Contractors work on the Coast Guard Cutter Polar Star while the cutter undergoes repair work at a dry dock in Vallejo, Calif., June 14, 2018. The Polar Star crew recently completed their mission to re-supply U.S. science operations in Antarctica, escorting the final re-supply ship safely from the ice-covered Ross Sea. U.S. Coast Guard photo by Petty Officer 1st Class Matthew S. Masaschi