Deck ListingU.S.S. Valhalla – Due to heavy losses experienced by the United Federation of Planets during its war against the Dominion, Starfleet was facing a shortage of capital ships near the end of the Dominion War capable of leading the fight against the heavily armed Dominion Battleships and Cardassian Union Keldon Class warships. Because of this Starfleet initiated orders for multiple Galaxy Class vessels from shipyards throughout the Federation that would be used to lead Task Groups into battle. Intended to be built with only 25% of her internal components completed, construction was initiated on the future USS Valhalla on Stardate 52685 at the Tellar Prime Shipyards in an effort to make up for losses in the Second Battle of Chin'toka. While she was intended to be spaceworthy and launched in less than a year and a half for combat purposes, the Valhalla was fortunate enough to never see combat in the war that she was built for. With the Dominion War ending with the Treaty of Bajor on Stardate 52902 the 30% completed USS Valhalla was able to undergo a full construction cycle and was launched into the 3rd Fleet on Stardate 54600.
Immediately after her commissioning the Valhalla was pressed into service along with the rest of the 3rd Fleet to face off against the Borg Collective. The Valhalla was assigned to hold the Transwarp Portal captured by the 3rd Fleet in the Delta Quadrant and led forces against multiple attacks by Borg vessels during that period. The Valhalla took extreme damage; however, she was able to assist with the destruction of a Borg Tactical Cube. When Captain Jean-Luc Picard of the USS Enterprise-E ordered a full retreat of Starfleet forces from the region, the Valhalla was one of the last vessels to retreat before the Transwarp Portal self destructed, trapping the remaining ships of the 3rd Fleet in the Delta Quadrant. Due to the severe damage that the Valhalla had experienced in combat, it was towed to the Tellar Prime Shipyards by the USS Atlantis for repairs estimated to last no less than one year. When relaunched in 2378 it was decided that the Valhalla would be assigned to an exploration mission in the northern sectors of the Beta Quadrant.
In 2381 the Valhalla was recalled due to the growing threat from the Borg Collective as they launched an invasion of the Beta Quadrant. Intended to assist with the fleet operations in the Azure Nebula, the Valhalla was delayed due to a malfunction in her Warp Drive which required her to travel at low warp speeds while repairs were made. This saved the Valhalla from destruction at the hands of the Borg during the Battle of the Azure Nebula as all ships, except the Intrepid Class USS Voyager were destroyed. The Valhalla would be diverted to the Ajilon System where it served as the sole defender of the entire system. Using a contingent of Transphasic Torpedoes she was able to destroy a Borg Cube that threatened the planet. It would remain in the system until the end of the conflict as a guardian.
With losses at 40% throughout the Federation, the Valhalla was transferred to the Federation Diplomatic Corps with the responsibility of maintaining Federation relationships with its existing member worlds. It would retain its position in the Diplomatic Corps for the next ten years before being assigned to patrol the Federation's border with the Klingon Empire due to the degradation of the Federation's alliance with its long time ally. The Valhalla would be relieved of service in the region following a near confrontation in the Narrendra Sector that would have led to open warfare between the two governments. Captain Sutran was transferred into command of the Valhalla and she was assigned to the Vulcan Science Academy to assist in exploration missions in the southern Beta Quadrant. She would remain in this role for over 15 years, effectively removing her from participation in the Federation/Klingon conflicts of the 2400s; nonetheless, Valhalla made multiple scientific advancements and established contact with 11 never before encountered races before being ordered to the Utopia Planitia Shipyards for review.
Despite the damage she experienced early in her career it was discovered that the Valhalla had been well maintained for a vessel that was over 40 years old. Because of this Starfleet selected the Valhalla to undergo refit to specifications of the Avalon Subtype of the Galaxy Class. The vessel underwent significant modification to her hull and spaceframe during the period. Due to the massive changes it was agreed that all ships of this subtype would be assigned new registry numbers, but would retain their original names. The Valhalla was relaunched in 2420 and assigned to deep space exploration missions near Cardassian space. It would remain in this role 2426 when it was reassigned to serve as the sector command vessel for the Federation's exploration of the Rakhar Sector in the Gamma Quadrant. Command was transferred to Captain Ken Jamison and the vessel reassigned to the 16th Fleet.