Coast Guard Cutter Polar Star sits on blocks while the cutter undergoes depot-level maintenance in a dry dock facility in Vallejo, Calif., in preparation for the cutter’s future polar-region patrol, April 16, 2018. The crew of the Seattle-based cutter recently returned from McMurdo Sound in support the U.S. Antarctic Program and the National Science Foundation where the cutter's crew broke through more 15 miles of ice in McMurdo Sound, sometimes as much as 10 feet in thickness, to resupply NSF's McMurdo and Amundsen-Scott South Pole stations. U.S. Coast Guard photo by Petty Officer 1st Class Matthew S. Masaschi.