Chief Petty Officer Shelby Carlson, the corpsman aboard the Coast Guard Cutter Polar Star, gives training on how to administer fluids intravenously while underway in McMurdo Sound near Antarctica on Thursday, Jan. 11, 2018. The crew of the Seattle-based Polar Star is on its way 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.