Ensign Ravishankar Sabapathy was a 23rd century Human woman, a Starfleet officer during the 2260s decade.
In the year 2267, she was serving as the communications officer aboard the Federation starship USS Defiant when it encountered the cloaked IKS Kretoq. (ST - Seven Deadly Sins novella: The First Peer)
In 2268, Sabapathy was still on the Defiant when the ship was lost in interphase. (TOS episode & Star Trek 5 novelization: The Tholian Web; VAN novel: What Judgments Come)