- "Imperial XX-23 S-thread tracker was developed by Sienar Systems to trace ships through hyperspace to destination."
The Imperial XX-23 S-thread tracker, also known as the XX-23 S-Thread Tracer, was a homing beacon developed by Sienar Fleet Systems to track ships through hyperspace to their destination. The tracker was able to be launched from the warhead launcher of a TIE Advanced v1 starfighter and was used by the Grand Inquisitor to track the Ghost. Five years later, another XX-23 was used to track the Millennium Falcon to Yavin 4, which allowed the Empire to discover the secret rebel base there.
The XX-23 S-thread tracker was a model of homing beacon used by the Galactic Empire. When the Millennium Falcon escaped from the Death Star, carrying Leia Organa and the battle station's plans to the Rebel base on Yavin 4, the Empire tracked the ship via one such device attached to the freighter's underside. On Yavin 4, Major Capin Harinar of the Alliance Intelligence and his men located the beacon, which was transmitting when they found it. In a message to General Davits Draven, Harinar noted that the device in question was fitted with a hyperwave narrow-band transceiver, and described it as an Imperial Department of Military Research custom job.
- Star Wars Rebels – "Gathering Forces" (First appearance)
- Ezra's Duel with Danger
- Star Wars: Episode IV A New Hope (First mentioned)
- Star Wars: A New Hope junior novelization (Mentioned only)
- LEGO Star Wars: The Freemaker Adventures – "The Pit and the Pinnacle" (Mentioned only)
- LEGO Star Wars: The Freemaker Adventures – "Free Fall"
- Star Wars: The Rebel Files
- Dawn of Rebellion (First identified as XX-23 S-Thread Tracer)
- TIE Fighter Owners' Workshop Manual
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