An acting rank is a designation in the Union Fleet allowing an officer to temporarily assume a higher rank with its attendant authorities and responsibilities. Throughout tenure as acting officer, the person is addressed by others as if the full rank were actually held.
Most commonly, an officer of a lower rank assumes command of a ship as acting captain, but officers can assume other positions as well, such as when Doctor Parley assumes command of the Orville's Sick Bay when Doctor Claire Finn leaves for vacation on Arboreus Prime.
- Commanding Officer (Captain Ed Mercer)
- First Officer (Commander Kelly Grayson)
- Second Officer (Lieutenant Commander Bortus)
- Chief of Security (Lieutenant Alara Kitan - Talla Keyali)
- The position of "fifth-in-command" or "Fourth Officer" remains unclear. In addition to the aforementioned officers, there remains two Lieutenant Commander positions: Chief Engineer (Steve Newton - John LaMarr) and Chief Medical Officer (Claire Finn). There have been instances where the first four Commanding Officers have left the ship together. In one instance, the first four Commanding Officers left the ship with the Chief Medical Officer; by process of elimination the Chief Engineer would be placed in command.
Shortly after assuming command of the USS Orville with Commander Kelly Grayson in September 2419, Captain Ed Mercer left Second Officer Bortus in command as he and his First Officer went to Epsilon 2. As acting captain, Bortus led the Orville in an engagement against a Krill destroyer that had came to the Epsilon system to seize the quantum accelerator from the Epsilon Science Station. When Captain Mercer returned to the ship in Shuttle 1, Bortus reported that the ship's upper and middle engines had been taken out, deeming his performance to be a failure. Mercer, however, noted that the ship was still in one piece at least and assured Bortus that he could not have done any better himself.
Bortus took command of the Orville, standing by while Ed and Kelly led a party to investigate the Dorahl Bioship. When he received a distress call from the USS Druyan, Bortus was forced to leave the team temporarily as he took the Orville to rescue the transport ship from a Krill destroyer, doing so successfully before retrieving the crew members from the bioship.
As Isaac analyzed the magnetar AXP 1E 1048-59, Kelly took command as Ed left with Gordon to brief a tactical conference at Outpost 23. During this time, Kelly, at the request of Bortus and his mate Klyden, had their son Topa enrolled in the Orville's school. This led her to meet the teacher, Cassius, who initially clashed with Kelly over Topa entering school at such a young age, only to reconsider after seeing him on his first day, marking the start of Kelly and Cassius' relationship. Soon after, it became apparent that Ed and Gordon did not arrive at Outpost 23 as scheduled. Finding a communications buoy from the BCV Burton, Kelly followed the trace to the Chog homeworld, from where the Orville was struck by an automated Particle Beam Cannon. Thankfully, Ed was able to contact Kelly, warning her not to return fire and thus saving the Chog community.
In orbit of the Sanctuary, Kelly was left in command of the Orville while Ed took Heveena to meet with the Union Council on Earth. When a Moclan Battlecruiser sent shuttles to apprehend the rogue Moclan colonists, Kelly contacted Ed at Union Central; while Ed noted official orders to hold their position, he also unofficially gave her clearance to protect the colony. Kelly took a shuttle to the surface with Bortus, leaving Security Chief Talla Keyali as acting captain. When Kelly's shuttle was caught in a tractor beam by the Moclans, Talla ordered Isaacs to target the Orville's cannons at the Moclans' emitters. Gordon protested this order, noting that it would be an act of war, and urged Talla to contact Kelly for her approval. Talla, however, pointed out that Kelly was already endangering her career by defying official orders, and so she would follow suit. This led to brief skirmish between the Orville and the Moclans, which ended when the Union Council reached an agreement with Heveena and Moclus.
- Episode 1x01: Old Wounds
- Episode 1x02: Command Performance
- Episode 1x04: If the Stars Should Appear
- Episode 1x06: Krill
- Episode 1.5x01: New Beginnings, Pt. 1
- Episode 1.5x02: New Beginnings, Pt. 2
- Episode 2x04: Nothing Left on Earth Excepting Fishes
- Episode 2x12: Sanctuary
- ↑ Episode 1x08: Into the Fold
- ↑ Episode 2x12: Sanctuary
- ↑ Episode 2x05: All the World is Birthday Cake
- ↑ Episode 1x01: Old Wounds
- ↑ Episode 1x04: If the Stars Should Appear
- ↑ Episode 1x06: Krill
- ↑ Episode 1.5x01: New Beginnings, Pt. 1
- ↑ Episode 1.5x02: New Beginnings, Pt. 2
- ↑ Episode 2x12: Sanctuary