Combat consists of actions that are used to attack or defend from other players, NPCs, creatures, and other entities. There are a variety of different aspects to combat that are currently implemented.
Arrest and Execution
This is the process where a player captures another player or NPC and then kills them. There are some severe restrictions as to its use, primarily that places where you can perform an A/E are limited by which faction you are in, and what territory they control.
Attempting to arrest another character or NPC will run a skill check of the arrester against a skill check of the defender, and a successful attempt means that the target is then arrested. The arrested player character has only limited access to the game interface, only being able to access the forums and messaging or see their location.
This is a defensive application, used to prevent unwanted passage of players to a planet's surface. If a Shield Generator is linked to a Computer Control Center, then anyone on the Computer Control Center's crewlist will have automatic access through the shield. Shields only prevent travel down to a planet's surface, anyone may ascend up through a shield.
This is a form of combat where player characters use weapons to attack bandit NPCs that spawn on planet surfaces. See Hunting for details and advice for engaging in bandit combat.
Space Combat (Alpha)
Space combat has been released in an "alpha" state and involves Player-controlled squadrons of fighter- and gunship-class ships attacking hostile NPC-controlled ships in deep space asteroid fields. It is not yet possible to die from space combat; however, it is possible for your ship(s) to be destroyed. If your ship is destroyed, it will be turned into a wreck and you will be placed into an escape pod. It is highly recommended that you do not engage in space combat without a full squadron of ships.
Player vs. Player Ground Combat (Beta)
Player vs. Player (PvP) ground combat has been released in a "beta" state in the Derra and Serroco systems. In these systems, it is possible to attack (and be attacked by) other players. While in beta, players cannot fall below 1 HP and cannot attack if they only have 1 HP.