Visible crew/equipment: As Kirk gives orders to Nomad to lower screens for Spock to examine it, the shadow of the boom mike is seen toward the top of the screen behind Nomad. Also, the wire holding Nomad up is visible.
Visible crew/equipment: When Kirk walks into the brig Spock tells him that Nomad has almost human stubbornness, and that its screens are still up, then just as Kirk moves closer to Nomad the shadow of the moving boom mic is visible at the top, left side of the screen. (00:28:15)
Visible crew/equipment: When the camera looks at Spock after Scott's body is removed from the bridge, the shadows of lighting equipment is visible behind him.
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