DOD: The LGM 30B Minuteman I missile was on strategic alert at Launch Facility (LF) L-02, Ellsworth Air Force Base, South Dakota. Two airmen were dispatched to the LF to repair the inner zone (IZ) security system. In the midst of their checkout of the IZ system, one retrorocket in the spacer below the Reentry Vehicle (RV) fired, causing the RV to fall about 75 feet to the floor of the silo. When the RV struck the bottom of the silo, the arming and fusing/altitude control subsystem containing the batteries was torn loose, thus removing all sources of power from the RV. The RV structure received considerable damage. All safety devices operated properly in that they did not sense the proper sequence of events to allow arming the warhead. There was no detonation or radioactive contamination. >
CDI: The Minuteman I was a three stage intercontinental ballistic missile carrying a one megaton warhead. The first missiles became operational in November 1962. Throughout the 1960s and 1970s they were gradually replaced by Minutemen IIs and Ills. The Office of Technology Assessment study calculated that a one megaton surface burst in Detroit would cause 70 square miles of property destruction, a quarter of a million fatalities, and half a million injuries.