Orion-Class Battlestar (D1)

The Orion-Class Battlestar was first developed and deployed sometime before or during the First Cylon War. Also known as a "Pocket Battlestar" or "Half-Pint," the class appears to be among the smaller ships in the Colonial Fleet, dwarfed even by the Valkyrie type. It may be the smallest Battlestar class to see service.

Layout and Design
Unlike bigger battlestars, the Orion class does not share the same layout and design principles. Instead, the class is built into one main, streamlined body. The Orion class features very little in the way of creature comforts, and suffers from dark, cramped, wet, and humid conditions. Numerous exposed pipes line the halls and CIC, which leave little standing and sitting room, leaving many of the crew to work in tight spots.
 * The upper section: The upper section of the class features the main and secondary batteries, as well as a large conning tower, which features a forward looking viewing area. The class's engine room and sublight engines are housed in the back, above the landing bay. Two more sublight engines are housed in detached cowlings off the main boosters.
 * The lower section: The lower sections contain the main landing bay, Viper launch tubes, main communications tower assembly, fuel tanks, and houses another conning tower with forward facing viewing area.

At least one Orion-Class ship, Osiris, was outfitted with a unique reflective metallic hull which acts as an inhibitor to Cylon DRADIS, and can operate in "stealth mode" within detection range for a short period without being seen. However, as soon as the ship powered it weapons and launched its fighters, the ship immediately became visible to enemy scanners, with the corresponding DRADIS signatures giving away the ship's position. It is not known if this is a standard feature, or a special, one-off design.

Propulsion
The Orion class features four main sublight boosters, two of which are housed in separate cowlings off the aft upper section. The class also features RCS thrusters at key points along the fore and aft hulls. These sublight engines are further augmented with an FTL engine. The overall propulsion design, together with the small size of the Orion class ships, makes the class highly maneuverable, an important aspect of its defensive abilities.

Endurance
Unlike larger battlestars, the Orion-Class is not intended to be used on extended duration missions without the aid of a corresponding battlestar group. The class features limited weapons, which restrict its ability to fight Cylon capital ships. The Battlestar Osiris lasted only a few minutes in combat with a much larger basestar before taking critical damage.

Armament
Ships of this class are moderately armed, with at least thirty-two point defense batteries, twelve primary gun turrets, and multiple missile vertical launch systems, along with Raptors and the potential for a handful of Vipers. The Orion-Class ships are not normally outfitted with planes, and usually take on a compliment from other battlestars. Compared with a basestar, the potential Viper complement is outnumbered ten to one by Raiders.

Crew
The typical crew compliment of an Orion-Class ship is about 150, excluding Viper pilots on detachment from other battlestars.