The modern idea of humans living on the Moon had its origin in 19th and 20th century science fiction literature. While researchers, notably Russian rocket pioneer Konstantin Tsiolkovsky, began to contemplate the technology required to escape Earth's gravity for a journey to the Moon as early as 1890, it was not until 1938-when the British Interplanetary Society completed the world's first scientific study of a lunar space vehicle-that the idea began to interest a wider community of space thinkers and experimenters.
In the decade following World War II, several detailed lunar base studies were published. These concepts captured the public imagination. Arthur C. Clarke's book The Exploration of Space, published in 1951, followed in 1953 by Willy Ley's, Fred Whipple's and Wernher von Braun's book The Conquest of the Moon, presented realistic plans and colorful illustrations showing how humans could travel to the Moon and construct outposts there. "It seems likely that, well before the end of this century," Clarke wrote in 1947, "an attempt will be made to form some permanent colony on the Moon."
By the late 1950s and early 1960s-with the launching of Sputnik, and successful tests of large rockets and humans in near-Earth space-the possibility of men and women traveling to, and living on, the Moon attracted United States and Soviet Union space planners.
In 1959, the U.S. Army Ballistic Missile Agency selected H.H. Koelle with von Braun to complete the first serious, technically detailed plan to construct a lunar base. Classified "top secret" and dubbed Project Horizon, the plan would have used heavy-lift Saturn rockets to place a crew of 12 on the Moon in pressurized underground modules. Abandoned within a year of its introduction, Project Horizon was credited with providing some of the technological framework for the U.S. Project Apollo.
During the 1960s and 70s, both the Americans and Soviets moved ahead cautiously with lunar-base concepts. In the U.S., several studies employed surplus Apollo hardware for returning to the Moon. In the Soviet Union, the Zvezda (Star) concept envisaged six crewmen living in small modules. Ironically, after the first manned lunar landing in 1969, the popularity of returning to the Moon permanently began to wane. However, in 1989, U.S. President George H.W. Bush's Space Exploration Initiative called for a small lunar base by 2008. President Bill Clinton canceled the initiative in 1992, but the idea was revitalized by President George W. Bush in 2004. Now Bush's lunar proposal is being threatened by the current Obama administration.