Creator Backlash: Most of the cast hated the costumes they wore throughout the majority of the movie, which have been derisively referred to as "space pajamas" by many. By The Wrath of Khan, this had been fully rectified.
Dyeing for Your Art: Persis Khambatta, who played Ilia, was very reluctant to shave her hair, as it was a huge part of her image. She even asked for insurance on her hair in case it didn't grow back. Thankfully, it did.
Edited for Syndication: For once this was a good thing! ABC helped in financing the movie in exchange for the first Network airings of the film. To get the most for their money, ABC added many scenes to pad out the three hour (with commercials) time slot. When viewers tuned in that Sunday Night, they saw for the first time Uhura defending Kirk's taking over command, the Ensign who beamed up before McCoy, the tear on Spock's cheek as he cried for his 'brother'...in other words all the bits that made it seem like a Star Trek story. Ok...so we also got the Kirk space walk scene with the studio rafters in the background (and in a different spacesuit than in the final version), but hey, nothing's perfect. This version was later released on VHS as a "Special Longer Version".
Real-Life Relative: William Shatner's then-wife, Marcy Lafferty, played Chief DiFalco (who took over for Ilia as navigator after she was...abducted by V'ger).
Screwed by the Lawyers: The shooting was hounded by not one, but two legal feuds, with Roddenberry the target in both of them. Gene found himself becoming an enemy to cowriter Harold Livingston and star Leonard Nimoy, the latter of whom wanted nothing to do with the film; it took literal begging from Jeffrey Katzenberg to get Nimoy into the film, and Livingston had a few contract clauses that were meant to limit Roddenberry's power.
Technology Marches On: According to Dr. McCoy the new Sickbay is like "...working in a damned computer center.".
Even when it was still supposed to have been the pilot episode for the series, Roddenberry and his cowriter, Harold Livingston, had been feuding. His replacement, Dennis Clark (Comes A Horseman) got along even worse with the Great Bird, and Livingston was back in three months. But despite Livingston having it in his new contract that Roddenberry couldn't do any more work on it than he already had, Roddenberry would do rewrites on the sly and then send them to the studio head.
Paramount's original budget was $8 million. The original director and producer were let go once Roddenberry realized just how much the kind of special effects audiences would be expecting after Star Wars and Close Encounters of the Third Kind would cost ... that much, and possibly more. Robert Wise was hired as director and the film's budget doubled. He put shooting on hold while he had the sets and (yes) the costumes redesigned. But the cast, already under contract for the now-abandoned sequel series, was still getting paid every week under regularly extended contracts, and finally Paramount said in late summer 1978 that principal photographry had to start.
Wise didn't want to shoot for more than 12 hours a day, resulting in the production getting behind schedule after the first two days.
Nimoy, at the start of the whole project, was hell-bent against returning to Star Trek thanks to being caught up in his own feud with Roddenberry that was being litigated. When Paramount realized they could not really make the movie without him, then-executive JeffreyKatzenberg flew all the way out to New York to literally beg Nimoy to return. Nimoy settled his lawsuit within a few days and was recast as Spock, but was still on really bad terms with Roddenberry (the experience nearly derailed Katzenberg's Hollywood career period, but he managed to survive to get to Disney.)
The feuding between Roddenberry and Livingston continued, at the expense of the script. William Shatner, who titled his chapter on this in Movie Memories "Star Trek: The Emotional Picture", said the cast was getting revisions every two hours. And they hadn't even settled the question of what was going to happen in the third act, until two months had gone by and Leonard Nimoy began mediating between Roddenberry and Livingston at night after shooting.
William Shatner and Leonard Nimoy both requested rewrites during filming to refine the dialogue as they were both unhappy with what had been written for them ("Kirk wouldn't say this"/"Spock wouldn't say that" etc.).
Grace Lee Whitney (reprising her role as Janice Rand from the first season of the series) recounted in her autobiography that, following a practical joke (which Gene Roddenberry was somewhat notorious for) on Wise that she took part in, Wise forbade the makeup department from proving its services to her. She noted that this is why it often takes a while for viewers to recognize the transporter chief as Rand (while it's easier to recognize her in Star Trek VI: The Undiscovered Country, even though no one refers to her by name on screen).
The visual effects production was a mess in an of itself. When the project first shifted from a television series to a feature film, Paramount wanted to bring in Douglas Trumbull's Future General Corporation (whose founding Paramount had subsidized) to handle the new effects, but FGC had already committed to Close Encounters, which led to the two companies feuding. In the interim, the job went to Robert Abel and Associates.
Only after principal photography was all but done in early 1979 did Wise check on the special effects, of which he hadn't even seen a demo shot (which concerned him). It soon became apparent that RA&A couldn't get the job done (though, in Abel's defense, the frequent rewrites were a contributing factor to the delays)note it should also be pointed out that the company, while initially only brought on to handle the effects, ended up doing things that weren't part of the initial deal, like set and costume designs. Not helped along by Abel using the money (and equipment) that was intended for the movie on commercials and HBO bumpers. By that time, Trumbull had been serving as an unpaid consultant, strictly as a favor to Wise, and it was decided to bring FGC in to take over. However, because of the time crunch (the team now had well under a year to go), Trumbull brought in John Dykstra's Apogee, Inc. to assist. They had to work around the clock to get the job done.
It was so over budget that Paramount executives were keeping a running tab each day of how much it was such (they had trusted Roddenberry despite the fact that he had never produced a feature film; after this they knew better than to let him again).
According to Wise and Jon Povill, the associate producer, the released film was essentially a rough cut that no one had seen in its entirety before shipping. Wise completed the final cut a day before the premier and had to take it with him to the premiere in Washington. The reels were still wet when they were loaded onto the projector.
What Could Have Been: This film's script was intended to be the pilot episode of Star Trek: Phase II, a Sequel Series to the original show that never materialized. The fact that it was written for a 90-minute (at most) pilot episode explains all the padding in the filmed version. Also, Dekker and Ilia would have been major characters in the show, which is why they get more lines than half the actual people the audience came to see. The project got as far as having sets built, test footage shot and scripts for thirteen episodes written before being scrapped. The latter ended up coming in handy when the second season of Next Generation was able to pull several of the scripts out of storage during the 1988 writers' strike.
Also, What Could Have NOT Been: Leonard Nimoy was in an Equus play and by this point, hated Roddenberry, Spock, and Star Trek. Eisner's protege Jeffrey Katzenberg was on his hands and feet to bring Nimoy back into the picture, and he finally accepted, which gave the character of Spock new life.
Chekov was going to be killed by an exploding console during V'Ger's attack on the Enterprise. It was later changed so that he was just injured, and Lieutenant Ilia uses her telepathic/empathic ability to stop the pain in his burned hand.
You Look Familiar: Spock's father is a Klingon Captain! (Although admittedly you wouldn't recognize him unless you knew it was the same actor under the heavy make-up.)
He also looks suspiciously like the Romulan commander in the episode "Balance of Terror", making Mark Lenard notable for being the only actor to have played all three of the major recurring non-human races in the Original Series' canon.