"This is the Empirical, master, Lord Vader's top-secret mobile laboratory." ―PROXY, to Galen Marek[src]
The ISS Empirical was a mobile research laboratory, a modified cruiser that belonged to Dark Lord of the Sith Darth Vader. Rumored to be one of many such vessels in Vader's fleet, the Empirical housed the Dark Lord's experiments on prisoners and studies conducted on unique alien species. Top-secret, moving only between lifeless star systems in the Outer Rim Territories and escaping even the eyes of Emperor Palpatine's spy network, the vessel was crewed by a platoon of Imperial soldiers personally selected by Vader, who monitored the test subjects and eliminated those that escaped confinement before they could get off the ship.
In 3 BBY, Emperor Palpatine confronted Vader on Vader's flagship, the Executor, over his taking of an apprentice, Galen Marek. To prove his loyalty, Vader impaled Marek with his lightsaber and cast him out into the vacuum of space. Secretly, however, a droid retrieved Marek's unconscious body and took him to the Empirical. Vader's medical droids spent six months rebuilding Marek, as the apprentice lay unconscious. To the rest of the ship, Marek was viewed as another of Vader's experiments, and he was designated "Subject Zeta" and "Subject 1138." Vader had Marek's droid PROXY and ship, the Rogue Shadow, delivered to the vessel as well, and to aid in his mission Marek was given a new lightsaber. His pilot, Juno Eclipse, had meanwhile been arrested for treason; after some time, she too was transported to the Empirical, where she feared she would become part of a Sith experiment.
When Marek at last awoke after six months, by which time the Empirical had moved into the Dominus system, he was greeted by Vader, transmitting his image through PROXY. Vader told Marek that Palpatine believed him to be dead, then assigned him the task of building an army to oppose Palpatine. The Dark Lord threatened to activate the Empirical's self-destruct sequence if Marek did not comply, but Marek gave in. PROXY, too, had been given instructions, and when Vader cut his transmission, the droid set about fulfilling his orders to help Marek escape, and to eliminate all evidence of Marek's survival, including the vessel and its crew. Marek broke out of his chamber, and his room began to flood with poison gas; he turned it off, but a squad was sent to monitor the situation. An alert was sent through the ship warning that Vader's subject had escaped. Having heard from PROXY that Eclipse was aboard, Marek went for her first, slaughtering his way through the crew, all of whom had orders to kill him. PROXY, meanwhile, accessed the vessel's main computer, and, determining it was the quickest way to eliminate everyone aboard, set the ship on a course into the system's star. The crew of the ship was alarmed when their navigation began malfunctioning, and a series of announcements apprised the rest of the vessel of the deteriorating situation. An evacuation was ordered, but PROXY continued with his work, disabling security systems and, to make sure no crew members made it out, ejecting the ship's escape pods.
Marek made it to Eclipse's detention cell to find several of the ship's officers with her, behind a force field. After killing the stormtroopers outside it, Marek brought down the field, eliminated the rest of the crew in the vicinity, and rescued Eclipse from her restraints. He helped Eclipse get to the Rogue Shadow, which PROXY had gotten ready, and they evacuated the research vessel. The Empirical, meanwhile, continued on its doomed course, exploding as it fell into the system's sun.