Historic California Posts, Camps, Stations and Airfields
Travis Defense Area Site T-53 (Potero Hills)
(Potero Hills Storage Annex)
by Daniel M. Sebby

The property required for former Travis Defense Area Site T-53 was acquired in 1956 by purchase and condemnation proceedings against several private landowners. When the acquisitions were competed, the U.S. Army Corps of Engineers (USACE) had acquired 56.46 acres by fee and 280.59 acres through 27 easements.

The U.S. Army's Cold War antiaircraft/air defense artillery sites were identified by an identification system that included the initial(s) of the defense area and a site number (i.e. T-53 meaning Travis AFB Defense Area Site 53). A suffix was added to the initials of the Site identifying the function of the site (or portions of the site) that would have included suffixes for gun and missile batteries (L), command and control facilities (C), and administrative and family housing areas (A).

Administrative Area (T-53A): The administrative area contained the Site's administrative and support functions. Administrative and support functions included troop housing and messing, recreational facilities, battery administration and supply buildings, and vehicle maintenance facilities.

Control Area (T-53C): The control area (also known as the Integrated Fire Control or "IFC" area) was the location of the battery's radar and fire control systems. The IFC area was located adjacent to the administrative area and allowed for 360 degree "line of site" radar coverage by the battery's missile and target tracking and search radar systems. The missile tracking radar would "lock on" to the missiles while they sat on the launcher and follow them from launch to impact with the target. The reason for locating the IFC site away from the launch area was because the high speed of the Nike family of missiles would have destroyed the tracking mechanisms of the missile tracking radar if they were located too close to the launchers.

Launch Area (T-53L): The launch area was located to the southeast of the Administrative Area and consisted of 12 launchers and 3 magazines (underground storage "bunkers") that held a total of 30 MIM-3 Nike-Ajax multi-stage surface-to-air missiles. Additionally, the launcher area also housed missile and warhead assembly, maintenance, and fueling facilities. The launch area was the most secure area of the Site and included a ready room for missile crews when the battery was in a "hot" or ready status, security checkpoints, and a kennel for military working dogs

The Site was initially garrisoned in January 1957 by Battery B, 436th Antiaircraft Artillery Missile Battalion, U.S. Army (one of the oldest units of the U.S. Army, tracing its lineage to Captain Nathan Eastbrook's Company of Light Artillery organized in 1803). In September 1958, the U.S. Army reorganized the field and antiaircraft artillery branches under the Combat Arms Regimental System (CARS) and the 436th Antiaircraft Artillery Missile Battalion, U.S. Army was reorganized as the 1st Missile Battalion, 61st Artillery Regiment, U.S. Army.

In 1958, the Travis AFB Defense Area began converting two of its batteries (Battery A at Elmira [T-10] and Battery C at Fairfield/Cement Hills [T-86]) to the newer, nuclear capable MIM-14 Nike-Hercules missiles. Battery B and Battery D at Dixon/Lambie (T-33) retained their Nike-Ajax missiles until January and September 1959 (respectively) when they were inactivated.

In 1964, a portion of the Launcher Area was transferred from the U.S. Army to the U.S. Air Force and was redesignated as Potrero Hills Storage Annex, a sub-installation of nearby Travis AFB. The U.S. Air Force still controls this area (which is currently leased to a defense contractor).


The Western Electric SAM-A-7/M1/MIM-3 Nike Ajax

The Nike Ajax was the world's first operational surface-to-air guided missile system. Its origins lay in the immediate post-war time, when the U.S. Army realized that guided missiles were the only way to provide air-defense against future fast high-flying bombers. Western Electric became the prime contractor for the XSAM-G-7 Nike missile system and Douglas as the primary subcontractor was responsible for the missile airframe.

The first unguided Nike missiles were fired in 1946, but problems with the original multi-rocket booster (eight solid-fuel rockets wrapped around the missile tail) soon led to delays in the program. In 1948, it was decided to replace this booster pack with a single rocket booster, attached to the back of the missile. The main propulsion of the missile was a Bell liquid-fueled rocket motor, and the flight path was controlled by the four small fins around the nose. In November 1951, the first successful interception of a QB-17 target drone succeeded. The first production Nike (which had been redesignated SAM-A-7 in 1951) flew in 1952, and the first operational Nike site was activated in 1954. By this time, the missile had been designated by the Army as Guided Missile, Anti-Aircraft M1. The name had changed to Nike I, to distinguish it from the Nike-B (later MIM-14 Nike Hercules) and Nike II (later LIM-49 Nike Zeus). On 15 November 1956, the name was finally changed to Nike Ajax.

The Nike Ajax missile used a command guidance system. An acquisition radar called LOPAR (Low-Power Acquisition Radar) picked up potential targets at long range, and the information on hostile targets was then transferred to the Target Tracking Radar (TTR). An adjacent Missile Tracking Radar (MTR) tracked the flight path of the Nike Ajax missile. Using tracking data of the TTR and MTR, a computer calculated the interception trajectory, and sent appropriate course correction commands to the missile. The three high-explosive fragmentation warheads of the missile (in nose, center, and aft section) were detonated by ground command, when the paths of target and missile met.

One of the major disadvantages of the Nike Ajax system was that the guidance system could handle only one target at a time. Additionally, there was originally no data link between different Nike Ajax sites, which could lead to several sites engaging the same target. The latter problem was eventually solved by the introduction of the Martin AN/FSG-1 Missile Master command-and-control system, with automatic data communication and processing. Other problematic features of the Nike Ajax system were the liquid-fuel rocket motor with its highly toxic propellants, and the large size of a complete site with all components, which made Nike Ajax to all intents and purposes a fixed-site air defense system.

By 1958, nearly 200 Nike Ajax sites had been activated in the United States. However, the far more advanced MIM-14 Nike Hercules soon replaced the Nike Ajax, and by late 1963, the last Nike Ajax on U.S. soil had been retired. In 1963, the Nike Ajax had received the new designation MIM-3A. Despite the use of an MIM (Mobile Intercept Missile) designator, the mobility of the Nike Ajax system was more theoretical than actually feasible in a combat situation.

The MIM-3A continued to serve with U.S. overseas and friendly forces for many more years. In total, more than 16,000 missiles were built.


Source: Directory of U.S. Missiles and Rockets, http://www.designation-systems.net/



Search our Site!
Search the Web Search California Military History Online
Questions and comments concerning this site should be directed to the Webmaster
Updated 8 February 2016