how so?
The moon can provide a more secure base to conduct intelligence monitoring and act as a backup to our satellite communications and GPS systems. I recognize that the moon cannot, obviously, equal our current geosynchronous satellite system that covers the globe. The Chinese are already engaged in developing anti-satellite technology, which could have a serious impact on our ability to employ our weapons systems.
Proposals to use the surface of the Moon for a set of observatories that will both look outwards towards the rest of the solar system and inwards towards the Earth have a definite paramilitary aspect. The size of the apertures that can be created on the Moon are huge and they could produce sets of detailed environmental data that would be extremely valuable for military purposes. Such observatories would be under civilian control, but the products of their observations would be controlled by the nation or nations that built them and thus available for military purposes, just like data from environmental satellites in LEO.
The nature of the new generation of US and foreign “non-kinetic” space weapons is already changing the nature of space warfare. There are basically three types of these weapons: jammers, such at the counter-communications device that the US currently has; disablers, such as medium- or high-powered lasers or high-powered microwaves (HPM) that can disable a target spacecraft; and electromagnetic pulse (EMP) weapons. These last types of weapons are not strictly space weapons since they could also disable electronic systems over large swaths of the Earth as well as knocking out any satellites within range. Since EMP weapons are powered by nuclear explosions they can be classified as weapons of last resort. Any state that used them would have to expect a nuclear response.
In space warfare, it must be assumed that some satellites and spacecraft are going to be destroyed by the enemy. Therefore, it is simply prudent to have reserves in place. So far the GPS system is the only military asset with any significant on-orbit reserves. In the near future the US is going to have to start planning to hide some reserve satellites in cislunar space or even in the “outer envelope” of the Earth-Moon system. Reconstituting a satellite network after an attack will be a lot faster if there are spares already in orbit that can be moved into an operationally suitable position when needed. This may be one answer, among others, to the question of what are “Operationally Responsive” space activities.
We are currently signatories to a 1967 treaty prohibiting the use of the moon for a military base, weapons, etc., i.e.,
First, it contains an undertaking not to place in orbit around the Earth, install on the moon or any other celestial body, or otherwise station in outer space, nuclear or any other weapons of mass destruction.
Second, it limits the use of the moon and other celestial bodies exclusively to peaceful purposes and expressly prohibits their use for establishing military bases, installation, or fortifications; testing weapons of any kind; or conducting military maneuvers.
However, there are plenty of gray areas. I might add that China is talking about establishing a base on the moom.