Sombra class
The Sombra class was a type of Federation starship in service with Starfleet during the 23rd century. In 2259, one such vessel was assigned to a mapping mission in non-Federation space. () 

This class was built from the same components as the , and thus closely resembled that class both externally and internally. Sombra-class ships had a smaller crew complement of ninety-nine, and were known for being "fast". The Starfleet pennants of this class had a blue color. They had a larger viewscreen-window on the bridge than the Constitution class. ()

Ships of the class 
  (NCC-1549)
Uncertain

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Federation starship classes