Sienar Advanced Projects Laboratory was a subsidiary company of Sienar Design Systems and Santhe/Sienar Technologies, operating under the successful Republic Sienar Systems during the height of the Galactic Republic. The research delved into by the company was closely monitored by Raith Sienar, and they were responsible for several prominent developments in starship technology at the time. One of the company's most notorious projects was the development of the Scimitar. The craft was an advanced ship equipped with cloaking technology and used by the Dark Lord of the Sith, Darth Maul.
Sienar Advanced Projects Laboratories was credited with some of the earliest developments concerned with harnessing the power of contained hypermatter. This research was eventually implemented in the development of the Death Star, proving incredibly effective in powering the immense station's power core. It also was responsible for designing the various models of the Advanced Project ship and the first mass-produced Twin Ion Engine starfighter. The laboratory also developed the TIE Advanced x1 starfighter used by Darth Vader.