Science Station Tango Sierra was a Federation scientific research laboratory that was in service in the mid-24th century. This station was located in the Rachelis system. In 2365, the USS Enterprise-D transported a transport container filled with strains of plasma plague from the planet 'aucdet IX to this station. The station's teams were tasked with identifying an antidote for an unidentified plasma plague that was ravaging the Rachelis system. The station received both the container and medical officer Hester Dealt. (TNG: "The Child" )