On March 16, 1962, the United States conducted its first test of the Titan II ICBM, a two-stage liquid-fueled rocket capable of being launched from a hardened silo (unlike its predecessors, the Atlas and Titan I ICBMs). By the end of 1963, a total of 56 Titan II ICBMs had been deployed. (The number would eventually reach 60 in 1966 before dropping to 54--18 in Arkansas, 18 in Arizona, and 18 in Kansas--in 1967.) In addition to carrying the largest nuclear payloads, the Titan II was also used as the launch vehicle for NASA's Gemini manned space program and for many of the U.S. Air Force's largest satellites.
Almost as soon as it was deployed, however, the Titan II was made obsolete by the Minuteman solid-fuel ICBMs. Solid-fuel missiles were more reliable, easier to maintain, and capable of being launched more quickly (thus the name "Minuteman"). By the end of 1967, there were 1,000 Minuteman ICBMs deployed in Wyoming, Montana, North Dakota, South Dakota, and Missouri.
One of the reasons the Titan II ICBMS were kept around for two decades after the completion of the Minuteman deployment was ability of the Titans to carry large payloads. The largest warhead ever deployed by the United States--a nine megaton thermonuclear device--was placed atop a Titan II. (According to one of the displays at the Titan Missile Museum, a warhead that size would have the destructive power of a train with 90,000 boxcars--long enough to stretch 1,534 miles--filled with TNT.)
The Reagan Administration's Strategic Forces Modernization Plan, drafted in 1981, called for the elimination of the Titan II ICBMs by the end of 1987. The 54 Titan IIs were removed from their silos and in every case the silos were destroyed--except for the silo near Sahuarita, Arizona just south of Tucson.
Through the intervention of the Pima Air Museum, Site 571-7 was preserved as a museum. A Titan II test rocket was disabled, placed in the silo, and the silo door was permanently fixed in a half-open position (to assure the Soviets/Russians, via their satellite reconnaissance, that the silo was not operational). The satellite photo here shows the silo in the half-open position.
Today, volunteers at the Titan Missile Museum take visitors on an hour-long tour through the surface facilities, down into the silo, and into the underground control room. It is, as the museum likes to note, a step back in time to the front lines of the Cold War.
And that's what I did with my free time while in Tucson last week for the ISSS/ISAC Conference.