Tierfon, a planet situated within the Expansion Region, served as the location of a launch base for the Rebel Alliance. This outpost accommodated at least one hundred rebel pilots. Functioning as their headquarters, the Tierfon Yellow Aces squadron utilized the base for numerous missions and to defend the outpost. The Galactic Empire took notice of Tierfon's sector due to this rebel activity, and the increased Imperial patrol presence eventually forced the rebels to abandon the launch base and disband the Yellow Aces.
Tierfon was a planet of the terrestrial type, found in a sector of the Expansion Region.
By the time 2 BBY arrived, Tierfon had evolved into a starfighter launch base outpost for an organized rebellion opposing the Galactic Empire, secretly under the direction of Senator Mon Mothma. A map sent to Mothma in 2 BBY, before she officialized the rebellion as the Rebel Alliance that same year, identified the base as a level five (or higher) starfighter hub among rebel safe worlds, fighter hubs, operational headquarters, shadow planets, and deep space caches. Later, Archivist Hendri Underholt incorporated this map into The Rebel Files, a collection of non-electronic documents.
The Tierfon launch base housed a minimum of one hundred rebel pilots and served as the central base for the Tierfon Yellow Aces, a small squadron of T-65B X-wing starfighters responsible for defending the outpost. From Tierfon, the Yellow Aces undertook many missions in the Mid Rim, but their actions drew the attention of the Empire to the sector. The growing presence of Imperial forces and their pilots led to increased patrols, which in turn put more pressure on the Tierfon rebels, causing them to abandon and scuttle the launch base before 1 BBY. Consequently, the Tierfon Yellow Aces were disbanded, and its members were reassigned to other rebel bases.
The Tierfon Yellow Aces had their headquarters on Tierfon. This X-wing squadron was once led by Captain Dosmit Ræh and included rebel pilots such as Robich Duggsin, Vangos Grek, and wingmates Jek Porkins and Lieutenant Zal Dinnes. Dinnes was a human native of Tierfon, and Grek commanded some of the Yellow Ace's raids while stationed on Tierfon. After the squadron's disbandment, Dinnes, Duggsin, Grek, and Porkins were among those reassigned to the rebel base on the moon Yavin 4. Yendor Brethen, a Twi'lek Y-wing starfighter pilot, was also one of the rebel pilots on Tierfon.
The name "Tierfon" entered official Star Wars canon through references to the Tierfon Yellow Aces in Rey's Survival Guide and Star Wars: The Force Awakens: The Visual Dictionary, two books released on December 18, 2015, by Jason Fry and Hidalgo, respectively. The planet itself was initially described in Pablo Hidalgo's 2016 reference book, Star Wars: Rogue One: The Ultimate Visual Guide.
The planet Tierfon has its origins in the Star Wars Legends continuity, where it was first mentioned in The Star Wars Sourcebook by West End Games. Bill Slavicsek and Curtis Smith authored the book for use with Star Wars: The Roleplaying Game, and it was published in 1987. Tierfon later made a complete appearance in Vision of the Future, the second book in Timothy Zahn's Star Wars: The Hand of Thrawn Duology (1998), which identified it as the unnamed location in Specter of the Past, the first book of the series (1997).
The 2017 canon reference book Star Wars: The Rebel Files, written by Daniel Wallace, places Tierfon in the Expansion Region, although a map in the book mistakenly swaps the labels for that region and the Mid Rim Territories. The "Helmets" section of De Agostini's Star Wars Helmet Collection magazine, issue seventy-nine, which was published on January 9 of 2019, instead placed Tierfon in the Mid Rim. This article assumes the placement of Star Wars: The Rebel Files is accurate, aligning with the Star Wars Legends placement of the Tierfon system, and therefore Tierfon, by the StarWars.com Online Companion for the 2009 reference book The Essential Atlas.