.