Rianna Mayweather was the medic and chief engineer on the Earth Cargo Service freighter ECS Horizon. She lived on the Horizon with her husband, Mr. Mayweather, with whom she had two sons, Travis and Paul, and one daughter. She usually acted as a mediator between the two brothers when they got into disputes.
She was unhappy when Travis left to serve aboard Enterprise NX-01 but respected his decision. (ENT: "Fortunate Son")
When Travis returned to the Horizon for a family visit, Rianna had to tell him that his father had died and that his brother, Paul, was the new captain. She redecorated Travis' old room, so that it would look like it had when he had left the Horizon. She was always worried about Travis, believing that his career in Starfleet was dangerous. Even so, when Travis told her that he might stay on the Horizon, she told him that his destiny was with Starfleet. When Travis and Paul came into conflict, she explained that it would take time for Paul to become a good captain, just as it had taken the brothers' father. She also convinced Paul to accept several upgrades that Travis installed on the ship. (ENT: "Horizon")