Tessik Prime was the inhabited prime planet in its star system. This system was visited by the crew of Enterprise NX-01 in 2152, as part of their historic mission of exploration. During their visit, Crewman Fisher came down with a case of Rigelian fever, necessitating the inoculation of the entire crew by Doctor Phlox with a vaccine containing millions of genetically-altered microbes. (ENT: "Dead Stop")