I'm nervous about that approach because it sounds like it would require, or at least strongly encourage, 24/7 patrols of a station, and would benefit only large factions that can afford to do so. This would have the effect of locking other factions out of the territory metagame unless they're willing to make real life sacrifices. This problem is something other persistent PvP MMOs (EVE, Shadowbane, Darkfall, etc.) have all wrestled with, and they seem to have come to the same basic design in the end to solve this problem. I'd like to go over how those games solve it, since I think they're very good at creating significant and memorable fights without forcing their players to reschedule their lives around it.
Major Objectives
Major objectives, like a station, or anything that takes a considerable amount of effort for a faction to build and manage, should be difficult to take or destroy. More importantly, a fight over a major objective should be a
keystone gameplay moment, something that doesn't happen every day but, when it does, creates stories to tell. In order to make this happen, you need to create a fight. A big fight between two or more prepared sides. In other words:
A fight over a major objective should occur between two parties with advance (48+ hour) notice, and at a time that works as a compromise for both sides' time zones (leaning in the defender's favor since they have far more to lose).
Let's take Shadowbane's city sieges as an example. In Shadowbane, a city is normally protected by a Tree of Life that makes the city mostly invulnerable. If an attacker wants to siege that city, they build a (not cheap!)
Bane Stone and place the stone outside of the target city's walls. This Bane Stone does not work immediately. Rather, it declares to the defenders that a siege is going to happen, and the game has a system for the attackers and defenders to negotiate a time 3 days later for it to occur (within a time zone window that works for both parties). This resulted in
big story-worthy fights between two
prepared sides at a time where both parties could commit fully and reasonably to the fight without having to wake up in the middle of the night. This was way more fun than player vs. wall or player vs. door like you get with ninja raiding systems.
Minor Objectives
Since major objectives are rare, and are not always practical or available to fight over, we need something to do the rest of the time. To satisfy this, the game needs minor objectives that are less of a setback to lose and are vulnerable more frequently. Taking Shadowbane again as an example, the game placed persistent ore mines scattered around the map that open to vulnerability on a regular basis (and at different times per mine) that, when captured, yield valuable resources to the controller. Minor objectives give factions ways to further their goals in the territory metagame on a day-to-day and hour-to-hour basis, and gives them something to do, without taking away from the key gameplay moments of major objectives. They also don't require 24/7 attention because losing one isn't a critical blow, it's a more "easy come, easy go" type of objective that's nice to have but you can also afford to just retake later.
EVE does both of these things as well. Player owned starbases (POS) in EVE have a shield that can be put into "reinforced mode", which acts similarly to the Shadowbane Bane Stone in that it provides around two days of invulnerability after the initial sign of aggression (or more if restocked). This allows both defenders and attackers to muster up and show up at a time when both can have a fun and proper showdown over the station. Similarly, EVE has many minor objectives to fight over on a day-to-day basis that provide meaningful PvP and can further an alliance's goals without needing to be a keystone moment or cause a major setback to the opposing side.
Importantly, MMO PvP games are
different from survival games like Rust, Ark, and so on because
the world never resets as it does in smaller-scale games. In survival games, the loss of a major investment is less of a blow because you can try again next server wipe. Not so in Starbase -- there's no "try again next wipe". This stuff really matters. Especially if stations represent major multi-week or multi-month investments of effort to build and develop, as I'm suspecting they will. Defenders should have the right to defend it in full force with advance notice so that, at the very least, you have a story to tell after the fact that isn't just "yeah they took it overnight because we didn't have enough people on shift".