Rear Admiral(abbrev: RADM) is an flag paygrade within the Royal Manticoran Navy, Grayson Space Navy, and the Republic of Haven Navy. It holds the equivalent military paygrade of F-2 within The Royal Manticoran Navy: The Official Honor Harrington Fan Association, Inc. and can be a headquarters department head or command of a ship squadron or fleet. A rear admiral is always referred to as a "admiral."
In peacetime, a Rear Admiral would have served as an Commodore, been reviewed by a Flag Officer Promotion Board, approved by the House of Lords, and confirmed by the First Lord of the Admiralty in the name of the monarch. Board review is extremely difficult, as there are a limited number of billets.  Commodores will eventually become rear admirals through seniority. However, there is no guarantee that a billet will be available upon promotion.
If the spacer has completed their Rear Admiral Exam, they are eligible to be promoted to this rank, but needs to confirmed by an Flag Officer Promotion Board. Promotions to Rear Admiral is now only by appointment, if a billet is available that requires it, such as a ship squadron or fleet command as per Admiralty Order 1510-01.
- F-2 equivalents from other branches of The Royal Manticoran Navy: The Official Honor Harrington Fan Association, Inc.: