I had seen 'Salt' previously and watched 'Nothing on Earth' the other night.
The journey by dog sled is the most interesting chapter in the film and I found the
visit to the abandoned DEW Line (Distant Early Warning) RADAR station fascinating.
Built in the late 50's, the DEW Line stations were an incredible part of the Cold War.
When you consider that 63 of them were built in just a few short years,
stretching over 10,000km, the logistics were mind boggling. Tens of thousands of
people were involved and the imperative of building them so quickly meant that
construction work would also occur during the dark arctic winters.
The station depicted in the documentary would have been for alerting to a bomber
attack. Shortly after the US built a parallel system called BMEWS (Ballistic Missile
Early Warning System) which deployed three stations.
Because snow would accumulate at a rate of over a couple of feet a year at some
of the arctic DEW stations, they were designed with jack-screws and were hoisted up tens
of meters over their lifetimes. They also drifted with the icecap tens of feet a year
and the structural loading of the snow, ice and melt-water raised safety concerns
for the USAF and so they abandoned some of them by the late 80's and early 90's.
The data from all these stations was funneled back to a network of giant computers,
known as SAGE (Semi-Automatic Ground Environment). Each consisting of tens
of thousands of vacuum tubes, they epitomized the classic science fiction notion
at the time of giant "electronic brains". They were ahead of their time and their ability
to process RADAR data, process it digitally and display aircraft tracks graphically
was a remarkable achievement.
For interested readers, a declassified cold war documentary on SAGE appears here -
http://www.youtube.com/watch?v=06drBN8nlWg
In particular, the demonstration of how the SAGE system worked starting at 15:47
showcases the sophistication of the system.
