Ion Propulsion:
Menagerie, Del 1:
COMPUTER: Library computer.
SPOCK: Lock on to sensors. Measure object now following the Enterprise.
COMPUTER: Computed. Object is a Class F shuttlecraft. Duranium metal shell, ion engine power
SPOCK: Stop. How long before shuttlecraft's fuel supply forces return to starbase?
COMPUTER: Computed. Shuttlecraft is already past point of safe return.
Spocks hjärna:
KIRK: What do you read, Mister Spock? SPOCK: Configuration unidentified. Ion propulsion, high velocity, though of a unique technology.
KIRK: Any contact, Lieutenant?
UHURA: Hailing on all frequencies, sir. All languages have been attempted. No response. Now using standard interstellar symbols.
KIRK: Keep trying.
UHURA: Aye, sir.
KIRK: Magnification ten, Mister Chekov.
CHEKOV: Aye, sir. Thirty eight thousand and closing.
KIRK: Well, Scotty?
SCOTT: It beats me, but isn't she a beauty?
KIRK: Interesting design.
SCOTT: I've never seen anything like her. And ion propulsion at that. They could teach us a thing or two.