Project Horizon was a study conducted by the United States Army in 1959 examining the feasibility of establishing a military/research base on the lunar surface by the mid 1960s. The idea never got out of the conception stage.
The scientific and commercial justification of a lunar base would be familiar return to the moon advocates today. “Study of the universe, of the moon, and of the space environment will all be aided by scientific effort on the moon. Perhaps the most promising scientific advantage is the usefulness of a moon base for further explorations into space. Materials on the moon itself may prove to be valuable and commercially exploitable.” The same paragraph could easily find its way to a contemporary proposal for establishing a lunar base. But the military justification is interesting, especially given the context of the times, with the Cold War raging and the shock of Sputnik still fresh.
“–it is probable that observation of the earth and space vehicles from the moon will prove to be highly advantageous. By using a moon-to- earth base line, space surveillance by triangulation promises great range and accuracy. The presently contemplated earth-based tracking., and control network will be inadequate for the deep space operations contemplated. Military communications may be greatly improved by the use of a moon-based relay station. The employment of moon-based weapons systems against earth or space targets may prove to be feasible and desirable. Moon-based military power will be a strong deterrent to war because of the extreme difficulty, from the enemy point of view, of eliminating our ability to retaliate. Any military operations on the moon will be difficult to counter by the enemy because of the difficulty of his reaching the moon, if our forces arc already present and have means of countering a landing or of neutralising any hostile forces that have landed. The situation is reversed if hostile forces are permitted to arrive first. They can militarily counter our landings and attempt to deny us politically the use of their property.”
The moon as a military base is not quite a relic of the Cold War as might be thought. As recently as 2010, Taylor Dinerman of the Gatestone Institute suggested that the moon might have military value. “Our planet’s satellite, thanks to its position and its small size, makes it an ideal base from which to explore the solar system, and, if necessary, to dominate the Earth. It has been described as a ‘Gibraltar Point’ possession, which entails control over access to and from the surface of the Earth to the rest of our celestial neighborhood.” Dinerman does not discuss what weapons systems would be placed on the moon that would cause that to happen.
Project Horizon did not lead to a military or any other kind of base on the moon. A recent article in Defense Media Network suggests that there were three reasons.
First, the technological and economic challenges to building a moon base, especially in the 1960s, were far greater than the authors of Project Horizon envisioned. It would have been an effort on the scale that would have dwarfed the Apollo program than landed men on the moon. Even in the context of the Cold War, such an undertaking was hard to sell.
Moreover the United States military had other things on its plate in the 1960s, primarily the Vietnam War. The war sucked up a great deal of resources leaving very little left over for any kind of military base on the moon.
Finally, the Outer Space Treaty of 1967 effectively banned armed military installations on the moon or anywhere else in space.
Thus Project Horizon remains one of those counter factual, a future that never happened.