Trivia: This episode was originally intended to be a pilot episode for a spin-off show for the character Gary Seven. This is why Robert Lansing's name appears at the start of the show.
Trivia: At the very end, in talking about the future of the two characters, Spock says, "We could say that Mr. Seven and Miss Lincoln have some interesting experiences in store for them." While this seems like a strange thing for him to say, this episode was a "backdoor pilot" for a spinoff series with the same title (see Teri Garr's Wikipedia entry). But the idea wasn't sold and Mr. Seven and Miss Lincoln never had any further interesting experiences. The Enterprise's history log was evidently wrong.
Trivia: All the action in this episode revolves around McKinley Rocket Base. All footage around the base is actually of Cape Canaveral, Florida, provided to Roddenberry by NASA.
Trivia: The painting on the wall in the office is an actual painting by Reginald Pollack.
Chosen answer: If they're in orbit, they're being pulled along by the planet's gravity well, therefore, impulse engines would only be used for minor corrections and would be "on standby" while in orbit, but not active. (Like keeping your car idling without revving the engine and creating plumes of exhaust).
Captain Defenestrator
Thank you for the info.
Movie Nut