1: Flat Ground Defense BonusA planetary shield is an exceptional defensive benefit for a small colony, restricting the available avenues of attack and allowing existing planetary defenses to be far more effective. This benefit tapers off for a large colony, however; it's still useful, certainly, but when your ground batteries already have comprehensive coverage patterns, the addition of a shield is less dramatic.
- Game mechanics: Provides +200 x1.2 ground defense strength, or +300 x1.2 with an alpha core installed, instead of the vanilla x3 or x4.5 multipliers. Note that the flat bonus is multiplied by the normal bonuses from, say, Heavy Batteries, as well as the shield generator's x1.2 modifier; if you want a high planetary defense strength, build both rather than relying solely on either.
- Gameplay justification: This change makes the shield generator actually useful for defense on even a size three colony, while being less overpowering for a size ten colony.
- Credit: Credit for this idea goes to SafariJohn; credit for me knowing about it & thinking to include it in this mod goes to MesoTroniK.
2: -10% Accessibility PenaltyA planetary shield restricts access from orbit to ground; any incoming or outgoing traffic must pass through the shield, and it is not always trivial to open holes on demand.
- Gameplay justification: This cuts into the colony's profitability quite directly, and is a lore-sensible drawback for the advantages the revised shield generator offers.
3: Reduced Population GrowthA planetary shield's access restriction applies disproportionately to population growth, making the arrival of new settlers inconvenient at best. Also, the permanently red sky can be... unsettling. For large colonies, bulk transfers and ever-larger arcology-style habitations makes this effect increasingly negligible.
- Game mechanics: -16 population growth for a size three colony; this penalty reduces by two at each increasing size - -14 for size four, -12 at size five, and so on up to an addmittedly irrelevant -2 for a size ten colony.
- Gameplay justification: This is simultaneously a small penalty and a significant benefit for the player. A penalty because it means shielded colonies can't grow as fast - though it's largely overshadowed by growth incentives. And a bonus because you can build a shield on a size three colony and it will (generally, if it's not in Duzahk or otherwise has extraordinary growth bonuses) stay at size three without requiring the player to periodically scrap its spaceport. This is useful for temporary tech-mining operations or waystation locations that the player plans to abandon.
4: Reduced Terrorist Risk For Non-Freeport ColoniesRestricting surface access to specific places and times makes it difficult to avoid cargo inspections - at least, if your colony bothers to employ customs officials in the first place. The upshot is that - as long as your planet isn't a free port - it is much more difficult for Pather terrorists to establish or maintain a presence on the ground. ...Of course, give them enough motivation, and they'll find ways around even these restrictions.
- Game mechanics: The shield generator reduces "pather interest" values by -9 for the base installation, or -30 with an alpha core installed. As these values are not player-facing, I've included a list of pather interest values (spoiler-tagged in case anyone wants to preserve the mystery). The intent is that the shield generator offers some protection from Pather cells, but that it does not offer free reign to just build everything or install all the alpha cores ever. Please also note that what level of pather interest triggers cell formation can vary with installed mods; there's a limit to the number of active cells, and if you have a large number of faction mods you can get away with more than you could in vanilla.
- Gameplay justification: There is, in vanilla, no real recourse to dealing with Pathers other than to periodically go and smash their stations. Similarly, once colonies are large enough to defend themselves against expeditions, there's no reason not to toggle on free port for the extra income. This addresses both of these issues at once, offering a way to shield yourself from Pather cells... at the price of a significant reduction in potential profitability.
- Pather Interest Values:
Spoiler
AI Cores: +4 for each alpha core; +2 for each beta; +1 for each gamma.
Mining: +1
Refining: +2
Fuel Production: +2, or +6 with a synchrotron core
Tech Mining: varies with the scale of the ruins, up to +8 for Vast Ruins.
Heavy Industry / Orbital Works: +2, or +6 with a nanoforge
5: Reduced Hazard Rating For Colonies With Meteor ImpactsA planetary shield offers a near-total defense against incoming asteroids. Of course, on a planet subjected to regular bombardment, it would be foolish to relax the building codes and rely solely on a shielding system that could fail... or be sabotaged.
- Game mechanics: -25% hazard rating for worlds with the "meteor impacts" condition, offsetting exactly half of that condition's +50% hazard rating penalty.
- Gameplay justification: None. This one's purely here because it makes lore-sense to me.
- Credit: Credit goes to Retry for their post on limited-scale terraforming; everything else on their list, it's easy enough to invent lore reasons why the shield generator wouldn't help... but meteor impacts? That's basically a natural planetary bombardment; pretty much exactly what the shield is designed to prevent.