USS Risa

The USS Risa (NCC-170147) was a Federation dreadnought in service in the early 25th century. 

History
In 2409 the Risa was assigned as the flagship of a Starfleet task force dispatched to the Imaga system to help destroy a doomsday machine under the control of Ambassador B'Vat. The fleet was able to provide enough of a distraction for the Starfleet-hijacked to destroy the leviathan with hargh'peng torpedoes. 

Background
The Risa was almost certainly named for the planet Risa. Its registry number NCC-170147 is the default number for Galaxy X-class ships in Star Trek Online.