1.   But the crews of high-altitude aircraft, especially on polar routes, can receive significant amounts of radiation over time.

2.   The crew flew a polar route to Detroit from Eastern Russia.

3.   But Anchorage was no longer needed after the fall of communism opened the shorter polar routes to international air traffic, and more fuel-efficient jet planes made refueling unnecessary.

4.   The crew was trying to help determine whether the Soviet Union could attack the United States using a polar route.

5.   The study found that use of polar routes would shave more than three hours off existing trans-Pacific routes from the East Coast.

6.   Five hours will be saved by flying non-stop and over a northern polar route crossing Mongolia, China and Russia, Wang said.

7.   Nav Canada estimates a more direct polar route would trim that by about two hours.

8.   The polar route was made possible when Russia opened up air space over its territory, which will allow for longer, faster flights between North America and Asia.