Falling Leaves (radar network)

Falling Leaves was an improvised ballistic missile early warning system of the United States Air Force. It was set up during the 1962 Cuban Missile Crisis, and networked 3 existing U.S. radars—2 Space Detection and Tracking System (SPADATS) radars and an Aircraft Control and Warning general surveillance radar which was modified by Sperry Corporation to 1500 mi range, allowing detection in space near Cuba. The designation was assigned by the 9th Aerospace Defense Division, headquartered at Ent AFB, Colorado.

Soviet R-12 Dvina IRBMs arrived in Cuba on September 8. Intelligence sources in Cuba then reported lengthy missiles transported through towns, and three R-12 sites were photographed by Lockheed U-2s by October 19. Afterwards, the "Cuban Missile Early Warning System (CMEWS)" radars were "realigned" to monitor for nuclear missile launches from the new Soviet launch sites.

The Falling Leaves system used the following:
 * RCA AN/FPS-49 Radar Set prototype of 1961 in New Jersey during development for the under-construction BMEWS Site III which was to have 3 of the tracking radars. The prototype was "withdrawn from SPADATS and realigned to provide missile surveillance over Cuba" on 24 October.
 * AN/FPS-78 in Texas, to which was added "real time radar display equipment" from an Alaska radar station. (realigned 26 October)
 * Sperry AN/FPS-35 Frequency Diversity Radar in Alabama, operated by "Task Force Able" and later awarded a Unit Citation for Falling Leaves (698th commanded by Lt. Colonel Kenneth Gordon). (30 October)

Operations
As Fred Dobbs writes of his experience as an airman at Thomasville Air Force Radar Base in Alabama (newly deployed in 1962),

"In early October, 1962, we received word that a special team from Sperry was coming in to extend the range of our receiver by three to five times. This would make it possible for us to see objects up to 1500 miles away. At that range, our beam would be in space due the [sic] curvature of the earth. ... Our beam [from Alabama] was sweeping over Cuba first. Then a beam from a Texas radar swept across the top of ours. Finally, a radar in New Jersey was adjusted to sweep over the Texas beam. ... Now every scope had a 'Full Bird Colonel' watching the sweep go round and round. ... Each of them had a headset, and an open mike to NORAD. If they saw a missile lift off from Cuba the word would be given to launch ours."

Information communicated to the Ent AFB BMEWS Central Computer and Display Facility was synthesized to provide missile warning to display processors at the Pentagon and Strategic Air Command.

The FPS-49 radar detected a Cape Canaveral launch Titan II ICBM on October 26 (N-12 Mk 6 reentry vehicle test) —the trajectory was determined to be safely Southeastward over the Atlantic Missile Range. On October 28, a test tape inserted at the New Jersey radar site caused a false alarm indicating a missile would impact Tampa and later the same day, an unidentified radar track over Georgia was recognized as a satellite. On November 28 the New Jersey and Texas radars returned to their SPADATS mission, and the Alabama radar continued coverage for Cuba launches until late December.

After the Cuban Missile Crisis, a contract to Bendix Corporation was issued on April 2, 1962 to construct a long range radar at Eglin AFB, FL. Thus a AN/FPS-85 long-range phased-array radar was constructed beginning in October 1962.

In 1972, 20% of the FPS-85 "surveillance capability…became dedicated to search for SLBMs.