Clear Air Force Station is a United States Air Force Station located 5 miles (8 km) south of Anderson, Alaska, USA, northeast of Mount McKinley, and southwest of Fairbanks. Located at this base is the 13th Space Warning Squadron, a part of the 21st Space Wing, Peterson Air Force Base and NORAD. Its primary mission is to detect incoming ICBMs and submarine-launched ballistic missiles.
The history of Clear as a radar site really began in 1957 with the Soviet launch of Sputnik. The US could no longer ignore the threat of Soviet ICBMs, and the early detection of enemy launches became a national priority. In 1959, a strip of wilderness at Clear was appropriated to become Site II of the Ballistic Missile Early Warning System (BMEWS). Site I, Thule Air Base, was already under construction at Thule, Greenland, and Site III, RAF Fylingdales, would soon follow near Fylingdales Moor, North Yorkshire, England. A humble camp area was erected adjacent to the railroad, and groundbreaking for the new radar took place in May 1959. Over the next two years, construction would continue on the three massive detection radars that would become Clear's trademark. The radars, designed by GE and MIT's Lincoln Lab and built by RCA, measure , and weigh apiece. Considering there were no major roads in the area at the time, the construction of Clear was an enormous undertaking with a final price tag of $360,000,000.
In 1964, the Good Friday Earthquake, the second largest earthquake ever recorded, shook Alaska. Although no casualties were sustained, the earthquake caused the site to "go red" (unable to perform the mission) for six minutes.
Although designed to detect incoming missiles, Clear's radars were also useful in tracking satellites in low-earth orbits. Further improving this capability, as well as providing enhanced accuracy of launch and impact predictions, was the mechanical tracking radar, an diameter radar on a moving pedestal housed in a foot diameter radome. The tracker became operational in 1966.
On January 1, 1967, Det 2 became the newly created 13th Missile Warning Squadron. One of the squadron's first acts was to provide emergency shelter to 216 refugees from Fairbanks and the surrounding area when a devastating flood struck the region in August 1967. That same year, the squadron was given funding for additional building construction. Despite the new construction, many of the "temporary" buildings from the original camp area are still in use today.
Throughout the '60s and early '70s, Clear played a part in a series of experiments affecting its radars. One such experiment was conducted by the University of Alaska, which injected sulfur hexafluoride into the upper atmosphere to see if the Aurora Borealis could be dissipated or intensified.
In 1971, the 13th MWS was reassigned from the 71st Missile Warning Wing to the 14th Aerospace Force. The '70s also saw a number of firsts at Clear, including the assignment of its first female officer in 1973. In the same year, the 13th MWS was awarded its second Air Force Outstanding Unit Award. The 13th was reassigned from Air Defense Command to the Strategic Air Command (SAC) through 15th Air Force in 1979.
The 13th was again reassigned on 1 May 1983, this time to Space Command's 1st Space Wing. Another first at Clear, which received a lot of local publicity, was the first all-female crew, which pulled a shift on 28 February 1986.
When Thule and Fylingdales were converted to phased-array radar systems, Clear became the last mechanical missile warning site in the US. It was decided that Clear would be upgraded with a phased-array as well, and the Clear Radar Upgrade (CRU) was born.
Rather than build a completely new radar, the CRU utilized existing radar components from the deactivated PAVE PAWS SLBM warning site at Eldorado Air Force Station, Texas. Ground was broken for the new radar in April 1998. The new radar is known as the Solid-State Phased-Array Radar System (SSPARS — pronounced "ES-pars"). On 15 December 2000, after nearly 40 years of operation, the last of the original BMEWS radars ceased transmitting, and the SSPARS began 24-hour operations. Initial Operational Capability was declared on 31 January 2001.