This study investigates a thought experiment that reverses the dominant space exploration rhetoric of the 1960s in The Moon is a Harsh Mistress (1966) by Robert A. Heinlein and Solaris (1961) by Stanisław H. Lem. These two works show us the 1960s’ space conquest rhetoric of the Cold War era and the opposite movement for liberty. I discuss how these two works reverse the dominant space frontier-ship, speculating a new world in which they are free from the authoritative atmosphere. In The Moon is a Harsh Mistress, Moon Colony succeeds in getting liberated from the Earth’s federal nations, representing both of the space frontier-ship and its subversion. Stanisław Lem’s Solaris shows that space exploration is just geocentricism, a new version of colony expansion, and tries to find a new way of communication with the others.