In use since at least 2478, the terrans of the Koprulu Sector built Explorer-class science vessels to conduct a wide range of research and development projects, stationed at points throughout the Koprulu Sector and beyond to study anomalous phenomena and early on, search for alien life. In addition, the Confederacy's Epsilon Squadron used science vessels extensively for border surveillance and study.
When contact with the protoss and zerg devolved into open warfare, many Explorers were requisitioned by military authorities to provide electronic warfare and support for forces in the field, along with aiding the research and development of new weapons and technologies.
Science vessel commanders and crewmen required a PEB (Preferred Experience Base) of any hard science and electronic warfare.
The primary function of the science vessel was the employment of its detection abilities. Other functions, with the appropriate equipment, included the creation of a defensive matrix, the generation of a short ranged EMP (alternatively this could be detonated at a distance via the launching of a warhead) and irradiation of a target via a high-energy stream of radioactive particles, saturating it with damaging energy. For increased energy output, a titan reactor could be installed. All science vessels possessed Ghost Program files, stored in a secure room at the bottom of the vessel, in case a ghost required "repair" (what amounted to medical aid in the program).
After the Brood War, the Terran Dominion substituted the Raven for the expensive science vessel in the battlefield support role. During the Second Great War, Raynor's Raiders were able to develop a new class of science vessel. This model can carry out hull repairs through nano-technology and retains the irradiation function from its predecessor.
The science vessel is a terran mobile detector. Like most other spell casters, science vessels have no direct form of attack. Air units such as scourge, wraiths or scouts are ideal for dealing with the slower science vessel.
Reduces the hit points of biological units near the targeted unit (and the targeted unit itself if it is biological) by 250 over 30 seconds. Mechanical units are immune, but biological units passing near an irradiated mechanical unit will still be affected.
The science vessel was replaced by the Raven in multiplayer.
They may be unlocked in campaign mode for 20 protoss research points.
The science vessel has limited offensive capability, and is geared for supporting mechanical units with its repair ability. In contrast, the Raven is less durable but its abilities are more versatile when directly attacking enemy units.
Irradiates a single target, causing damage over time to target and any nearby units for 30 seconds. Irradiate does not damage mechanical units, but nearby biological units will take damage from an Irradiated mechanical unit.
The science vessel's voice was provided by Harry Shearer, known also for his voice acting numerous characters on The Simpsons including Mr. Burns. One of the "order confirmed" quote of the science vessel is "excellent," the first syllable drawn out a bit, similarly to Mr. Burns.
In-game, science vessels are about the size of a Behemoth-class battlecruiser or smaller. However, in the cinematics, the science vessel is a gigantic starship.
Science vessel commanders are usually ranked "Major" (an army rank rather than a navy rank). This can only be seen if the science vessel is affected by Lockdown or Stasis.
In the Wings of Liberty campaign, the StarCraft II version of the science vessel also has two unused abilities that essentially make it the terran version of the protossarbiter: Cloaking Field and Transwarp. The science vessel was also upgradable with the Plasma Weaponry upgrade from the Hyperion's armory, which gave it a weapon. Transwarp remains as only a button within the editor, but Cloaking Field is a complete ability. Plasma Weaponry remains only as an upgrade, as no actual weapon was made for it.