Some defense perimeter. The Space Defense Force planners seem to think attacks will only come in from one plane.
Interesting. It seems odd that out of all the ones marked US Defense, Air Force, Navy and Military, only one has a low earth orbit. And only one does a close pass in a larger loop. Perhaps the LOE spy satellites got left off.
And the categories seem kinda off sometimes. For instance; KO-23 listed under "United States". Description says it is South Korean, launched from French Guiana, and funded by the University of Surray/United Kingdom.
How exactly is that a US Satellite?