Moon Patrol !

 

Interesting piece from the Bulletin of the Atomic Scientists.  In summary, the space race between China and the U.S. could lead to a so-called "security dilemma," where one country builds up its military because of imperfect information about the activities of a potential adversary.  
Sensors will be needed to monitor spacecraft in cislunar space. Earth-based telescopes and radar are insufficient for monitoring the far side of the Moon. Instead, sensors for Space Situational Awareness SSA will have to be placed in space itself.  The Cislunar Highway Patrol System (CHPS) aims to hover between earth and moon. As the moon's commercial and strategic value increases, the CHPS will perform an analogous service in monitoring the cislunar space. This is an eminently practical concern, conceptually at par with maritime domain awareness (MDA) but with space instead of the high seas.

The moon is assumed to be a source of critical materials, including helium-3, which if mined from the moon and brought back to the earth could form a significant source of energy on earth.  Recent breakthrough milestones have been announced in energy fusion research, perhaps offering a glimpse of what may be fought over in a hundred years. 

The Lunar Orbital Platform-Gateway (CHPS) is intended to track spacecraft bound for the moon. It will either protect U.S. interests on the moon, or monitor China's activities there.  The Lagrange point known as L2 offers an ideal location to place a spacecraft as satellites maintain orbit around L2 without expending much fuel.  The US Air Force has announced plans for two spacecraft to explore lunar orbit. The first, CHPS, will be placed at one of the L points. From there, it will track other spacecraft in cislunar space and lunar orbits.  The other is designed to conduct "space object removal and recovery, and other applications in defensive space operations" for the US military.  Inherently dual-use Space debris removal and recovery technology could be employed to interfere with other spacecraft.