Nurse Chapel aids Dr. McCoy in ensuring the well-being of crew and others.
As helmsman, Sulu pilots the U.S.S. Enterprise during its five-year mission. As third officer, Sulu often takes command in the absence of superior officers.
As Captain Kirk's personal yeoman, Rand coordinates all of his personal and professional needs.
Montgomery Scott (“Scotty”)
As Chief Engineer, the no-nonsense Scotty works miracles in repairing and maintaining The Enterprise. Scotty also takes command in the absence of Kirk or Spock.