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 the scourge, wraith, or scout 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.