The Conquest of Space is a 1949 book by Chesley Bonestell and Willy Ley, which inspired a 1955 science fiction film of the same name. We haven't talked about things that way since most of the colonial empires were dismantled. Specifically the Antarctic Treaty of 1961 and the Outer Space Treaty of 1967 ended the practice of grabbing territory by nations that abide by the rule of law. Russia and China haven't got aboard that idea yet.