"You have the Bridge, Number One."

- Captain Jean-Luc Picard to Commander William T. Riker (TNG: "Home Soil")

Among other things, the Starfleet chain of command of a military unit indicated the order of succession of the unit's commanding officer position in both routine and emergency situations across the top ranking officers in the unit. The group of eligible officers could have been described as the command crew, and were typically stationed at the command center of the unit, like the bridge aboard starships or operations center of space stations.

The chain of command was more evident in situations where those higher in the chain were incapacitated, and could not make command decisions or give orders to the members of the crew who could act. The commanding officer role would then have fallen upon the next highest available individual in the chain and they would "take command" of the unit and be considered "in command." When those higher in the chain are capable again of resuming their command duties, they take back command in successive order, all the way back up to the top of the chain where the regular commanding officer resided.

Contents 1 Eligibility and criteria 2 Formal positions 3 Permanent changes at the top of the chain 4 Temporary command transfers through the chain 5 Other command situations using the chain 6 Disrupting the chain 7 Examples of chains of command 7.1 USS Enterprise 7.2 USS Enterprise-A 7.3 USS Enterprise-D 7.4 USS Enterprise-E

Eligibility and criteriaEdit

The regular commanding officer of a unit was assigned by Starfleet to oversee operations of the unit, and that officer would set the rest of the chain of command. The chain could be modified at any time as deemed necessary by the regular commanding officer (or the current commanding officer).

Considerations to where eligible officers were positioned in a chain of command included (in no particular order):

• Rank
• Division/department (those part of the command division are more likely to be near the top)
  • Including whether an officer has any other responsibilities, such as being head of a department
  • Location of standard duty or battle station for one's regular responsibilities (i.e. bridge officer)
• Seniority (usually senior officers are at the top of the chain)
• Command experience
• Captain's discretion (or the judgment of the current commanding officer)
• Starfleet General Orders and Regulations

Passing the Bridge Officer's Test was formally required to take command of a starship (at least for non-command division officers, such as those in sciences division positions, like doctors and counselors) (TNG: "Thine Own Self"), although dire circumstances pushed this prerequisite aside (TNG: "Disaster"), and certain chains might have disregarded this requirement, especially lower in the order.

Conventional practice placed bridge officers higher in the chain of command than non-bridge officers. (VOY: "Displaced")

The scene from Displaced may have been more related to a bridge officer being considered a superior officer to another non-bridge officer with the same rank and similar seniority so that the bridge officer can formally give orders during the situation (like evidenced during the episode) rather than an explicit reference to their positions in the chain of command.

Following the original line of thought, one can rationalize that most operations division officers best contribute to a unit's performance from Main Engineering or other support areas rather than from the bridge, especially when the vessel was in peril. This would also explain why science division officers were not usually seen in command, as their expertise may be best suited to treating casualties from a sickbay or other scientific-specific tasks. Thus, command division officers with command training, especially those working as bridge officers, were left as logic choices for being higher in the chain.

Formal positionsEdit

The higher positions on a Starfleet chain of command were generally referred to as follows:

• Commanding officer
• First officer
• Second officer

The third officer position was not explicitly mentioned in canon in reference to a Starfleet unit, but was referred to as a position on a Klingon vessel (DS9: "Once More Unto the Breach"). However, there have been many Starfleet instances where an officer after the formal second officer needed to take command, and it was typically the same people who where left in command.

If a commanding officer was required outside the first few positions, a discussion may be required by the available crew to agree upon who is the commanding officer after applying the accepted criteria. (TNG: "Disaster")

It was not clear if any positions were formally set after the fourth of fifth officer in all of Star Trek canon, as it may have been impractical to go too much further down the chain on a standard crew complement of hundreds of people with regular personnel transfers, such as on the USS Enterprise-D. It may have been accepted practice to simply deal with this uncertainly on an as-needed basis.

The Jem'Hadar synchronized their rank structure with their chain of command, and went down the line to at least seventh.

Permanent changes at the top of the chainEdit

Formal, permanent changes in the commanding officer position generally required computer authorization via voice commands, and optionally was held as a public ceremony (TNG: "Chain of Command, Part I", "Chain of Command, Part II").

Temporary command transfers through the chainEdit

A transfer of the commanding officer position through a unit's chain of command due to emergency situations was not required to be announced, especially in dire circumstances where the change comes abruptly causing the commanding officer to become incapacitated. Aboard starships, it was common for the new commanding officer to sit in the captain's chair as a symbolic act of the change, not to mention the practicality of easily giving orders to those around the bridge from a central location, and built-in command abilities of the chair itself. Even the Emergency Command Hologram aboard the USS Voyager was programmed to sit in the chair while in command on the bridge (VOY: "Workforce").

The officer explicitly entrusted with command before the previous commanding officer became incapacitated was under no obligation to relinquish command until relieved by someone in higher standing within the chain. (TNG: "The Arsenal of Freedom") However, at least during the 23rd century, Starfleet officers were obligated to relinquish command if ordered to via established Starfleet regulations, even by/to a non-military Federation official. (TOS: "The Galileo Seven")

The scenario witnessed in the TNG episode implies that Geordi La Forge, a command division bridge officer with the rank of lieutenant junior grade at the time, was higher in the chain of command than chief engineer Logan, a lieutenant operations division officer normally stationed in Main Engineering. Alternatively, Captain Jean-Luc Picard simply thought La Forge was the best person to command at the time, and used his discretion to put La Forge in charge, even if there were other officers available, like Logan, so having La Forge ahead Logan in the order may have only been situational. Logan did cite rank and experience in an attempt to get La Forge to relinquish command.

In the alternate reality, a command transfer was initiated by Captain Richard Robau in 2233. As he entered a turbolift to board a USS Kelvin shuttlecraft and confront Nero aboard the Narada, he gave Lieutenant George Kirk orders and left him by saying "you're Captain now, Mr. Kirk." Captain Christopher Pike of the USS Enterprise also relinquished command to another while he obliged to a request by Nero. While he put Spock in command, he also made James T. Kirk first officer to Spock, who relented to Pike's order, at least until he decided to maroon Kirk on Delta Vega. (Star Trek)

It is unclear if anyone held the first officer position during Kirk's absence from the ship, but was the only instance in Trek where the relinquishing commanding officer named a first officer for the new commanding officer.

The temporary commanding officer in such situations was usually referred to holding the position of acting captain, and recorded as such in ship's logs. Traditionally, the individual was called "Captain" by the crew, even if they did not hold that rank nor were the regular commanding officer (DS9: "Behind the Lines").

Other command situations using the chainEdit

By definition of the chain of command of a unit, a new commanding officer was only intended for temporary periods of time to ensure the unit continues to function without the regular commanding officer, or where it was not possible or practical to receive instruction from Starfleet Command. Even in ordinary circumstances, the chain of command was utilized, but it did not mean there was a true change in the commanding officer role, as the standing commanding officer was not incapacitated (merely "indisposed"), so another individual would be entrusted to give command orders on behalf of the standing commanding officer, usually the next available person down the chain (first officer, second officer, etc.) that was available in the command center of the unit.

Traditionally, it would be said that this individual would "have the conn" (TOS: "A Private Little War" et al.), "have the bridge" (TNG: "Home Soil" et al.), "have command" (TNG: "Angel One", "The Arsenal of Freedom"), or even "in command" (VOY: "Twisted"), but was not truly in command unless those above him in the chain became incapacitated. Common examples included:

• A starship's regular commanding officer would still be in command when not physically on the bridge, such as when off duty, in his ready room, or on an away mission. For an away mission, it may be even necessary for the regular commanding officer, first officer, and other senior officers to be off the ship. This could have left a low-ranking bridge officer with the conn (VOY: "Future's End") that may not even had an official spot in the chain.

• Another scenario where many of the senior officers were indisposed was during standard duty shifts, especially later in the shift cycle (TNG: "Data's Day", "Thine Own Self" et al.), and may have even left a junior officer with the conn (VOY: "Night" et al.)

Such an officer could have been described as the bridge duty officer, but was never explicitly done so on-screen; the script for ENT: "In a Mirror, Darkly" does state that Maximilian Forrest and T'Pol shot the duty officer and conn officer when they entered the ISS Enterprise bridge.

Disrupting the chainEdit

One could change or overtake the commanding officer position through Starfleet regulations (such as the chief medical officer relieving the commanding officer as being unfit for duty), or direct orders from flag/superior officers (like those from Starfleet Command).

During the 23rd century events of TOS: "The Doomsday Machine", the "personal authority" of the regular commmanding officer of a unit may be used to overrule a superior officer's orders, even one where the latter officer invokes regulation to take command of the former officer's unit, although there could be consequences for those who side with the regular commanding officer.

Alternatively, a crew could subvert the chain of command by committing mutiny.

The chain typically reverted back after the current situation came to resolution, assuming the original regular commanding officer was still in command and there were no adverse changes to the eligible officers of the original chain.

Examples of chains of commandEdit

Various chains of command utilized on Starfleet starships and space stations have been implemented, many of which changed over time as deemed necessary due to specific missions, conflicts, and personnel changes.

Persons/dates marked with a "*" are presumed to hold a certain position in the chain based on verified chain of command changes of higher individuals. Persons/dates marked with a "^" are not considered valid holders of a position and thus any changes to the positions below it are not represented. Official changes to the regular commanding officer and subsequent changes to the chain are included. Mutinies and other relatively short or informal disruptions to the chain are not included.

USS EnterpriseEdit

USS Enterprise-AEdit

USS Enterprise-DEdit

Year	2364	2365	2366	2367	2368	2369	2370	2371
Commanding Officer	Jean-Luc Picard
				William T. Riker (briefly)		Edward Jellico (briefly)
First Officer	William T. Riker
			Kurn (briefly)		Keiran MacDuff (imposter)^	Data (briefly)
			Shelby (briefly)
Second Officer	Data
						Worf (briefly)*
Third Officer	Tasha Yar	Worf
						Geordi La Forge (briefly)*
Fourth Officer	Geordi La Forge
						Beverly Crusher (briefly)*
Fifth Officer	Worf		Beverley Crusher
Sixth Officer	Beverley Crusher						Deanna Troi

Note: Presumed Crusher was 6th officer at the launch of the vessel given she passed the Bridge Officer's Test in 2362, with no other known eligible officers on the ship at the time.

USS Enterprise-EEdit