Mediator - class battle cruiser The " Mediator " - class battle cruiser was an advanced warship developed by the Mon Calamari for use by the New Republic Defense Fleet . Characteristics . The " Mediator " - class was over half the length of the prototype " Viscount " - class Star Defender " Viscount " and was a successor to the previous generations of Star Cruisers , including the MC80 " Home One " type , itself at one point the largest warship in the Rebel Fleet . Like previous Mon Calamari cruisers , they were heavily but conventionally armed with turbolasers and ion cannons , defensive shields and heavy armor , tractor beam projectors , and squadrons of starfighters . Little is known about their overall layout , but one of the ship ' s main hangar bays had an opening on the ventral side of the hull . The armor inside the ship was strong enough to prevent complete destruction of the vessel even in the case of a nuclear detonation inside a hangar . This was in sharp contrast to Imperial designs like the " Imperial " - class Star Destroyer , which could be destroyed with a similar charge placed in a hangar . History . The " Mediator " - class ships were designed after the Black Fleet Crisis as more powerful successors to the previous classes of Star Cruisers built by the Mon Calamari Shipyards , along with the larger " Viscount " - class . The class also represented a move away from the alphanumeric designations which had been given to previous Mon Calamari ship - types , such as the MC80 and MC90 . Instead , they used a conventional class - name based on the name of the lead ship , the " Mediator " . The new battle cruisers were introduced during the Osarian - Rhommamool conflict prior to the Yuuzhan Vong War and saw service in the opening months of the galactic invasion . The class ' s namesake , the " Mediator " , can be considered the first major combat casualty of the conflict : while she was deployed to intervene in a dispute between the planets Rhommamool and Osarian , enemy infiltrator Nom Anor detonated a shuttle laden with nuclear explosives in her hangar section , severely damaging her . In the first months of the war , military analysts like Ayddar Nylykerka , the New Republic ' s head of Fleet Intelligence , believed that the " Mediator " - class ships already in service , when used in conjunction with Bothan Assault Cruiser s and Star Defender s , were sufficient to engage the Yuuzhan Vong successfully , and a " Mediator " - class ship was the centerpiece of a battle group of New Republic and Imperial Remnant warships deployed at Ord Mantell early in 26 ABY , in anticipation of a Yuuzhan Vong strike there . However , during the Battle of Ord Mantell , this ship was destroyed after a vicious close - combat engagement with several enemy vessels , including a " Miid Ro ' ik " . Not much is known of them after this event . Although Mon Calamari was believed to have been cut off before the end of the first year of the war , it appears that secret hyperlane s were in fact kept open , and that new ships continued to be supplied to the New Republic fleets — including the " Mediator " - class vessels to replace those lost and damaged in the opening stages of the conflict . A number of " Mediator " - class ships were part of the combined Alliance fleet guarding Mon Calamari and its shipyards in 30 ABY . The ships served under Admiral Traest Kre ' fey during the Defense of Mon Calamari and were also part of the final assault of the war during the Recapture of Coruscant . Behind the scenes . The size of the " Mediator " - class battle cruiser is uncertain . A lower limit is provided in " " , where a ship of this class is said to be " larger " than a 1 . 6 km " Miid Ro ' ik " , while " " says the Star Defender " Viscount " is " nearly twice the size " of " Mediator " : The " Viscount " length has subsequently been specified as 3 kilometers long in " The Essential Guide to Warfare " , which suggests that the battle cruiser is around 1 , 500 meters long .