The USS Santa Fe has returned to its home base in San Diego ending a six month deployment in the Arctic Circle.
The submarine was used to surface and break through the Arctic ice cap. The Navy says this is a highly dangerous maneuver and is part of an exercise to test the ability of submarines to operate beneath the ice.
The mission was tied to a larger program, known as Operation Ice Camp Boarfish, in which the Navy operates from a drifting ice floe in the Beaufort Sea. The Santa Fe carries a crew of 140 and at 32 years old, it is nearing the end of its service life.