Falling Leaves was the improvised ballistic missile early warning system during the 1962 Cuban Missile Crisis that networked 3 existing CONUS 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 1,500 mi (2,400 km) range, allowing detection in space near Cuba. The "Cuban Missile Early Warning System (CMEWS)" radars were "realigned" to monitor for nuclear missile launches from the new Soviet launch sites after Soviet R-12 Dvina IRBMs arrived on September 8, intelligence sources in Cuba had reported lengthy missiles transported through towns, and three R-12 sites were photographed by Lockheed U-2s by October 19.
Designated by the 9th Aerospace Defense Division at Colorado's Ent AFB, Falling Leaves used the following:
Operations
Falling Leaves operations involved the closest radar in Alabama (newly deployed in 1962) sweeping at a lower ballistic missile altitude from Cuba first. "Then a beam from [the farther] Texas radar swept across the top of [the Alabama beam's altitude]. Finally, a radar in New Jersey was adjusted to sweep over the Texas beam." A "Full Bird Colonel" of Task Force Able watched each "sweep go round and round … each of them had a headset, and an open mike [sic] to NORAD." 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 Titan II ICBM launch 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.
"In the wake [sic] of the Cuban Missile Crisis, an AN/FPS-85 long-range phased-array radar was constructed at Eglin AFB", Florida, beginning in October 1962 (a contract to Bendix Corporation had been issued on April 2, 1962.) In 1972, 20% of the FPS-85 "surveillance capability…became dedicated to search for SLBMs.