Petty Officer 2nd Class Jonny Walker, a marine science technician aboard the Coast Guard Cutter Polar Star, uses a lathe to fabricate a brass bushing for the ship’s propulsion machinery on Tuesday, Jan. 16, 2018. The crew of the Seattle-based Polar Star is on deployment to Antarctica in support of Operation Deep Freeze 2018, the U.S. military’s contribution to the National Science Foundation-managed U.S. Antarctic Program. U.S. Coast Guard photo by Chief Petty Officer Nick Ameen.