Although the Cold War ended in 1991, the U.S. and Canada still maintain a string of radar stations from Alaska to Greenland. The system, originally called the DEW (Distant Early Warning) Line, was built in the 1950s, to detect Russian bombers or reconnaissance aircraft coming in. Right across the Arctic Ocean, and the North Pole from the northern coast of North America, is the north coast of Russia. Right across the pole is the shortest distance (for aircraft or ballistic missiles) from Russia to North America.
After the Cold War ended, Canada took over control of the entire system, which is now managed from an underground facility in Ontario. The U.S. still picks up 60 percent of the cost, and has access to information the radars collect.
Even as the Cold War was ending, the DEW line was already being replaced by a system consisting mostly of unmanned radar stations (which cut operating expenses 50 percent and spared many Canadian and American air force personnel periods of duty on the coast of the Arctic Ocean). The new North Warning System (NWS) consists of 15 manned long range radars (11 in Canada), and 39 unmanned radars (36 in Canada). This radar system covers an area 5,000 kilometers long and 300 kilometers deep. The DEW line was much longer (going from the Aleutian Islands to Iceland) and deeper (there were two more radar lines farther south, north of the U.S. border.
The DEW Line and the NWS give no warning of ballistic missile attacks, so a different system, using ground and space based radars, has been developed over the last half century. But you still want to know what aircraft are out there over the cold Arctic seas.
A civilian firm provides most of the logistic and technical services to maintain the radars, their generators and communications equipment of the NWS. This costs about $63 million a year. The unmanned radars are marvels of automation, built with many redundant systems, so the radars can remain operational until maintenance crews can be flown in from one of the five support bases. This is particularly difficult during the long, cold and dark Winters.