Vixen, along with Blitzen, was one of two amphibious rovers assigned to the USS Sagittarius in the late 2260s, after the destruction of their predecessors, Roxy and Ziggy.
In 2269, Vixen was chosen to ferry a recon team led by Sagittarius's first officer Vanessa Theriault down to the surface of the planet Arethusa to observe the local Tomol people. To that end, Vixen was rigged for amphibious operations and deposited by the Sagittarius on one of the smaller islands on the planet, from where it would traverse the ocean to the neighboring main island, Suba, and then be stowed and concealed there until Theriault and her team were ready to return to the ship. (Seekers novel: Second Nature)