 She then returned to the Aleutians for the 1942 field season, extending triangulation work as far as the eastern end of Atka Island and hydrographic surveys as far as Seguam Island.During the season, in June 1942, the Aleutians became a front-line combat area after Imperial Japanese Navy aircraft attacked Dutch Harbor and Imperial Japanese Army and Navy forces occupied Attu and Kiska, beginning the Aleutians campaign.After the conclusion of Aleutians work in 1942, "Explorer" returned to survey operations around the San Juan Islands in Washington and performed wire-drag survey work around the Hein Bank with USC&GS "Patton", but during the 1943 season she resumed operations in combat areas in the Aleutians as U.S. and Canadian forces drove the Japanese out of the islands.