Commander Joyaus Dalun in 2415
Commander Rank Insignia
Typical assignments at this rank include executive officer of larger vessels such as the Galaxy and Sovereign class, space station commander (such as Benjamin Sisko of Deep Space 9 prior to his promotion to captain in 2371), and commanding officer of smaller vessels. The rank of commander is also available to chief medical officers and ship counselors who pass the Bridge Officer's Test. An officer who holds the rank of commander is expected to be able to assume command of a starship should the situation call for it.
Officers at this rank typically have a minimum of 10-15 years of experience in Starfleet.