The AN/FPS-120 is a solid state, phased-array radar developed by Raytheon. Computers are used to control the radar and process the data it receives. Vital communications are also maintained through a number of systems. The AN/FPS-120 detects objects as far out as 2,800 nautical miles and can look over a 240-degree sweep, also being able to detect, at an extreme range, objects the size of a small car. Also called the SSPAR, the newly completed AN/FPS-120 was activated on February 1, 2001, after the deactivation of the Clear Air Station's mechanical BMEWS radar. Since then, performance of the upgraded AN/FPS-120 system has been exceptional, with over 99-percent availability, a substantial factor in the cost reduction.
The AN/FPS-120 radar is housed in a triangular-shaped 11 story building on site. The steel frame building that houses two approximately 90' diameter radar array faces on exterior walls and all related equipment. Together they form a coverage area 240 degrees wide and 3,000 miles deep into space. The coverage extends from the Arctic Ocean all the way to the West Coast of the lower 48 states. The upgrade program implemented by Raytheon has enhanced the performance of all three systems, while significantly reducing their operation and maintenance costs.