Weapon Upgrades
Source Player Core pg. 272
You can personalize weapons by purchasing and installing weapon upgrades, found on the Weapon Upgrades table. Technological weapon upgrades are called weapon modifications, while hybrid weapon upgrades are called weapon fusions. Weapon upgrades are installed into the upgrade slots on a weapon; one weapon upgrade occupies one weapon upgrade slot. The number of upgrade slots a specific weapon has is noted under that weapon's description. You can install a weapon upgrade with the Install Upgrade activity, which takes 10 minutes to perform. Unlike many other types of equipment, weapon upgrades run on kinetic energy created by your body's motion and don't need external batteries. They function only when installed in a weapon you're wielding.
Activating Weapon Upgrades
Source Player Core pg. 272
Most upgrades grant their benefits continually so long as you're wielding the weapon they're installed in. Others produce their effects only when used properly in the moment by spending actions. An activation lists the number of actions it takes and any traits for the activation and its effects. This information appears in the item's Activate entry.
Limited Weapon Upgrades
Source Player Core pg. 272
Some weapon upgrades that have special activations and abilities can be activated only a limited number of times per day, as described in the weapon upgrade. This limit is independent of any costs for activating the upgrade. This limit resets during your daily preparations. The limit is inherent to the weapon upgrade, so if an ability that can be used only once per day is used, it doesn't refresh if the weapon upgrade is uninstalled and reinstalled or is installed in another weapon, or if another creature tries to activate the upgrade.
Weapon Upgrade Limitations
Source Player Core pg. 272
Some upgrades attach to or upgrade a specific part of a weapon. A weapon can only have one such upgrade at a time. These will always be designated in the upgrade's usage entry, such as “installed in a weapon (sight).”
Solarian Crystals
Source Player Core pg. 276
A solarian crystal is a special gemstone grown from the coronal ejections of stars and used to enhance the power of a solarian's attacks. There are two forms of solarian crystals: core crystals and orbital crystals. Core crystals offer the most basic and essential benefits: a weapon potency crystal adds a bonus to the solar weapon's attack rolls, and the striking crystal adds extra weapon damage dice. Orbital crystals grant more varied effects—typically powers that take effect each time the weapon is used.
A solarian can add a solarian crystal to their solar weapon or solar flare by spending an Interact action, and it remains until they remove it with another Interact action. A solarian's solar weapon and solar flare can have one weapon potency and one striking crystal each, plus a number of orbital crystals equal to the value of the weapon potency crystal they're using with their weapon or flare.
Solarian crystal abilities must be activated following the rules for activating items.
A solarian can add a solarian crystal to their solar weapon or solar flare by spending an Interact action, and it remains until they remove it with another Interact action. A solarian's solar weapon and solar flare can have one weapon potency and one striking crystal each, plus a number of orbital crystals equal to the value of the weapon potency crystal they're using with their weapon or flare.
Solarian crystal abilities must be activated following the rules for activating items.
Core Solarian Crystals
Source Player Core pg. 276
These crystals provide essential benefits to a solarian's solar weapon by increasing its accuracy and damage potential.
Orbital Solarian Crystals
Source Player Core pg. 276
These crystals add special abilities to a solar weapon beyond the basics of core solarian crystals. Some orbital solarian crystals affect your solar shot or other aspects of your solar mote instead of, or in addition to, your solar weapon. If a solarian uses multiple orbital crystals of the same type, only the highest-level one applies.