Other than 'Mechs, Planets are the most important resource in the league. Without them you cannot produce industry or 'Mechs. The following is a compilation of the rules that apply to managing your vast (or not so vast) empires.
Industry is what keeps the league running. A unit without industry soon goes broke and dies. Most of your planets will have some sort of industry on them in some form. From the small 50 million backwater world, to the bustling 500 million Factory/Capital, each adds its own worth to the greater whole. Industry is also used to determine many other features of the league.
Industry may be increased on any planet, up to a maximum of 500 million. The cost of increase is 5-13 c-bills per point of industry. Increases in industry should be carefully made. If you want a strong, well-defended border, higher industry planets will be needed on that border. No risk, no gain. Units with 70+ planets may only have a maximum industry equal to the # of planets X 125 million.
Industry may be moved from planet to planet by use of Transports. Industry may only be moved in blocks of 1 million, each block taking up 2 'Mech slots. Industry may not drop below the Auto-Industry level by using this method. When Industry is loaded or unloaded there is a 25% fee based on the amount of industry and the current industry cost. There is also a small chance of a planet going into Political Instability when Industry is removed due to the native population reacting badly.
Each of your planets is a living, breathing thing. Occasionally they go through economy problems, or maybe a diamond mine is discovered, boosting the economy. As such, during the course of the league you will notice that many of your planets industry levels will vary from month to month. This variation will be small in the grand scheme of things (up to a 25 million change, up or down) but taken together can cause a modest impact upon the league and your strategies.
Political Instability: A planet may go into PI mode either through a successful Guerrilla Raid, or through random government problems on the planet. PI Mode will continue for a period of 30 days, eventually stabilizing on its own. A unit may choose to drop money into correcting the situation though (equal to 50% of planetary industry) at the 20 day mark. Instability effects include:
Units may have any percentage of their 'Mechs in Garrison or Attack status at any time. Having an excessively offensive based force can cause economic problems for the unit to support the scale of their offensive activities.
Planetary 'Mech Limits
Each planet has a Recommended Garrison Limit assigned to it. This limit is based upon the planets current industry at a curve of 3 million for each 'Mech. Inner Sphere and ComStar units have a 2.7 million rate. Salvage effects and industry destruction are only applied to Planetary Assault type battles.
Over-Garrisoning a planet - A planet may hold up to its Recommended Garrison +50%. If RG is 100 'Mechs, then Over-Garrison will allow another 50 'Mechs to be placed. Doing so will negatively effect both the planet, and any battles launched against that planet. These same rules apply for Over-Attacking a planet.
Under-Garrisoning a planet - Like with the Attacker, if you decide to lightly garrison a planet that is PA'd, then salvage BONUSES apply to your unit, up to 75% salvage.
Every planet has the ability to support two types of garrison forces, yours and that of one ally. In order for an ally to garrison one of your planets, they must be set at Full Alliance or Military Alliance on the Diplomacy page. Allied Garrison is counted toward the total number of 'Mechs on planet and any negative effects of Over-Garrisoning still apply. You must have 10 units in Allied Garrison mode in order to gain the following Allied Garrison abilities:
Breaking of Alliance - If your alliance setting drops to Neutral Allied Garrison is in place, several things will happen. First is that the automation will ask you if you are REALLY sure you want to do this. Once you confirm this choice, it will then convert all Allied Garrison between the 2 units to Mothball status. The 'Mechs will be unusable until pulled off planet, or Military Alliance status is restored. If the alliance setting drops further (Border Dispute or War), ALL 'Mechs that either unit has placed as Allied Garrison will launch Guerrilla Raids on the other unit (yes, this means that 20 or 30 battles could be launched in about 5 seconds).
Capital, Factory, high-industry and Charge Station planets are protected by System-Defense Stations. After the 18-hour window has expired on a Planetary Assault, and all Attacker's 'Mechs have dropped, the SD Stations have a 50% chance of forcing a minimum of 25% of the Attacking Dropships to return to their Jumpships. These 'Mechs are not destroyed; only returned to the in-system Jumpships. This can drastically reduce the # of available attacking 'Mechs in a Planetary Assault. The Attacker may attempt to disable the SD Stations by launching a successful Guerrilla Raid before the Planetary Assault, taking them offline for 30 days. SD Stations have no effect on any other battle type. The higher the industry on the planet, the more powerful the SD Stations are. Additionally, all planets with an Industry of 400 million or higher are protected by SD Stations.
The defender may disable their SD Stations through the Planetary Management page. Once disabled, they will remain offline for around 2 days, then they will be reactivated.
If multiple SDS variables exist on the same planet, then the above percentages are all increased by 10% for each variable (4 maximum). Thus a planet with high industry, a Charge Station and a Capital (3 variables) would have an 80% chance of SDS repelling 55% of the enemy forces. A planet with low industry, a Charge Station and a factory (2 variables) would have a 70% chance of SDS repelling 35% of the enemy forces.
Each unit receives one Capital planet by default. Capital planets are the center of your unit's economy and civilization. Capitals of House, Periphery and Clan units are split into a number of sub-sectors. If a Capital Prime planet is lost (taken in PA), then your entire economy will undergo a period of instability representing the chaos that results from the seat of government being destroyed. Every planet in your space will have a 25% chance of falling into Political Instability. At the end of this period, you may choose a new Capital planet within your space. We suggest guarding your Capital well (high industry, large defensive force)
In order to launch a PA on the Prime Sector of a Capital, your unit must already control 30% (rounded up) of the sub-sectors of that Capital. The specific number varies depending on what type of Capital you are assaulting. This represents having a major foothold on the planet.
Terra and Strana Mechty are the primary worlds in the Inner Sphere and the Clan Homeworlds (respectively). Each planet is broken up into 15 sectors. Each of these 15 sectors falls under normal planet rules throughout the league. At league start WoB will own all 15 Terra sectors. The 15 Strana Mechty sectors will be apportioned among the Clans (Prime going to the ilKhan).
All planets in the Kerensky Cluster, Terra, Strana Mechty, all Inner Sphere and Periphery Capitals are split into a number of sub-sectors. Each of these sectors falls under normal planet rules throughout the league. Jumpships may move between any of the the sub-sectors without cost or loss of charge. The movement of the Jumpships represents the use of Dropships to move around the surface of the planet.
Factory specifics are covered under League Economics / Factories.
Factory planets have an additional storage area that can be used to hold 'Mechs awaiting delivery to Jumpships. 'Mechs that are stored in this area are NOT usable in combat. They may be transferred to Garrison status, but once the planet is locked, 'Mechs in the Mothball area are unusable in the planets defense. The Mothball area is NOT locked by a battle. 'Mechs may still be transferred to and from the area (Factory Purchases, transfers to Jumpships). Mothball 'Mechs suffer from increased maintenance costs due to their being kept in a heightened state of readiness (generally always recently purchased 'Mechs).
'Mechs that are ordered from Allied Factories are also delivered to the Mothball Area, one owned by the ordering unit. Those 'Mechs may then be transferred to an in-system Jumpship. Thus several units could have Mothball Areas on the same Factory planet.
Once a battle has been launched, Initial Lockdown begins. Any 'Mechs on planet may NOT be removed from the planets surface (they are stuck there for the duration of the battle). During this time period you may transfer 'Mechs to the planets surface at will. The Attacker and the Defender both can use their Jumpships screen to send 'Mechs to the planet. Failure to do so could result in the 18 hour window expiring, and the battle being lost due to lack of forces.
Full Planet Lockdown occurs 18 hours after the first incoming hostile Jumpship is detected. Once this time period has expired no forces may be transferred either to or from the planet. It is effectively isolated until the battle is resolved. Jumpships may still jump into the system, but they may not continue further into enemy space. They must jump into allied space to continue jumping.
This time window allows for the following to occur:
ComStar Facilities - On planets with upgraded ComStar Facilities present, Full Lockdown is delayed for an additional 12 hours, thus allowing additional reinforcements to be dropped on planet. The locations of ComStar Facilities can be found in the public planet listings.
The above does NOT apply to Trespass Disputes. This is the only battle type to not lock down the Defender's forces on planet.
ComStar Units: For the first month of the league, the planets owned by Word of Blake and Free Rasahuague Republic will not be attackable by Planetary Assaults. After 30 days they are fair game. This is to give time for the IS and Periphery units to figure out their ComStar alliances, as well as for the ComGuard allotment of 'Mechs to be delivered and activated throughout the Inner Sphere.
Unassigned Planets: Pirates frequently make use of Unassigned planets as temporary bases (their capitals). These planets may be attacked, but may NOT be occupied for any length of time. When a successful PA is done against such a world, the planet will remain in the Attacker's control long enough for them to acquire the spoils (salvage, repair, remaining 'Mechs) as well as receiving a cash bonus equal to the current industry. The world will then revert to Unassigned status.