The USS Portia was a Miranda-class Federation starship in operation during the late 24th century. The ship was configured as a "science" variant, lacking the weapons pod "roll bar" of the standard Miranda configuration, instead carrying outrigger sensor "gun pods".
In 2360 the Portia, under the command of Captain Jean-Luc Picard, embarked on a secretive misson to a disputed zone between the Sheliak Corporate and the Breen Confederacy searching for a Manraloth stasis field. They succeeded in finding this artifact on a world they designated Adonis II. (TLE novel: The Buried Age)