Sally Bellero was a female Human psychiatrist in the 21st century. She was originally from Tezqan, Peru, and in the course of her career, wrote several papers on space psychology and the possibilities of alien intelligence. As of 2045, Dr. Bellero was Assistant Head of Psychiatry at University Hospital, Marsbase.
In that year, Bellero's identity and credentials were used by Dr. Elizabeth Dehner, a temporally displaced Starfleet officer, in order to gain access to a pair of Vulcans stranded on Earth. As Bellero was still on Mars, this deception wasn't discovered until at least two weeks later. Bellero was recalled to Earth at this time, and interrogated for her alleged role in the aliens' escape from custody. (TOS novel: Strangers from the Sky)