Sienar TF73

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Sienar TF73, or just Sienar or 73, was a snow-covered planet in the Outer Rim Territories' Tharin sector that was owned by Sienar Fleet Systems. One of many numbered worlds owned by the company, 73 was home to Sienar Test Facility 73. A TIE Avenger prototype was kept there and inspected by the technician Niya. In 4 BBY, Niya helped the rebel spy Cassian Andor infiltrate the facility to steal the prototype. After prepping the TIE Avenger for a test flight, she briefed the spy, who reassured her about her sacrifice.

Andor proceeded to board the TIE Avenger and try to fly it out of the facility. Difficulty with the unfamiliar controls delayed the spy, who was forced to fight off facility security before he could break out. He was pursued by two TIE/ad v1s through 73's canyons and ultimately destroyed his pursuers with falling debris and escaped offworld.

Description

Sienar TF73,^[6] also known as simply Sienar^[4] or 73,^[5] was a terrestrial^[4] planet^[5] located in an eponymous star system within an intersecting portion of the Outer Rim Territories^[1] and the Slice.^[2] Situated in the Tharin sector at the coordinates S-8 on the Standard Galactic Grid,^[1] it lay along the Triellus Trade Route^[3] between the Jabiim and Yarma systems.^[6] The world was covered with an arctic landscape that included glaciers. It featured snow-covered mountains and canyons on the land and an ocean with icebergs. The climate was frigid with winds.^[4]

History

Security breach

By the reign of the Galactic Empire, Sienar TF73 was one of many numbered worlds owned by^[5] the starship manufacturing company^[7] Sienar Fleet Systems. There, the company housed Sienar Test Facility 73, which housed many Imperial secrets and was subsequently defended by its own battalion.^[5] The facility's security operated without a fixed roster, to the dislike of some, though fear of being reassigned kept them from speaking up.^[4] As the Empire expanded its Imperial Navy,^[8] Imperial engineers seeking to improve^[9] Sienar Fleet System's^[7] TIE fighter developed^[9] the TIE Avenger prototype at the facility.^[8] The Sienar technician^[10] Niya was assigned to the prototype's upkeep.^[11] However, despite having enjoyed her job, she communicated with^[4] an anti-Imperial network secretly coordinated by the rebel agent Luthen Rael.^[12] A plan was formed by the network to steal the TIE Avenger prototype with the help of Niya.^[4]

The rebel spy Cassian Andor infiltrated Sienar Test Facility 73 in 4 BBY disguised as an Imperial test pilot. While Andor waited to meet her, Niya prepped the prototype for a test flight the next morning. She met with the spy for the first time, briefing him on the situation of the TIE Avenger, giving him the password and credentials to access the fighter, and producing a cover story for their conversation. The technician was nervous about the mission, but Andor reassured her about her sacrifice. The pair were briefly interrupted by a coworker of Niya, who gave the cover story to her colleague before the latter moved along. Niya asked Andor if it was worth it if she died that night, the spy reassuring her that her decision to help the fight against the Empire made it worth it already. After thanking him, the technician asked for a twelve-minute head start. Andor agreed and the two parted ways.^[4]

To steal a TIE

Andor soon made his way to the TIE Avenger's hangar and used Niya's credentials to open the hangar doors. He shot a droid stationed there before climbing into the prototype. Unfamiliar with the controls, the spy attempted to fly the TIE Avenger out of the hangar, only to reverse it by accident and start crashing into the walls and ceiling. The commotion sounded the station alarms, and the hangar doors closed as a complement of stormtroopers arrived to attend to the situation. The stormtroopers fired on the prototype, but Andor quickly figured out how to let loose the fighter's machine guns on them, quickly dispatching the troopers. A range trooper armed with a Smart Rocket attempted to flank and destroy the TIE Avenger, but Andor evaded the first rocket and eliminated the trooper with a special high-powered laser cannon on the prototype.^[4]

Andor blasted his way out of the hangar in the TIE Avenger, which initially slid across 73's icy surface to the edge of a canyon cliff, where it lost power. Two TIE/ad v1s,^[4] another prototype model from Sienar Fleet Systems,^[7] were deployed to deal with the rebel spy. While the Avenger prototype was restoring power to its systems, the TIE Advanced fighters each fired a torpedo. However, Andor was able to take off and evade the missiles before descending into the canyon. The two TIE Advanced v1s pursued and fired on the TIE Avenger as the rebel spy struggled to maneuver it. The chase made its way between some glaciers toward a glacial tunnel. Andor fired four torpedoes at the glacier, causing the tunnel to collapse as he flew through with his pursuers. The two TIE Advanced v1s were crushed by the collapse, allowing Andor to escape Sienar TF73 in the stolen TIE Avenger to return to his contact on^[4] the moon^[7] Yavin 4.^[13]

Locations

On 73 was Sienar Test Facility 73, which was ran by Sienar Fleet Systems and housed Imperial secrets^[5] like the TIE Avenger prototype. An illuminated open road ran from the facility to another lit location on the planet.^[4]

Behind the scenes

Sienar TF73 first appeared as just "Sienar" in "One Year Later," the first episode of the second season of the live-action television series Star Wars: Andor,^[4] which aired on Disney+ on April 22, 2025.^[14] It was initially teased in the first trailer for the season, posted on the official Star Wars YouTube channel on February 24 of that year.^[15] The world was identified as "73" in a StarWars.com Databank entry about the Sienar Test Facility 73 located there, which was published by the day after the release of "One Year Later."^[5] It was identified in an October 13, 2025 update^[16] to the Star Wars Galaxy Map on StarWars.com,^[1] authored by Jason Fry.^[16]

The hangar scenes on 73 were filmed at Pinewood Studios.^[17] Industrial Light & Magic (ILM) used visual effects to model the planet's landscape and the action sequences on it. It showed some of the processes of its visual effects in a video presenting its work for the consideration of an Emmy nomination.^[18] Indeed, ILM earned a nomination for "Special Visual Effects in a Season or a Movie," one of fourteen nominations the season received,^[19] and the company went on to win the award at the 77th Primetime Creative Arts Emmy Awards.^[20]

Appearances

• Star Wars: Andor — "One Year Later" (First appearance)
• Star Wars: Andor — "Welcome to the Rebellion" (Mentioned only)

Sources

Notes and references