Vulcans are a humanoid species in the fictional Star Trek universe from the planet Vulcan. They are noted for their attempt to live by reason and logic with no interference from emotion. In one episode of Star Trek The Next Generation Android Data and Spock work together to solve a Romulian cypher. .Spock remarks that Data has achieved the perfect Vulcan state of Pure Logic without emotion. Data remarks that Spock despite his efforts still feels emotion which Data is trying to achieve. They were the first extraterrestrial species encountered by humans. They became one of the founding members of the United Federation of Planets. Vulcans are featured in all six Star Trek series, four of which featured a Vulcan as a main character.