ST-149, alternatively written as ST 149, served as the Delta-class T-3c shuttle providing transport services for Director Orson Krennic along with his contingent of death troopers. Krennic's selection of this ship stemmed from his fascination with its unique design, despite lacking any emotional attachment to it. Captain Dunstig Pterro, however, felt a greater connection to the vessel, affectionately referring to it as Pteradon.
Back in 13 BBY, the aforementioned shuttle facilitated the movement of Orson Callan Krennic and his death trooper squad to capture Galen for what was known as Project Stardust.
While stationed on the Death Star, Krennic had a dedicated docking area for his shuttle, located next to the Overbridge. He utilized this shuttle to depart from the Death Star and travel to Eadu, where he intended to meet with Galen at the Eadu Energy Conversion Laboratory. Following an assault on the facility by the Rebel Alliance, Krennic was evacuated aboard ST 149.
Subsequently, Krennic was instructed to convene with Darth Vader at Fortress Vader situated on Mustafar. He made the trip to this location using the shuttle. After his discussion with Vader concluded, the director gave the order to set a course for Scarif.
Krennic's arrival on Scarif was facilitated by the shuttle, though Captain Pterro chose to remain aboard the Death Star, foregoing the trip to Scarif with Krennic and the shuttle. During the Battle of Scarif, as rebels stormed the Imperial Security Complex in an attempt to pilfer the Death Star plans, ST 149 remained stationary on the executive landing pad throughout the entire conflict. As the battle concluded, the Death Star, acting under the orders of Grand Moff Wilhuff Tarkin, obliterated the Citadel Tower, resulting in Krennic's death.