Similar incidents happened many times in the United States , due to failed computer chips , misidentifications of large flights of geese , test programs , and bureaucratic failures to notify early warning military personnel of legitimate launches of test or weather missiles . For many years , the U.S. Air Force 's strategic bombers were kept airborne on a daily rotating basis " around the clock " ( see Operation Chrome Dome ) , until the number and severity of accidents , the 1968 Thule Air Base B-52 crash in particular , persuaded policymakers it was not worthwhile
1968 Thule Air Base B-52 crash
1968 Thule Air Base B-52 crash
Nuclear warfare