(coexisting on another dimensional plane) - For the space
station abbreviated as ISS, please see International Space
Station. ISS, short for Imperial Star Ship, was the prefix
designation given to space-faring ships in the Terran Empire
registry and in the Terran Resistance Forces in the mirror
universe. (ENT: "In a Mirror, Darkly, Part II") The use of ISS
as a prefix for Imperial ships was already in use by the 22nd
century, where ships of the NX-class were designated with the
ISS prefix. (ENT: "In a Mirror, Darkly", "In a Mirror, Darkly,
Part II") After the fall of the Terran Empire to the Klingon-
Cardassian Alliance, the use of the ISS prefix wasn't used on
vessels like the Terran raider, but was resumed when the Terran
Rebellion built a Defiant-class starship based on specifications
"acquired" from the prime universe. (DS9: "Through the Looking
Glass", "Shattered Mirror", "The Emperor's New Cloak")