In Off Armageddon Reef, Aug YoG 890, Chapter VII, we have the only real description of the OBS.
I'm quoting from the chapter in no particular order.
Quote 1
The kinetic bombardment platforms which had been used against Shan-wei were still there, sweeping silently in orbit around the planet.
End Quote
Quote 2
"Anything more on your analysis of the Rakurai platforms, Owl?" he asked.
"Affirmative, Lieutenant Commander," the AI replied, then fell silent, and Merlin rolled his eyes.
"In that case, tell me what you've come up with on how to take them out."
"I have not been able to devise a plan to destroy them, Lieutenant Commander," Owl said calmly.
"What?" Merlin sat straighter in his couch, eyes narrowing. "Why not, Owl?"
"The kinetic bombardment and solar energy platforms are nested in the center of a sphere of area defense systems and passive scanners which no weapons at my disposal can hope to penetrate," the AI told him.
End Quote
Quote 3
And it's got six loaded cells, each capable of covering half a continent at need, by Owl's best estimate. Not good. Not good at all.
End Quote
The text evidence definitely refers to several kinetic bombardment platforms as well as solar energy platforms and defensive satellites.
My belief is that each kinetic bombardment platform (KBP)is widely separated in orbit from the other KBPs.
Each KBP has one or more solar energy platforms and several defensive satellites.
The OBS is IMO set up so that every point on Safehold is in line of sight of at least one KBP.
The quoted "it's got six loaded cells" may refer to six KBP with the "it" referring to the OBS.
On the other hand, the "it's got six loaded cells" may be referring to one of the KBPs.
In other words, the Orbital Bombardment System is a single system with several KBPs (perhaps six) covering all of Safehold.
On the Gripping Hand, I could be wrong but I await the "Word Of Weber" or further text evidence to show me that I'm wrong.
