The USS Mars (NCC-525) was a Saladin-class destroyer - of the MK VIIA Siva-subclass - in service in the mid-to-late 23rd century. (Star Fleet Technical Manual)
In 2257, the Mars performed a rescue operation of the USS Diana. Then Lieutenant JG Julienne Cochrane, the ships transporter chief, participated in the rescue. (Tamerlane)
Mars was one of the ships assigned to Task Force Four during the Kelvan War in 2285. (Orion Press: In Harm's Way)
The USS Mars is only referenced in the fan comic Tamerlane.