(covers information from several alternate timelines)
Vulcan was an inhabited M-class planet in the Vulcan system, a system located in Sector 001 of the Alpha Quadrant. It had no moons, but appeared to have close planetary companions. It was the homeworld of the Vulcans, a warp-capable humanoid species. (TOS: "The Man Trap", "Amok Time"; TAS: "Yesteryear"; Star Trek: The Motion Picture; VOY: "In the Flesh"; ENT: "Strange New World"; DIS: "Magic to Make the Sanest Man Go Mad")
Vulcan was a founding member of both the Coalition of Planets in 2155 and the United Federation of Planets in 2161. (ENT: "Zero Hour", "Demons", "Terra Prime", "These Are the Voyages...") During the Dominion War of the late 24th century, Vulcan's strategic importance was on par with worlds like Andor, Berengaria VII, and Earth. (DS9: "In the Cards", "In the Pale Moonlight")
Vulcan had a considerably higher gravity, thinner atmosphere, and higher temperatures than Earth. Its climate was generally harsh, with most of the surface consisting of large deserts or mountain ranges, along with scattered small seas. Desert areas were prone to large amounts of heat, light, and electrical sandfire storms. By the mid-23rd century, the phrase "hot as Vulcan" had become part of the vernacular. When Doctor Leonard McCoy visited the planet in 2267, he came to understand what the phrase meant. (ENT: "The Forge", "Awakening", "Kir'Shara"; TOS: "Amok Time")
Vulcan was divided into provinces and districts. There were several tourist attractions on Vulcan, including active volcanoes, ancient ruins, and lava fields. When Charles Tucker visited the planet in 2154, he didn't know which site he would look at first. (ENT: "Home"; TNG: "Gambit, Part II", remastered)
Other points of interest include religious sites such as the Temple of Amonak, the Temple of T'Panit, and the T'Karath Sanctuary. (VOY: "Hunters", "Riddles", "Ashes to Ashes"; ENT: "The Forge"; TNG: "Gambit, Part II")
Cities and regions
Points of interest
- Shirkar Academy
- T'Karath Sanctuary
- Temple of Amonak
- Temple of T'Panit
- Vulcan High Command
- Vulcan Institute for Defensive Arts
- Vulcan Science Academy
Land features and formations
- Fire Plains
- Lake Yuron
- L-langon Mountains
- Mount Tar'Hana
- Mount Seleya
- Osana caverns
- Voroth Sea
- Vulcan's Anvil
- Vulcan's Forge
- See also: Vulcan history
Vulcan's earliest contacts with alien beings did not become legends, like in Earth's history. They were known events, and according to Spock, the aliens left Vulcan much wiser. (TAS: "How Sharper Than a Serpent's Tooth")
As early as the mid-20th century, the planet Vulcan had contact with the Tellarites and, covertly, with Humans. By the late 21st or early 22nd century, Vulcans had established contact with the Humans, Cardassians, Klingons, Tholians, and Trill, among others. (ENT: "Carbon Creek", "Future Tense"; DS9: "Destiny")
By the mid-22nd century, Vulcan had a history of conflict with Andoria, controlled the Coridan government, and had exchanged ambassadors with Earth and Qo'noS, among others. After the Babel Crisis, Vulcan became a founding member of the Coalition of Planets before co-founding the Federation in 2161. (ENT: "Broken Bow", "Shadows of P'Jem", "Demons", "These Are the Voyages...")
Very rare among the planet's residents, as she was Human rather than Vulcan, was Amanda Grayson, wife of Vulcan Ambassador Sarek. (TOS: "The Naked Time", "This Side of Paradise", "Journey to Babel", et al.)
As of late 2373, on the eve of the Dominion War, Vulcan's strategic importance for the Federation was on par with worlds like Andor, Berengaria, and Earth. When Kai Winn rhetorically asked Captain Sisko whether he would promise to sacrifice those strategic planets in order to protect Bajor from the Jem'Hadar, he denied this notion. (DS9: "In the Cards")
In 2374, Ishka was given special dispensation by Grand Nagus Zek to leave Ferenginar for Vulcan to have her ears raised. On her way back, she was captured by the Dominion. (DS9: "The Magnificent Ferengi")
Later that same year, Betazed fell to the Dominion, and Major Kira noted that they were now in a position to threaten Vulcan. Shortly thereafter, Kira confirmed that the Dominion had been building up their forces on Betazed and that they would be able to launch an attack on Vulcan. (DS9: "In the Pale Moonlight", "The Reckoning")
In the mirror universe, Vulcan was conquered by the Terran Empire between 2063 and 2155. In that year Vulcans were among the slave races participating in a large-scale rebellion against the Empire, and T'Pol feared that if Jonathan Archer became the Terran emperor, he would use the USS Defiant to crush the uprising and lay waste to Vulcan. (ENT: "In a Mirror, Darkly", "In a Mirror, Darkly, Part II")
- Main article: Vulcan (alternate reality)
- Star Trek films:
- "Where No Man Has Gone Before"
- "The Man Trap"
- "The Naked Time"
- "Balance of Terror"
- "Shore Leave"
- "The Squire of Gothos"
- "This Side of Paradise"
- "Errand of Mercy"
- "The Immunity Syndrome"
- "The Ultimate Computer"
- "Elaan of Troyius"
- "Is There in Truth No Beauty?"
- "Let That Be Your Last Battlefield"
- "The Cloud Minders"
- "The Savage Curtain"
- "All Our Yesterdays"
- "Strange New World"
- "The Andorian Incident"
- "Breaking the Ice"
- "Silent Enemy"
- "Shadows of P'Jem"
- "Fallen Hero"
- "Carbon Creek"
- "The Seventh"
- "Cease Fire"
- "The Expanse"
- "North Star"
- "Proving Ground"
- "Zero Hour"
- "Storm Front"
- "The Augments"
- "Babel One"
- "In a Mirror, Darkly, Part II"
Spock's homeworld was originally to have been Mars. At a time when Vulcans were known as "Vulcanians", their home planet was to have been named "Vulcanis". (Star Trek: The Magazine Volume 1, Issue 2, p. 82) This name was in fact used in an NBC promotional booklet announcing the first season of Star Trek: The Original Series, the 1966/1967 season.  An amended complaint of copyright infringement in the case of Paramount Pictures and CBS Studios vs. Axanar Productions and Alec Peters (the court document was filed on 11 March 2016) erroneously alleged that the name "Vulcanis" was also used to refer to the planet in TOS: "Where No Man Has Gone Before". Although that episode does include mention of the planet, it isn't cited by name on that occasion (with Elizabeth Dehner instead referring to it simply as "your planet" in conversation with Spock). The name "Vulcanis" was used during early production of TOS Season 1 but was changed to "Vulcan" soon thereafter. ("Amok Time" text commentary, TOS Season 1 DVD) The planet was referred to with that name in an ultimately unused line of dialogue from the final draft script of "Mudd's Women" (dated 26 May 1966), in which Kirk admitted to having been on Vulcan (though he didn't go into any further detail about the planet). Whereas the first-produced mention of the planet was in "Where No Man Has Gone Before", the first aired episode to reference it was "The Man Trap", which firmly established the planet's name as "Vulcan".
In Star Trek fandom, intense curiosity about what Vulcan would be like developed during the first season of TOS. Rumors that the planet would feature in an episode of the series' second season leaked to the fans while the first season's episodes were being rerun. That episode turned out to be "Amok Time". (The Star Trek Compendium, 3rd ed., p. 74) The excitement to discover how Vulcan would look enveloped not only fandom but also actor Leonard Nimoy, who was consequently eager to begin work on the episode. "He was really anxious to see what the writer, director and [production designer] Matt Jefferies had come up with in the way of a look for Spock's home planet," wrote William Shatner. (Star Trek Memories, 2009 ed., p. 133)
During the writing of "Amok Time", NBC executive Stan Robertson decided he wanted more of the planet Vulcan to be demonstrated than was depicted in the episode's original story outline. A memo he wrote about his reactions to that story treatment thus included the statement, "The planet Vulcan [....] [has] been built as such a mystery throughout our series that unless we establish more of the planet than is outlined here [...] we will indeed be 'cheating' our viewers." (These Are the Voyages: TOS Season Two, ) Some fans expected "Amok Time" to begin on the planet. Some viewers wanted it to feature a Vulcan city portrayed with new sets and matte paintings. However, these expectations were mostly unrealized, one example being that the episode instead begins aboard the USS Enterprise. (The Star Trek Compendium, 3rd ed., p. 74) Also, the prospect of constructing a high-tech, sprawling city was actually not financially viable for the series, simply being too costly to be practical. ("Amok Time" text commentary, TOS Season 1 DVD) D.C. Fontana, who contributed to the writing of "Amok Time", remembered, "We realized we couldn't show a lot of Vulcan; one of the stipulations for the script was that it be in a relatively tight area, so that we just get a flavor, a feeling." (Star Trek: The Magazine Volume 1, Issue 2, p. 84)
Although the first appearance of Vulcan in "Amok Time" is a view of the planet as seen from orbit, the planet is excluded from the equivalent version of the scene in the episode's revised final draft script, which instead details two consecutive flybys of the Enterprise alone. The script continues with a turbolift scene in which scripted dialogue concerning the planet was ultimately eliminated from the episode, including Spock implying to Kirk that – due to his biology – he can instinctively sense when he is nearing Vulcan. In the first scripted description of an orbital view of the planet, Vulcan is characterized as "a 'hot' planet... yellow, orange... no cool colors about it."
Depictions of Vulcan as seen from orbit in the original version of "Amok Time" featured a reuse of a globe that was often used to represent class M planets but was also frequently reused as various other planets – in which case, it was tinted in a variety of hues, either by an optical printer or by a color timer. The globe's reuses included Deneva in "Operation -- Annihilate!" and Gamma Canaris N in "Metamorphosis".  The remastered edition of "Amok Time" replaced this oft-reused globe with computer-generated shots of Vulcan.
In both versions of "Amok Time", the surface of Vulcan is introduced with a view of a desert area. The episode's script states, "This area of Vulcan is a landscape of drifting sand stretching away to a distant saw-toothed line of mountains jutting up at the edge of the far horizon."
Views of Vulcan ceremonial grounds in the original version of "Amok Time" took their cue from writer Theodore Sturgeon imagining Vulcan culture as highly advanced but with an evolved appreciation for craftsmanship as opposed to high technology. The Vulcan setting was therefore devised as a primitive-looking area resembling Stonehenge, with numerous handmade artifacts (such as gongs, bells, and wind chimes). Sturgeon's method of realizing Vulcan was not only planned to be cost-effective but also emphasized the otherworldliness of the planet. ("Amok Time" text commentary, TOS Season 1 DVD) The script details the ceremonial site as, "A fairly level arena area. Rocks around the edges give a half-natural, half-artifact aspect, as if the wind or rain had curved something like a Stonehenge, or reduced a Stonehenge to something like this. Within this rock area is a Vulcan-made 'open temple.' In history, perhaps it was once a shrine. There are two high arches of stone, a level stone floor an open fire-pit toward the 'rear' as we look at it. IMPORTANT: Several huge jade-like 'wind chimes' hang in view... and as the hot breeze stirs the green, hanging rock together, we HEAR strange musical notes." In scripted dialogue that was not incorporated into either televised version of the episode, the arena is described by Spock as his family's "place for mating."
Theodore Sturgeon's approach to representing Vulcan inspired Matt Jefferies to contribute such embellishments as patches of glistening sand on the ground. Though the setting of the Vulcan temple was much cheaper to show on-screen than a city would have been, it was still considerably expensive, owing in no small part to the fact that most of the rocks and other structures of the faux landscape had to be fabricated from scratch; few of them could be reused from other planet sets. All of the episode's Vulcan set was built on Paramount Stage 32, which incorporated deep red stage lighting to emulate Vulcan's sky. ("Amok Time" text commentary, TOS Season 1 DVD)
Unfortunately, the extensive use of the set to depict Vulcan was extremely evident, even to the extent that overhead spotlights illuminating the area were accidentally shown. (The Star Trek Compendium, 3rd ed., p. 75) Despite the limitedness of how the episode portrayed the planet, Vulcan turned out to be a more peculiar place than most people had expected. (Star Trek: The Magazine Volume 1, Issue 2, p. 84) The Vulcan surface was made to look more extensive in the remastered edition of "Amok Time". Its depiction was inspired by TOS-R Visual Effects Producer Dave Rossi, who was working on the breakdown of "Amok Time"'s visual effects shots while touting the remastered series at a Star Trek convention in Chicago. "I soon realized that the number of times we see the red sky behind the actors was going to make it impossible to treat it in any way. I hated that thing. No background of Vulcan, no definition, just a red curtain," he remarked. "As I was flying back to Los Angeles, it dawned on me that maybe the reason we only see red sky is because the ancient ceremonial grounds were high up in the sky, like on a mountain. I had a friend sketch the idea that this arena of rock had two natural stone bridges that connected it to mountain chains on each side." (Star Trek: The Official Starships Collection, issue 86, p. 16) The new CGI shots of the planet also included a city shown from a distance. The background, encompassing the city, was a painting, whereas the foreground was done by Max Gabl as a three-dimensional render and painted over.  (To view a representation of how Max Gabl created this view of Vulcan, see this video.)
Coincidentally, at around the same time Star Trek was establishing Vulcan in late 1966, the British series Doctor Who featured a story arc, entitled The Power of the Daleks, which featured a planet named Vulcan as a setting.
Vulcan's characteristics of a higher gravity but thinner atmosphere than Earth were inspired by the fact that Spock was already established as having both greater strength and keener hearing than a typical Human. (Star Trek - Where No One Has Gone Before, p. 35)
News that a second Star Trek episode would feature Vulcan was announced at a convention wherein "Amok Time" was first shown to fans. Most of the fans in attendance reckoned that the story would be set mostly at Spock's family abode on Vulcan. (The Star Trek Compendium, 3rd ed., p. 88) Indeed, the planet's surface was originally intended to make a reappearance in that second installment, D.C. Fontana's "Journey to Babel"; for the first time, a city on the planet was planned to be shown. The creation of a matte painting was considered to be prohibitively costly, however. (Babel #5; Enterprise Incidents, number 11, p. 26) The planet's surface consequently appears in only one installment of TOS: "Amok Time". In the filming script of "Journey to Babel", Vulcan is described as a "hot yellow-orange planet". However, in the episode's final version, the planet has a deep red tint.
Vulcan was intended to serve as the primary location of an ultimately undeveloped Star Trek series that would have been centered around Spock and was, shortly after the cancellation of the original Star Trek series, proposed to Gene Roddenberry by Paramount. (The Making of Star Trek: The Motion Picture, p. 18)
Having found the task of bringing the planet to the screen in TOS to have been fraught with difficulties, D.C. Fontana realized a promising means of showing more of the planet. "Any story on Vulcan that came up on the original show faced two problems," she rationalized. "First, all available outdoor location sites looked like Earth – Southern California, to be exact. Second, sets built on the stage suffered from the slightly artificial look all such sets suffer – and we could only afford one major set of this kind. Thus, scope was also limited. Animation, however, would allow us to show the planet Vulcan any way I saw fit. Although it had been established in 'Amok Time' that most of the planet was desert, I wanted to depict other aspects of Vulcan." Thus, the episode "Yesteryear", from the animated Star Trek series, establishes such expansive sites as ShiKahr, which Fontana characterized as "the foremost city of Vulcan." (Babel #5; Enterprise Incidents number 11, p. 26)
When Vulcan is first shown in "Yesteryear", the script describes the planet as having a cloudless, "orangy red" sky, and implies that the lack of clouds is due to the thinness of Vulcan's atmosphere, though what is actually shown in the episode is more of a yellowish brown sky, with many clouds. The script also states that some flowers were imported to Vulcan from other planets, instructs that dust demons were to have been shown, and comments, "While Vulcan is an old planet, its thin atmosphere keeps erosion to a minimum."
A reference to a "family shrine" in "Yesteryear", regarding an area associated with Sarek and Spock's relatives, was meant as an allusion to the Vulcan ceremonial grounds shown in "Amok Time", but this wasn't established on-screen. (Babel #5; Enterprise Incidents, number 11, p. 27)
In retrospect, D.C. Fontana speculated, "Vulcan could probably have been visualized both with locations and on stages [in 'Yesteryear']." (Star Trek Magazine issue 125, p. 83) However, she ultimately found the use of animation to have been "the ideal way" to show such things as the planet. (Star Trek: The Magazine Volume 1, Issue 2, p. 87) "Yesteryear"'s rare views of Vulcan were also welcomed by the fans. (Star Trek Magazine issue 125, p. 81) In fact, the episode's depiction of Vulcan was of such a scale that later productions, even the Star Trek films and spin-off television series with their higher budgets, had difficulty measuring up to it, using location filming and matte paintings. ("Yesteryear" text commentary TAS DVD)
First film portrayal
Writing the planet into the film
Vulcan was intended to be included in the first Star Trek film (which eventually became 1979's Star Trek: The Motion Picture) ever since Gene Roddenberry wrote a treatment entitled The God Thing and submitted it to Paramount in 1975. In that story, Vulcan featured in a limited fashion, with the Enterprise simply taking Spock aboard from the planet. (Lost Voyages of Trek and The Next Generation, p. 9)
Vulcan played a much more central role in another treatment, written later that year by Jon Povill. This treatment involved an ancient psychic cloud – designed on Vulcan as a weapon to elicit discord amidst an opposing army and released from the planet during its final war, centuries ago – causing the Vulcans who now resided on their homeworld to revert to the aggressive moods and other negative emotions of their ancient ancestors, and the Vulcan population consequently choosing to break the planet away from the Federation. The Enterprise traveled back in time to Vulcan's violent past, obtained the psychic generator from a secret compound near the planet's southern pole and returned to Vulcan's present, moments before an all-out war was initiated between Starfleet and the Vulcans, in orbit of the planet. An emotionally positive-charged psychic cloud from the generator aboard the ship prevented the war and Kirk theorized the second cloud had been responsible for the historical change in temperament on Vulcan, though Spock explained that this was not the case. (Lost Voyages of Trek and The Next Generation, pp. 11-14)
Later drafts involved the planet Vulcan to a significantly lesser degree. A third treatment penned in 1975, this time by Gene Roddenberry and Jon Povill, was set in an alternate timeline wherein not only did the Enterprise transfer Spock on board from the planet but also no contact between Vulcan and Earth had ever been made. (Lost Voyages of Trek and The Next Generation, p. 15) One seemingly common factor within these early film scripts was that Vulcan was the place from where Spock was brought aboard the Enterprise; another of the screenplays to feature the planet in this way was Star Trek: Planet of the Titans. (The Making of Star Trek: The Motion Picture, p. 32)
Since the character of Spock had to be written out of Star Trek for Star Trek: Phase II (due to Leonard Nimoy's unwillingness to participate in that ultimately abandoned series), the series' "bible" – the writers/directors guide for Phase II – stated that Spock had returned to Vulcan, more-or-less permanently. (Star Trek Phase II: The Lost Series, p. 84) The planet was absent from "In Thy Image", the story that was intended to serve as Phase II's pilot episode but eventually developed into The Motion Picture. (Star Trek Phase II: The Lost Series) In a meeting that convinced Nimoy to participate in the movie, however, Gene Roddenberry informed him of having had the idea of depicting the Vulcan setting much as it is shown in the film, with Spock having returned there since the ending of the original series. (Star Trek Movie Memories, p. 70) Nimoy, when later interviewed about why he had been the last of the regular cast to sign on to the film, jokingly blamed his late response on the slowness of "the mail service between Earth and Vulcan." (I Am Spock, hardback ed., p. 166) Eventually, he also convinced The Motion Picture's screenplay writer, Harold Livingston, that incorporating the Vulcan setting into the film was a good idea. (Star Trek: The Magazine Volume 2, Issue 8, p. 83)
Physical appearance in first film
In the shooting script of The Motion Picture, the scenes on Vulcan are said to be set during daytime, yet the theatrical cut of the film consistently shows the planet with black, starry skies. As scripted, the planet was to have been introduced with the camera moving through thick, steamy clouds before the planet's surface would have been shown. The script details the mountainous Vulcan landscape as having "harsh, strange angular peaks and rock formations," and the planet itself as being "barren" as well as "legendary". Although the film itself shows Spock moving between two different areas, this does not happen in the shooting script, which instead describes only one location; Spock was to have been located atop a stone platform or ledge amid ruins, "facing a semi-circle of three similar platforms" (for the trio of Vulcan masters), with "gigantic ancient Vulcan statues and ruins" in the background. 
During the months of pre-production on The Motion Picture, director Robert Wise and production illustrator Maurice Zuberano – interested in finding a location to represent Vulcan – searched through numerous books depicting distant natural wonders and/or ruins, at sites such as Afghanistan, Tibet, and Turkey. Ancient temple ruins in a remote area of Turkey were at one time seriously considered for use as Vulcan. A venture to such exotic locales was considered to be too expensive, though, so this idea was scrapped. (The Making of Star Trek: The Motion Picture, p. 172)
The presentation of Vulcan in the theatrical cut of The Motion Picture involved matte paintings done by Matthew Yuricich. "He had almost no time to do them, so he was never quite happy with them," noted Robert Wise. (audio commentary, Star Trek: The Motion Picture (The Director's Edition)) The Vulcan settings were also included in storyboards and, prior to the planet's sky being depicted as black with stars, an early matte painting (worked on by Yuricich) showed the planet with its more typical golden sky, an illustration that was abandoned in 1979. Producer David C. Fein later reasoned, "As far as we can tell, they went for a darker environment because it helped to hide the fact that the Vulcan elders were actually speaking English and not Vulcan." (Star Trek: The Magazine Volume 2, Issue 8, pp. 25 & 26) Visual effects supervisor Daren Dochterman suspected that the replacement of the sky from orange to starry black implies that the film's original production staff must have had a problem with integrating the early matte painting with live action footage that was used to represent parts of the Vulcan landscape. (Star Trek: The Magazine Volume 2, Issue 8, p. 59) Two matte paintings represent Vulcan in the theatrical cut.
The first of these illustrations includes a tiny portion of footage of Spock, which was filmed in one of Yellowstone National Park's geyser fields. (audio commentary, Star Trek: The Motion Picture (The Director's Edition)) This was at Minerva Hot Springs in the northwest corner of Yellowstone, which had been chosen instead of a location further afield. (The Making of Star Trek: The Motion Picture, p. 172) The area was scouted by Maurice Zuberano and Photographic Effects Project Manager John James. They took photographs of Minerva Hot Springs from every possible angle and successfully negotiated for the Park Department's permission to shoot the Vulcan scenes there, even though it was at the height of the summer tourist season. To limit the danger of the production crew affecting the delicate geological formations in the area, crew setups were at first confined to the park's boardwalks, though the Park Department later constructed an additional platform to specifications from the film's art department. The photographs taken at the location had clearly shown that only one angle was suitable for the filming. Michael Minor also quickly journeyed to the area, after which he started design work on the Vulcan scenes, creating a large painting of how the planet might appear in the film. On 8 August 1978, Minor returned to Yellowstone – intending to help capture the location footage – along with ten other individuals, including Leonard Nimoy, Matthew Yuricich, John James, second unit cameraman Jim Lyles, and location special effects coordinator Joe Viskocil. The location shoot lasted three days. (The Making of Star Trek: The Motion Picture, p. 173) Ultimately, Robert Wise was of the opinion that, in this first wide shot of the planet, Spock was hard to identify amid the vast Vulcan surroundings, and both Wise and Gene Roddenberry felt there wasn't a strong enough link between V'ger, which appears in the shot immediately before the Vulcan scene, and Spock. (audio commentary, Star Trek: The Motion Picture (The Director's Edition))
The second matte painting includes a red statue that is shown from waist height and a full view of another statue that is shown from its right side. A flight of stairs in this shot was actually a small, three-piece model created by Mike Minor and production designer Harold Michelson. This miniature was two foot deep by six foot wide and consisted of two-by-two-foot modules bolted together. (The Making of Star Trek: The Motion Picture, p. 173) The second matte painting does not completely correlate with a live-action close-up shot that precedes it; although the close-up shows Spock shielding his face from the sun with his left hand, there is no sun in the painting (which, on the contrary, shows very little sky). The mismatch between these two shots meant that, for some viewers, determining what the wide view was meant to portray was somewhat problematic. ("Re-Directing The Future", Star Trek: The Motion Picture (The Director's Edition) special features) Daren Dochterman opined, "It's really confusing as to what you're actually looking at." (Star Trek: The Magazine Volume 2, Issue 8, p. 59) Doug Drexler concurred, "I don't know about you, but when I saw that sequence in the film, I couldn't make head nor tail of what I was looking at." (X)
The close-ups in this Vulcan sequence were shot on the Paramount lot, in what is known as the "B Tank". By the time the production crew filmed in this area, the location filming in Yellowstone had been completed; the art department were initially faced with the task of somehow recreating that setting on the studio lot. A similar requirement, once the B Tank was selected as the filming site, was that the proper angle for constructing the set had to be decided, as the sun had been shining on Leonard Nimoy's face at the location. About a month prior to the start of construction in the B Tank, Mike Minor determined the final position for the set, extrapolating where the sun would be, using one of numerous quarter-inch mock-ups that the set designers had of the Vulcan scenery, a miniature that Minor took to the B Tank. Working from the set designer's plans, metal platforms and an upper plywood base were built, giving the general impression of the rocks. Chicken wire was added for support before the framework was blown over with a polyurethane foam coating, which was subsequently left to dry and then painted to match the Yellowstone version. (The Making of Star Trek: The Motion Picture, pp. 176-177) Special effects supervisor Alex Weldon was charged with devising a way to realistically recreate the look of pools of steaming milky water that had been at the location. He concocted similar liquid with evaporated milk and white poster paint, mixed with water and poured into the set's pools. Steam bubbling to the top was created with dry ice and steam machines, passed into the water via hidden tubing. (The Making of Star Trek: The Motion Picture, p. 165) Although the filmmakers had at their disposal a large backdrop that was painted like the sky, they decided not to use it for the Vulcan scene. They opted to position a giant red boot in the B Tank, however, which matched the red statue's full-size leg in the second matte painting. (audio commentary, Star Trek: The Motion Picture (The Director's Edition)) The boot was sixteen feet high and made from Fiberglas. (The Making of Star Trek: The Motion Picture, p. 177) The total cost of constructing this planet Vulcan set was US$42,000. (The Making of Star Trek: The Motion Picture, p. 95) (Additional images of the B Tank in its Vulcan configuration can be seen here(X).)
Revision for Director's Edition
Foundation Imaging, under Robert Wise's supervision, revised the two matte paintings for the director's edition DVD of The Motion Picture. Wise recalled, "We started from scratch, took a look at what was already established about Vulcan from the original show." (audio commentary, Star Trek: The Motion Picture (The Director's Edition)) Continued Daren Dochterman, "We went back and saw the original storyboards, and they seemed to work well with the footage that had already been shot." (Star Trek: The Magazine Volume 2, Issue 8, p. 59) Both of the newly created matte shots were consequently based on the storyboards whose envisions of the Vulcan landscape had been discarded from the film's theatrical cut. ("Re-Directing The Future", Star Trek: The Motion Picture (The Director's Edition) special features; Star Trek: Communicator issue 136, p. 27) Foundation also incorporated the live-action plate photography that had originally been filmed for The Motion Picture, combining it with their digital matte work, and colorized the Vulcan skies almost consistently orange. (audio commentary, Star Trek: The Motion Picture (The Director's Edition)) In this way, the revised matte paintings were designed to more closely resemble the planet's surface as depicted in Star Trek III: The Search for Spock. (text commentary, Star Trek III: The Search for Spock (Special Edition) DVD) Sherry Hitch, from Foundation Imaging, commented, "We blended a lot of elements, Dave [Morton] and I. He did... I'd say, ninety percent of the work, though." The entirety of the Vulcan settings was created in three-dimensional digital imaging, which enabled Morton and Hitch to tweak the elements of the newly visualized scenery. ("Re-Directing The Future", Star Trek: The Motion Picture (The Director's Edition) special features)
Adding a tilt from the Vulcan sky to Spock's position in the new version of the first matte painting made the character more noticeable and strengthened the sense of connection between him and V'ger, visually shifting from the cloud's position to the Vulcan landscape where Spock was. (audio commentary, Star Trek: The Motion Picture (The Director's Edition)) The pan down from the sky also involved the sky's color brightening from the black of open space to the orange of the Vulcan sky as seen from the surface.
For the second new matte shot, the restorers not only added the Vulcan sun but also chose to cluster the area with Vulcan artifacts, incorporating an ancient Vulcan temple into the shot and redoing the statues. All of these elements were planned for in the earlier storyboards used by the team. Even though a test version of the second digital matte painting included a pair of newly envisioned statues (their quantity matching those in the theatrical cut), two more statues were added for the final shot, as was a Vulcan lirpa, held by one of the two preexisting statues. ("Re-Directing The Future", Star Trek: The Motion Picture (The Director's Edition) special features) For this sequence, a total of six statues were designed by Doug Drexler, who was thrilled that Daren Dochterman invited him to participate. (X) The quantity of Drexler's statues matched the number of sides to stones on the Vulcan ground, which can be seen in the close-up shots. Drexler also incorporated the same six-sided shapes into the costumes on some of his statues.  (Concept sketches of the statues can be viewed here(X).)
As Doug Drexler and Daren Dochterman were among those who had found it difficult to make out what the original second matte painting was meant to show, they were both satisfied with the revision. ((X); "Re-Directing The Future", Star Trek: The Motion Picture (The Director's Edition) special features) Indeed, Dochterman was highly pleased with the modified view, calling the new orange sky "beautiful" and the new statues "gorgeous." ("Re-Directing The Future", Star Trek: The Motion Picture (The Director's Edition) special features) He also termed the general landscape "really beautiful" and concluded, "It turned out really nicely." (Star Trek: The Magazine Volume 2, Issue 8, p. 59) Robert Wise enthused, "We have a much more dramatic sense of the Vulcan landscape with these giant ancient statues all around." (audio commentary, Star Trek: The Motion Picture (The Director's Edition)) Regarding the Vulcan scenery as depicted in the pair of newly created shots, Sherry Hitch remarked, "It's awesome." ("Re-Directing The Future", Star Trek: The Motion Picture (The Director's Edition) special features)
Appearances in later films
An initial story outline for Star Trek III featured the Enterprise paying an early visit to Vulcan, prior to heading to Earth. This trip to the planet, taken so that McCoy could have a restful leave of absence on Vulcan, was against orders, as many of the planet's citizens were dissatisfied with the Federation having such a powerful weapon as the Genesis Device. The scene and much of the related material, which were ultimately deemed unnecessary, were removed from the story by Harve Bennett, who had originally written the outline and went on to write the film's script. Although the planet appears in the film's conclusion, the outline did not feature Vulcan reappearing and instead ended in orbit of Earth. (Star Trek: The Magazine Volume 3, Issue 8, pp. 29-30 & 31; Trek: The Unauthorized Story of the Movies, pp. 82 & 84)
Star Trek III required not only Vulcan but also, in the words of Harve Bennett, "the size thereof." (audio commentary, Star Trek III: The Search for Spock (Special Edition) DVD/Blu-ray) Thus, the film's director of photography, Charles Correll, argued in favor of shooting the movie's Vulcan scenes in Red Rock Canyon, wishing to avoid a "phony" look. (Cinefantastique, Vol. 17, No. 3/4, p. 84; The Making of the Trek Films, 3rd ed., p. 57) Believing that the events on Vulcan at the end of the film were very important, Leonard Nimoy – who not only played Spock in Star Trek III but also served as the movie's director – wanted the planet to be shown with big sets. Nimoy was pleased with the opportunity to depict the planet on such a grand scale. "To the director, the delight of the visuals of the Vulcan scene, especially by a Vulcan director," Harve Bennett commented with a laugh, indirectly referring to Nimoy's double duty in the movie, "to show his homeland and its culture in such rich detail, [was] marvelous." (audio commentary, Star Trek III: The Search for Spock (Blu-ray)/(Special Edition) DVD)
Concept paintings of Vulcan were created for the film by Industrial Light & Magic, some of which featured primarily blue versions of planetary scenes. (The Art of Star Trek, pp. 224 & 225) Charles Correll aimed to colorize Vulcan with deep oranges, however. "We wanted the planet to look like it was always sunrise," he stated. (Cinefantastique, Vol. 17, No. 3/4, p. 84; The Making of the Trek Films, 3rd ed., p. 57) Vulcan's appearance in Star Trek III incorporated several matte paintings provided by ILM. Both that effects house and the film's art department worked on the designs for Vulcan. (Star Trek: The Magazine Volume 3, Issue 8, pp. 27 & 51) As such, Tom Lay – one of the production illustrators assigned the task of collaborating with ILM – worked closely with the group on the Vulcan sequence. (The Making of the Trek Films, 3rd ed., p. 53)
A backing which Tom Lay created for Star Trek III and which showed Vulcan mountains as viewed from Mount Seleya ended up being used as the planet surface elsewhere in the film, apparently in an initial panning shot of Vulcan. "They put some smoke and lighting and we got a mood piece out of it," said Lay. (Cinefantastique, Vol. 17, No. 3/4, p. 68) The same shot incorporated some other elements. ILM's Kenneth Ralston, the film's visual effects supervisor, explained, "We have some foreground pieces that we shot separately, which pass in front of the camera to give just a slight multiplane effect and a little more depth." (Cinefex, No. 18, p. 67)
The collaboration between ILM and the art department at Paramount was not an easy one, with the responsibilities of each team occasionally being unclear, such as who should deal with depicting the Vulcan landing area for the film's Klingon Bird-of-Prey. (Star Trek: The Magazine Volume 3, Issue 8, pp. 27, 54 & 51) This landing site was ultimately filmed on location at Occidental College in Los Angeles, where a facade was erected on the steps of the school. (Cinefantastique, Vol. 17, No. 3/4, p. 84) Ken Ralston noted, "It was simpler than trying to build something, especially with their tight budget." (Cinefex, No. 18, p. 67) The location shoot was over a stretch of two days. (text commentary, Star Trek III: The Search for Spock (Special Edition) DVD) However, the Vulcan scene had to be filmed at night, which meant that lighting the location was not simple. Charles Correll explained, "In order to accommodate the ILM plates and opticals, it required a tremendous amount of exposure. So, we had to send away. There was one light that they were using in England at the time – a cinematographer by the name of David Watkin had built this huge light for night exteriors – and we actually had to emulate that and build our own. And it was this huge light. It was called the Wendy Light, and we had to put it up with a construction crane." (audio commentary, Star Trek III: The Search for Spock (Blu-ray)/(Special Edition) DVD) Ralston said of the location footage, "We shot it around two in the morning; and being a latent image shot, everything had to be done in the camera, so we had to be very careful about what we were doing. It took forever to set it up." After the filming at Occidental College, smoke was super-imposed into the latent image shot. (Cinefex, No. 18, p. 67) A small portion of the Vulcan landing scene was filmed weeks later, on Paramount Stage 4. (Star Trek III: The Search for Spock - Handbook of Production Information)
Some of the film's scenes had to be trimmed or outright deleted, the majority of which took place on Vulcan. (Star Trek Monthly issue 26, p. 35) The sequences that involved the planet but were not used were mostly based around a Vulcan procession moving Spock's unconscious body from the landing area to the top of Mount Seleya, such as in a never-filmed barge scene for which ILM art director David Carson created a conceptual illustration. He remarked, "We wrestled quite a bit with trying to come up with an impressive number of environments that you pass through that could be constructed for a reasonable budget, and ultimately we failed! [....] I did this great drawing – it's a bunch of people on a submerged river, poling along on this barge. I knew as I was drawing it there was no chance. When Harve and Leonard [Nimoy] looked at it, they said, 'Yeah, that would really be great but there's no way.'" Another Vulcan setting that was designed for Star Trek III but never shown in the film was the Hall of Ancient Thought. (Star Trek: The Magazine Volume 3, Issue 8, p. 54)
Ultimately, Ken Ralston was highly pleased with Star Trek III's portrayal of Vulcan. "It had an interesting look to it," he observed. "It's not reality per se, because the situation is so fantastic, and the layout of the place is almost dreamlike. But the continuity of the sets and the effects and the color work very well together–it fools you into believing it's much more real than it would have been if they had shot it in the Mojave Desert and then we'd have cut to a painting with a whole different set of values [....] The matte guys did some fabulous stuff here." (Cinefex, No. 18, p. 67)
Following a shot of Mount Seleya that was actually a reused matte painting from the previous film, Star Trek IV's depiction of Vulcan continues by incorporating some shots of and around the landed Bird-of-Prey, the HMS Bounty. Live-action footage involving the base of the ship was filmed outside, in a Paramount parking lot. (Cinefex, No. 29, p. 6) Recalled Leonard Nimoy (who returned as director for Star Trek IV), "We searched high and low for a location for this sequence [....] We looked at various canyons, we looked at desert. And there were always problems. Either the look wasn't right, or it was too far out of town or whatever. And we ended up shooting it on the Paramount lot. And the set construction people and design people did a great job of camouflaging whatever we didn't want to see. They did it with smoke or a piece of a set, or a flat or some painted canvas or something to hide the background, to hide the buildings that [were] within thirty feet of us." (audio commentary, Star Trek IV: The Voyage Home (Blu-ray)/(Special Edition DVD) To represent the surface of Vulcan, tons of reddish dirt and sand were brought in to this area of the lot. Writer Howard Weinstein, who was visiting the set when these live-action components were in place, later remembered, "I half-kiddingly contemplated scooping up some red dirt and taking it home to package and sell at conventions as 'Real Vulcan Sand.'" (Star Trek Magazine issue 165, p. 50) As well as incorporating live-action plates, the footage of Vulcan showing the grounded Bird-of-Prey was largely a matte painting by Matte Artist Frank Ordaz. (Cinefex, No. 29, p. 9) A shot of Spock looking down towards camera from atop a rocky cliff was shot on location at Vasquez Rocks. (text commentary, Star Trek IV: The Voyage Home (Special Edition) DVD)
As the director of Star Trek V: The Final Frontier as well as a co-writer of that film's story, William Shatner originally envisioned the setting of the movie's illusory cave sequence to be in a dark cave where the mysterious birth rites of Vulcans took place, concealed from the outside world. This cave was built as part of the set for the film's forward observation room. (Captain's Log: William Shatner's Personal Account of the Making of Star Trek V: The Final Frontier, pp. 159 & 157)
In common with "Journey to Babel", the episodes from Star Trek: The Next Generation that featured Vulcan mostly showed only views of the planet from orbit, excluding Vulcan's surface from reappearing. Two such shots of Vulcan are shown in "Sarek", whose script described the planet as "red/brown." However, the same teleplay gave no indication that the planet was to be seen in any more than one shot.  The second of the three TNG installments that feature Vulcan, "Unification I", was the first time a room on the planet was shown without the exterior of the planet's surface being depicted too.
Due to the premise of Star Trek: Voyager, Vulcan couldn't periodically be shown as a setting in that series. (Star Trek: Voyager - A Vision of the Future, p. 164) For Vulcan's appearance in the Voyager episode "Persistence of Vision", stock footage from Star Trek IV: The Voyage Home was used. (Delta Quadrant, p. 77)
In an early version of DS9 Season 4 two-parter "Homefront" and "Paradise Lost", Vulcan seceded from the Federation, as the Vulcans objected to the Federation becoming increasingly security concerned about the danger of Founder infiltration. Also in the story, the Federation, due to the Vulcan breakaway, developed a suspicion (ultimately proved wrong) that there were Founders on Vulcan. (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages, p. 112)
At the start of Star Trek: Enterprise, Rick Berman and Brannon Braga established that Vulcan had an antagonistic relationship with Earth. This idea extremely appealed to married writing couple Garfield and Judith Reeves-Stevens. (Star Trek: The Official Starships Collection, issue 55, p. 15)
The first draft script of ENT: "Strange New World" established that the name "Vulcan" was a non-indigenous name for the planet, having been invented by Humans, and that the Vulcans called it something else, though precisely what wasn't revealed in the script.
Vulcan was mentioned in the final draft script of ENT: "Detained" but not in that episode's final edit. In the script, T'Pol referred to herself as a citizen of the planet, as part of some ultimately omitted dialogue between herself and Colonel Grat. Vulcan was also mentioned in a deleted scene from ENT Season 3 offering "Chosen Realm", in which T'Pol told Pri'Nam D'Jamat and two other Triannons about the planet's violent past. (ENT Season 3 DVD & Blu-ray special features)
Production illustrator John Eaves was generally impressed with how Vulcan was portrayed on Star Trek: Enterprise. "The show did do a lot at defining Vulcan," he remarked, "and it was disturbingly shaky when the series started but was hitting some level and familiar ground by season 4 [....] I loved that the show spent so much time with defining Vulcan in so many ways." 
Accounting for the decision to show Vulcan in the fourth season of Enterprise, Executive Producer Manny Coto noted, "If you really look at the Star Trek universe we've spent very little time there." (Star Trek Magazine issue 118, p. 22)
In the final draft script of "Home", a city on the surface of Vulcan was described as "our first-ever look at a Vulcan metropolis. Adobe-type dwellings line the outskirts of the city... taller, spire-like modern structures dominate the center."
Much of the Vulcan vistas in Enterprise's fourth season were designed by John Eaves, who later reminisced, "This was just about the end of designing new architecture for the hot planet, but it was quite a treat to get to dive into such an awesome world of drawings and concepts." For the episode "Home", Eaves created at least three designs for the home of T'Les. The designs for the area reflected the fact that the character was intended to be a high-ranking but somewhat rebellious woman. "So her immaculate home is rural as opposed to in the high society of downtown amongst the powerful," remarked Eaves. He originally drew inspiration from the visual appearance of P'Jem, as seen in the season 2 episode "The Andorian Incident". However, alterations were made to the concept of T'Les' home as it developed through the approval process. 
Whereas Vulcan had never before appeared in two or more consecutive episodes of any Star Trek TV series, the planet appeared extensively in a Vulcan trilogy during ENT Season 4, which consisted of the episodes "The Forge", "Awakening", and "Kir'Shara". "You were now spending more time on Vulcan," commented Mike Sussman. This was only possible due to the fourth season writing staff knowing, ahead of time, how they wanted to depict the planet. "You could say, 'I'm gonna build this gigantic Vulcan set. We can't afford it for one episode, but if you amortize it over three, we can afford it,'" explained Manny Coto. ("Before Her Time: Decommissioning Enterprise, Part Two: Memorable Voyages", ENT Season 4 Blu-ray special features)
When the story for "The Forge" was first thought up, Judith and Garfield Reeves-Stevens wrote the area of Vulcan where Archer and T'Pol met Syrran as simply "somewhere off in the wild on Vulcan"; it was only later that the specific areas of the planet which are used in the story were named. (Star Trek: The Official Starships Collection, issue 55, p. 16)
Although other parts of Vulcan were named, the first shot of the planet's surface in "The Forge" was scripted to show simply an unnamed "Vulcan desert". Even then, the notion was still to feature the planet on a grand scale, with a scripted scene description of the vista instructing it was to consist of "An epic expanse of red sand... ancient ruins of enormous statues...." Later in the script, this area was differentiated from Gateway, and Vulcan was described as having a "blast-furnace desert heat". Whereas an establishing orbital shot of Vulcan is shown at the start of the episode's third act, the script did not feature that shot.
Making Vulcan an alien environment was important to the Reeves-Stevenses. "We thought it has become a little too cosy. People had forgotten that Vulcan was an alien world," Garfield Reeves-Stevens explained. "They didn't really know much about it so we were excited because we wanted to bring the feeling back that it wasn't something familiar." (Star Trek: The Official Starships Collection, issue 55, p. 16) Added Judith Reeves-Stevens, "We were so thrilled that it was ours that we were able to do it in because [...] now, we were able to show one of the worlds, and that world became a character, and we were about to become involved with Vulcan and to remind everybody again that it is an alien world." ("The Forge" audio commentary, ENT Season 4 Blu-ray)
The episode "Home" and the Vulcan trilogy were the first live-action productions to show a city on Vulcan (coming even before the digital view of a Vulcan city in the remastered "Amok Time"). Views of the city that appears in "The Forge" (which was intended to be ShiKahr, the same city as had appeared in TAS: "Yesteryear") were designed by John Eaves and modeled in CGI by Eden FX. 
For Enterprise's Vulcan trilogy, some location footage was used, filmed in Simi Valley. ("The Forge" text commentary, ENT Season 4 DVD and Blu-ray) However, the blue skies of Earth had to be digitally color-corrected to become pale pinkish hues so as to represent the skies of Vulcan. Stated Visual Effects Supervisor Dan Curry, "Because [the actors] were against a very bald sky when we shot on location it made it a little easier to do sky replacement. Sometimes that was done in the edit bay and we had done a sample of sky gradient keeping the color scheme in homage to the Vulcan scenes in the original series motion pictures, and we tried to be true to that." (Cinefantastique, Vol. 37, No. 2, pp. 36 & 37)
Statues that appear on Vulcan in the first shot from the teaser of "The Forge" were based on computer-generated views of Vulcan in the director's edition of Star Trek: The Motion Picture and the episode "Home". ("The Forge" text commentary, ENT Season 4 DVD & Blu-ray)
While writing "The Forge", Judith and Garfield Reeves-Stevens imagined there had been a nuclear war on Vulcan about two thousand years beforehand. They intended for the surface of Vulcan to be shown as featuring fields of green glass, left over from nuclear explosions detonated during the war. (Star Trek: The Official Starships Collection, issue 55, p. 15) However, this concept was disallowed, which disappointed Judith Reeves-Stevens. ("The Forge" audio commentary, ENT Season 4 Blu-ray)
In the script of "Kir'Shara", the first view of Vulcan's surface in that episode was described thus; "A network of ravines and canyons stretches across the desert... it looks as if the planet's crust has shattered."
Denise Okuda found orbital views of Vulcan in the trilogy were "so great" and "spectacular," an opinion Judith Reeves-Stevens agreed with. Okuda noted, "The visual effects team did just an amazing job here." ("The Forge" audio commentary, ENT Season 4 Blu-ray)
Vulcan was also referenced once in a scene description from the final draft script of ENT: "United", remarking that no-one on the planet would believe that a particular moment involving a handshake between an Andorian and a Tellarite was even possible.
Although Spock tells Uhura that "Vulcan has no moon" in TOS: "The Man Trap" – a phrase that is repeated exactly in the script of the 1973 episode "Yesteryear" – a moon-like body was portrayed in close orbit of Vulcan in "Yesteryear". This was because it was typical for the artists of the animated series to never refer back to the script or descriptions, once past the storyboard process. Even though Gene Roddenberry and D.C. Fontana noted "NO MOON!" on a preliminary sketch of the planet when the drawing was submitted to them for approval, this was also ignored. By 1974, several people had inquired as to what the orb was intended to be and, in reply, Roddenberry and Fontana had had to refer to it as a sister planet. (Babel #5; Enterprise Incidents, number 11, p. 27)
Similarly, each of the two matte paintings in the theatrical edit of Star Trek: The Motion Picture depicted two large orbs in the Vulcan sky. This was "corrected" in the director's edition DVD release of The Motion Picture, with the removal of these worlds. David Morton, Foundation Imaging's Vulcan landscaper, commented, "Vulcan has no moon, and there were all these planets floating around it in the original release. These new Vulcan shots were done mainly to match better with the other films." (Star Trek Monthly issue 86, p. 53) Despite some fan speculation that the change to Vulcan's sky was made so that the film would fit the reference in "The Man Trap", this was not the case, according to Michael Matessino (who served as restoration supervisor for the director's cut). By way of explanation, he stated, "We eliminated things that you might not associate with a far-off monastic temple. We did not take our directions from a simple line of dialog. Vulcan in and of itself should be interesting without cluttering the sky. Besides, it was obvious that the sun was out in that scene. The change keeps things in the spirit of where we are going. It's not about what's up in the sky, it's about what's happening with Spock." (Star Trek: Communicator issue 136, p. 27)
Two big bodies, in a view matching the orbs in the original cut of The Motion Picture, were also incorporated into a concept painting of Vulcan's Mount Seleya and a Klingon Bird-of-Prey, created for Star Trek III: The Search for Spock. (The Art of Star Trek, p. 225)
In J.J. Abrams' Star Trek movie from 2009, an icy planet called "Delta Vega" is located so close to the Vulcan of an alternate timeline that Spock was easily able to witness his home planet's destruction from its surface. Whether Delta Vega was intended to be a reference to any possible moon or sister planet of Vulcan has not been clarified.
Several sources – such as the officially-licensed reference works The Worlds of the Federation (p. 18) and Star Trek: Star Charts (p. 58) – offer the explanation that the sister planet was named T'Khut. This name was coined (spelled "T'Kuht") by fanzine writer and artist Gordon Carleton in 1975 (upon which, he stated that T'Kuht was "the Vulcan name" for the sister planet). Carleton was influenced by D.C. Fontana's earlier postulation that Vulcan was part of a twin system. 
According to Gene Roddenberry, James Blish and multiple other background sources, the Vulcan system was the star 40 Eridani A. One official source that suggested this proposal was the 1980 reference work Star Trek Maps (pp. 25-26). An alternative possibility, included in the equally official Star Trek Spaceflight Chronology (first published in 1979), was that Vulcan's sun was Epsilon Eridani. Roddenberry favored 40 Eridani, due to the comparative ages of the two systems. In a letter printed in Sky and Telescope magazine in July 1991, Roddenberry wrote, "Based on the history of life on Earth, life on any planet around Epsilon Eridani would not have had time to evolve beyond the level of bacteria. On the other hand, an intelligent civilization could have evolved over the aeons on a planet circling 40 Eridani. So the latter is the more likely Vulcan sun." He also made the presumption that the planet orbits the primary star.  This association was continued in the books The Worlds of the Federation (p. 18) and Star Trek: Star Charts (p. 58). Both sources cite Vulcan as the second planet in the system, which Star Charts (pp. 19 & 45) places in Sector 005 in the Beta Quadrant.
In notes that costume designer Robert Fletcher wrote about the aliens in Star Trek: The Motion Picture, he proceeded from an hypothesis that Vulcan was "a ruby planet," which he gave as evidence for the presence of "the red-booted giant figure" as well as ruby jewelry in the film's Vulcan scene. (The Making of Star Trek: The Motion Picture, p. 133) Fletcher based the Vulcan clothing in Star Trek III on a similar concept related to the planet. "The concept I generated," he said, "was that Vulcan is a planet of precious minerals." (The Making of the Trek Films, 3rd ed., p. 51)
According to Michael Okuda in the book Ships of the Line (p. 22), the planet was devastated during the Time of the Awakening. The ShirKahr highlands were once green with meadows and soaring coniferous trees. During the Time of the Awakening, the highlands were destroyed by nuclear warfare, and the meadows changed into deserts. This process of destruction was repeated all over the planet, resulting in global climate change. Okuda detailed similar accounts of nuclear devastation in the text commentary for ENT: "The Forge" and in the book Star Trek: The Original Series 365 (p. 176).
Star Trek: Star Charts (pp. 44-45 & 52) details more supposition about the planet, from a production staffer (in that case, Geoffrey Mandel). The book states that, in 2378, the planet was alternatively referred to as both Vulcanis and Vulcan. The book also posits that Vulcan had been ruled by the Confederacy of Surak since 370 AD, it had two capital cities – Vulcana Regar and ShirKahr – and there were 4.9 billion people living on the planet. Two thousand years before, in the 4th century, Vulcan was a destination on the Debrune trade routes. In the mid-22nd century, Vulcan was the hub world on the Vulcan trading routes. It traded with Altair, Arcturus, Cor Caroli, Coridan, the Deneb system, Denobula Triaxa, Kaferia, Lorillia, P'Jem, and Rigel.
The Worlds of the Federation (p. 18) gives T'Khasi as Vulcan's indigenous name and states that Terran astronomers, taking inspiration from Terran mythology, provided the planet with its name of Vulcan, which the Vulcans gracefully accepted as the planet's official Federation designation. Both The Worlds of the Federation (p. 18) and Star Trek Maps (p. 26) characterize Vulcan as having "several large port cities," with the former stating that eighty-six percent of the planet's surface is landmass. The latter source describes the planet as relatively large.
Imagining one particular part of Vulcan in his autobiographical book I Am Spock (hardback ed., pp. 244 & 245), Leonard Nimoy (writing from Spock's perspective) reported, "There lies on Vulcan a stretch of flat, barren desert known as the 'plain of thought,' which has come to symbolize ultimate accomplishment. At one end of the plain stands a millennia-old fragment of wall. At the other end, approximately one of your Earth kilometers away, rests a tall, slender obelisk." Nimoy went on to envisage that successful completion of a Vulcan ceremonial test in this area – involving crossing between the wall and obelisk, then back again – results in the traveler being awarded "the right to wear the symbol of Kolinahr."
In Gene Roddenberry's novelization of The Motion Picture, he indicated that nine Vulcan seasons were equal to 2.8 Earth years. This would make Vulcan's year 456 ± 33 Earth days long. The same novelization also places the narrative's scenes of Vulcan as being in Gol. Despite specifying that Vulcan had multiple suns, the book makes no reference to any moons or additional planets in the Vulcan system.
Neither does the novelization of "Yesteryear" (which was first published in 1974) make any mention of other planets or planetoids in the Vulcan system (stating merely that "Vulcan had no moon"), even though the first edition of the anthology in which it was originally published (Star Trek Log 1) has a front cover featuring a shot of the large orb in Vulcan's sky from the aforementioned episode. It was in the 1975 fanzine Warp Speed 8 (in the Landing Party Six Writer's Guide) that Gordon Carleton first proposed the existence of Vulcan's sister planet. Later, officially-licensed Star Trek novels continued this trend, including the 1984 novel The Vulcan Academy Murders by Jean Lorrah, Diane Duane's 1988 novel Spock's World, A.C. Crispin's 1994 novel Sarek (as "T'Rukh", with a comment that this was merely another of the planet's names), and Michael Jan Friedman's 1999 novel New Worlds, New Civilizations. The latter of these features another front cover on which the sister planet appears, as does The Vulcan Academy Murders.
Prior to Gene Roddenberry's 1991 announcement that the planet Vulcan was in 40 Eridani, the suggestion was proposed in not only 1980's Star Trek Maps but also in 1968's Star Trek 2, by James Blish.