After the editor creates the first rough cut of the episode, they may decide that additional shots are needed. Here are 6 additional special effects shots, with more colourful storyboards than normal. These may have been shot weeks or even months after the other shots.
Additional Shots for Voyagers Return, Ep 12
Scene 1X. Close up on engine - blue haze + vapour
It seems they added other close-ups. Numerous shots are included throughout the episode.
Scene 2X. Voyager diagonal L-R centre towards very small moon (with blue haze)
Replaces scene 43, at the start of act 2.
Scene 3X. Repeat #2X with slightly larger Moon (with blue haze)
Versions of this shot are seen as the Eagle and Alpha start to shake, before the Queller drive is deactivated.
Scene 4X. Sidon ships towards #2x size Moon
Scenes 4x and 5x seem to replace scene 95 and scene 126 from the original storyboards. Neither shot appeared in their scripted sequence. The first shot is seen between 99 (Helena talks to Queller in Medical) and scene 100, when Bergman brings the Voyager memory bank to Koenig in his office; the second shot is seen after Linden zips up his uniform to leave Medical.
The second storyboard for scene 95 used a much closer moon, as seen here. They obviously decided the Sidons were much too close to the Moon, so 4x and 5x were added with a more distant Moon (similar to the original storyboard). The filmed scene 95 then got shifted up, to just before Bergman says "Linden's using the Queller Drive in short bursts.", replacing another SFX shot scene 137).