This would be the reason for having a space service:
The competition for the moon between the Unites States and China is being closely watched by the Defense Department as the military expects to play a role protecting U.S. access to cislunar space.
One concern for the Pentagon is the possibility that China establishes a presence on the moon before the United States and tries to set the international rules of behavior in space, said Brig. Gen. Steven Butow, director of the space portfolio at the Defense Innovation Unit. ...
The DIU-led report says U.S. participation in a cislunar economy “will require security and a stabilizing military presence.” That responsibility presumably would fall on the U.S. Space Force. The service would provide “surveillance, aids to navigation, and help when required.”
"Help when required" will require personnel either in space or on the lunar surface. Which means Space Force needs ground troops:
A small special forces ground component is necessary for Space Force. If you want to go after a space station, orbiting satellites for close work, the Moon, or even Earth very rapidly from space. Call them Space, Moon, Orbital, Down teams: SMOD.
... Wait, Space Marines Orbital Detachment! I'm feeling more comfortable with SMOD.
Dusty boots on the regolith will be required to defend America's role on the Moon.
