These are the divisions that are usually stationed at Starfleet Headquarters, but can also be present aboard space stations, starships or Federation planets.
Corps of Engineers
This specialized division handles all Starfleet construction projects in Federation space. Federation shipyards, such as those at San Francisco and Utopia Planitia, fall under its purview. Members of the Corps of Engineers spend most of their assignments planetside or on starbases working on important projects.
Colonization
Starfleet oversees the colonization of new worlds. Its vessels protect new colonies, watch over merchants and freighters delivering valuable raw materials and help out in emergencies. During the initial period of colonization, before a colony government is established, Starfleet may actually run the colony. The colonization division also maintains frontier colonies and regularly patrols these areas.
Diplomatic Corps
Starfleet's Diplomatic Corps, one of its most prestigious divisions, often makes first contact with new races and frequently provides the only UFP representative living on a non-member world. They typically settle disputes between member and non-member worlds, supervise the Federation admissions process and serve as liaisons with allied planets, making them in focus of attention throughout the Federation. This front-line work can often be both physically and emotionally demanding. Successful officers in Starfleet's Diplomatic Corps sometimes become members of the Federation Council.
JAG Corps
Circumstances sometimes require Starfleet officials to serve as judges on distant colony worlds and their own vessels. Normally, a ship captain handles this role along with two other senior officers, but Starfleet also maintains its own military justice system. Each starbase has a Starfleet court, which can administer civilian or military justice.
The Judge Advocate General's Officer investigates alleged crimes and wrong-doings within Starfleet, and represents the accused before a military court. The offenses may range from mutiny or violation of the Prime Directive to conduct unbecoming an officer.
Intelligence
Starfleet Intelligence is responsible for monitoring various threats to the peace and stability of the Federation, drawing its members from Starfleet's main branches. Since much of what it does must remain classified, its operatives do not necessarily mix freely with other officers. After all, they have secrets to protect and operations to manage. Despite the stereotype of spies rendezvousing on distant planets, most of Intelligence's personnel handle standard data collection and analysis, monitoring communications, sensors, satellites and distant probes.
Intelligence does not have operatives in all the places it wishes it could, so it often calls on other branches to help it out. For instance, it may petition Ensign Alessara's commanding officer to assign her to a small shuttlecraft flying near the Neutral Zone in order to watch Romulan military exercises.
