U.S.S. Mariner (NCC-74671-A)

U.S.S. Mariner

USS Mariner
Caelian Class
United Federation of Planets
In Service (2423)
U.S.S. Mariner (NCC-74671)

The U.S.S. Mariner (NCC-74671-A) is a Federation Caelian-class starship operated by Starfleet. Designed as a multi-mission deep space stealth explorer, the ship features cutting edge technology that fits a wide variety of mission profiles.


Mariner is the third Caelian-class ship ever built, completed and launched on Stardate 100255.8, only 11 months after the original prototype. Originally commissioned as the U.S.S. Velian NCC-99105, the ship received special dispensation from Starfleet Operations to be redesignated U.S.S. Mariner NCC-74671-A after the original Mariner was damaged beyond repair during a heroic effort that shielded the Haven and Geki colonies from the Vesuvi supernova and saved over eight million colonists.

The Second Romulan War

Immediately after the Mariner was certified as ready for duty by Deep Space 13's engineering department, an explosive and violent conflict broke out between the Romulan Star Empire and the Romulan Republic. After days of deliberation, the Federation made the decision to formally enter the war on the side of the Romulan Republic.

Mariner's first mission was a combat deployment under Operation Guillotine with Task Force Condor at the Battle of Cero, where Starfleet fought the Imperial Romulan Navy to seize control of the Imperial colony and dilithium mining operations in the Cero system. Despite momentarily losing shields, the ship emerged relatively unscathed with no casualties and contributed to the success of the mission.

After helping to ensure the successful capture of the Cero III colony, Mariner was dispatched on a reconnaissance mission that uncovered the existence of the previously unknown NGC-1716 star system, an Imperial Romulan commerce hub hidden by intense electromagnetic activity.

Technical Data

672 m
195 m
88 m
3,300,000 mt
Avg. Cruise:
Max Cruise:
Maximum Speed:
Warp 8.25
Warp 9.95
Warp 9.99 (for 12 hours)
8x Type-XV Phaser Arrays
2x Type-XV Gimballed Phaser Emitters
4x Torpedo Tubes (2 fore, 2 aft)
2x Type-XV Auxiliary Phaser Cannons (2 fore)
1x Quantum Field Focus Phaser (1 fore)
Deflector Shields
Ablative Hull Armor
Auxiliary Craft:
2x Type 14 Shuttlecraft
4x Delta Class Runabout
4x CMU Workbees

Caelian Class Main Bridge

Physical Arrangement & Crew Support

Crew Lounge, Basic Configuration

Following the success of the Scryer, Phantom, and Eclipse-class design projects in the Klingon War, Starfleet has opted to take a more cautious approach to space exploration following decades of conflict. The Caelian was designed as a ship that could perform autonomous long range assignments while evaluating potential threats from an advantageous position. Based on the successful Vesta-class lineage, the Caelian boasts the same suite of advanced technologies and superior propulsion systems.

The hull geometry of the Caelian is a unique take on contemporary Starfleet ship design, featuring a single body fuselage rather than a distinct primary and secondary hull. To reduce subspace drag on the warp field, the engine nacelles are arranged in a quad layout, with two sets of cowlings joined by a single bussard, suspended on forked pylons port and starboard. This design affords the ship vastly improved aerodynamic and hydrodynamic performance in atmospheric flight compared to its contemporaries.

Caelian-class ships are designed and constructed to be extremely difficult to detect with conventional scans, featuring a composite tetraburnium-monotanium hull alloy inspired by technology encountered by the U.S.S. Voyager during its time in the Delta Quadrant. The hulls of these starships are capable of refracting a wide spectrum of scanning beams from sensor arrays and targeting scanners, as well as resisting high atmospheric pressure gradients, allowing them to operate and maintain stealth in a wider range of environments than a contemporary starship. Unfortunately, due to the thermal and kinetic resistance of the material, the machining process to construct and replace hull plating is significantly more challenging, which can make sourcing parts for extensive repairs difficult.

Thanks to advancements in manufacturing, high resolution sensor pallets that were previously limited to stationary platforms have been able to be shrunken down enough to fit within a starship chassis. The Caelian-class is the first design to receive this upgrade. Two MIDAS multi-spatial sensor array pallets are mounted on the dorsal hull, visually distinct in their blue coloring. These sensors enable unparalleled scanning resolution and bandwidth on a mobile platform, though at the cost of significantly increased energy usage.

In order to accommodate the power hungry sensor arrays, as well as reduce the Caelian‘s overall thermal emissions profile, primary systems were re-manufactured using current generation processing nodes. This reduced overall power consumption by 18%. Large swaths of the ventral hull and nacelle cowlings’ surface area are covered in heat sink grooves designed to facilitate vastly improved radiative cooling. At full power output, the thermal profile of the Caelian-class is comparable to a vessel half its size.

While the lofty goals of integrating larger, more advanced systems and vastly improved thermal dissipation capabilities were met, there were many practical downsides. The interior volume needed to accommodate these changes resulted in a sizeable reduction in living space compared to other Vesta-class variants. Caelian-class ships are only capable of supporting a crew of 400, down from 750, with fewer lounges and holodecks available for recreation. Likewise, in comparison with the Vesta-class, the emergency evacuation capacity was significantly reduced from 10,000 to 7,000.

Tactical Systems

The Caelian's vastly superior radiative cooling improved deflector shield resilience by 20% over the Vesta, allowing for the ship to hang longer in combat situations and better resist the effects of hazardous anomalies in space flight. However, due to difficulties machining hardpoints with the unconventional hull materials, as well as the need to keep the ship's energy signature low, the weapons complement is significantly reduced compared to vessels of similar mass. The ship features only eight phaser arrays and four torpedo launchers, two of which are shielded under retractable hull plates next to the forward mounted auxiliary phaser cannons. In order to maximize firing arc coverage, two gimballed phaser emitters were installed on the dorsal and ventral hull, though their energy throughput is significantly reduced compared to a conventional phaser array.

Thanks to the Caelian's advanced sensor arrays, the targeting scanners are capable of carrying out surgical strikes of unparalleled precision. The wider spectrum of scanning ranges and higher sensor resolution allow it to identify and target system hardpoints and shield vulnerabilities with much finer accuracy. This, in turn, helps the ship maximize the use of its otherwise limited weapons array.

Like the Vesta-class, the Caelian sports an advanced quantum field focuser in its deflector dish to augment slipstream propulsion. This system can be used to channel large quantities of nadion particles parallel to the ship's heading, referred to as a Quantum Field Focus Phaser. The thermal stress of this sustained energy blast is capable of causing significant damage to shields, though the lack of kinetic force limits its destructive capabilities against exposed hull plating.

The full radius of the main deflector dish's emitter array aperture is greatly reduced in scope next to other multi-mission deep space explorers, limiting the ship's ability to manipulate spatial anomalies compared to its contemporaries. The peak energy output of the Quantum Field Focus Phaser is also reduced to 75% effectiveness compared to a similarly sized Vesta.

Stealth Capabilities

Engineered with the best thermal profile management solutions available, energy efficient primary systems, and refractive hull plating, the Caelian is explicitly designed to go unseen. While operating in Grey Mode, its heat and energy signatures are reduced to such a minute output that conventional scans have an extremely difficult time finding it without explicitly searching for its transponder frequency. However, while Grey Mode is effective at masking the ship's presence, the lower energy profile leaves the ship vulnerable with only minimal shielding, passive sensors, no weapons, and a peak speed of ¼ impulse power.

Propulsion Systems

Caelian Class Main Engineering

Much like its multi-mission explorer counterparts, the Caelian is equipped with the most advanced quantum slipstream drive technology available, making it one of the fastest ships in Starfleet at transwarp velocities. The reduced subspace drag afforded by the new engine arrangement and the energy efficiency improvements in its primary systems have allowed the Caelian to increase its conventional warp cruising speed by ¼ of a warp factor over other multi-mission explorers. While the smaller deflector aperture radius reduces its peak effectiveness, the tighter field focus allows for the Caelian to transition in and out of slipstream corridors faster than other vessels.

Command & Control Systems

The amount of computer processing throughput needed to keep the sensor array from stalling primary systems required innovations in data processing. While the underlying computer core architecture is largely identical to that of the latest Brigid-class specification, manufacturing process improvements have resulted in a 17% increase in processor throughput. This change by itself wasn’t enough to prevent the sensor array feed from overwhelming the computer core, however.

In order to accommodate the full scanning power of the MIDAS sensor pallets, Mariner and other Caelian-class ships are the testbed for Starfleet’s new third generation bio-neural circuitry. Taking inspiration from the Borg-inspired systems on the Sagan-class, these gel packs contain self-replicating nanites. The nanites analyze the computer’s processing tasks and systems routines and use the data to dynamically create and destroy circuit pathways, allowing the gel packs to cache immense amounts of data and even independently process tasks, significantly reducing the impact of the smaller crew complement with supplemental automation. This new iteration of computer technology is expected to roll out to the rest of the fleet in waves, starting with refit cycles beginning in 2425.

Scientific Capabilities

With unparalleled scanning capabilities and vastly improved data processing, the Caelian-class is capable of supporting far more advanced simulations in physics, genetics, and chemistry than other contemporary science vessels.




Amathel Tolar


Ruke Warner


Serris Zital


H'ajah, Daughter of Shal


Oliver Bryant


Halur "Hal" Vaas


Rhea Greene


Open Position


Mariner escorting U.S.S. Minerva, pictured 2423