Continuity mistake: Lincoln asks Kirk if they measure time in minutes and Kirk replies "We can convert it." In every previous episode they've always used minutes - their ship chronometers are still set to minutes.
Continuity mistake: During the hand-to-hand fight scene, the stunt double playing Spock gets his hair mussed up, but immediately after the fight, Spock's hair is neatly combed and formed, as it was before the fight.
Continuity mistake: In Kirk's log entry, which he somehow makes from jail without a tricorder, he states that 5 witnesses heard him speak to the "spirits." This isn't true, and Kirk ought to know it. The crowd rushed in through an archway after he spoke to Spock and McCoy, and they were all too far away before to hear him. (00:10:50 - 00:26:00)
Continuity mistake: When the prosecutor visits the cell, Kirk's hands on the bars change positions when the camera angle reverses. From the inside, there's one bar between Kirk's hands. From outside, there are two. (00:28:10)
Continuity mistake: After Kirk knocks the jailer out, there's a bit of stew on the cell's door above the lock. After Kirk drags the man into the cell and closes the door, the bar above the lock is clean and dry.
Continuity mistake: Lt. Galloway, who was killed off the season before in "The Omega Glory," is resurrected without explanation for this final episode. (00:24:25)
Continuity mistake: During Spock's Court Martial, Chekov says that General Order 4 is the only exception to Starfleet's no-death-penalty policy, and Sulu and the others agree. However, according to "The Menagerie," that exception is General Order 7, not 4.
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