in Colorado being placed on alert that June. Beginning in November 1959, in order to counter Soviet surface-to-air missile threats, SAC began adding low-altitude bombing training for its manned bomber force as an adjunct to its legacy high-altitude training. Use of low level flight route corridors known as "Oil Burner" routes (later renamed "Olive Branch" routes in the 1970s), and the first of three SAC RBS trains were utilized starting in 1960. On 30 June 1960, SAC had 696 aircraft on alert in the Zone of Interior, also known as the ZI (referred to today as the Continental United States, or CONUS) and at overseas bases. These 696 aircraft were 113 B-52s, 346 B-47s, 85 KC-135s, and 152 KC-97s. SAC's Emergency War Order (EWO) required the first aircraft to be airborne within 8 minutes and all aircraft to be airborne within 15 minutes after notification. During the mid-1950s, having recalled numerous World War II USAAF and Korean War USAF combat veteran pilots, navigators, bombardiers and aircrewmen from inactive reserve status back to various lengths of active duty, SAC took the lead in integrating the Air Force's reserve components into the overall SAC structure. By the beginning of the 1960s, SAC had also engineered the assignment of KC-97 Stratofreighter aerial refueling aircraft to Air National Guard groups and wings and having them fall under SAC's operational claimancy. On 11 August 1960, President Eisenhower approved the creation of the Joint Strategic Target Planning Staff (JSTPS), co-located at SAC headquarters at Offutt AFB.) JSTPS also included non-SAC agencies tasked with preparing the Single Integrated Operation Plan, or SIOP, and the National Strategic Target List for nuclear war. On 1 July 1960, a SAC RB-47 with a six-man crew was shot down in international airspace over the Barents Sea by a Soviet MiG-19. Four of the crewmen were killed and two surviving crewmen were captured and held in Lubyanka Prison in Moscow for seven months. On 3 February 1961, SAC's Boeing EC-135 Looking Glass, began operations as the Airborne Command Post for the Nuclear Triad and the Post-Attack Command and Control System. From this date and for the next years, until 24 July 1990, SAC would maintain at least one Looking Glass aircraft continuously aloft 24 hours a day, 365 days a year, with an embarked SAC general officer and battle staff, ready to assume command of all strategic nuclear strike forces in the