The Bandit asteroid ship was a type of spacecraft disguised as an asteroid, used by pirates for illegal mining operations in the 23rd century.
Background
The vessel was designed for use in System C-71 in the Ferrous-Asteroid Belt, a region rich in iron deposits where mining had been outlawed. The rocky exterior of the craft was approximately 80 feet long, 40 feet tall, oblong-shaped, with two chemically-propelled engines at the back. It was armed with phasers and missiles. In order to be useful for illicit mining, either a large portion of the interior was hollow to carry cargo or it was able to tow iron asteroids. It appeared capable only of interplanetary travel.
History
Two such ships were exposed by the crew of the USS Enterprise in the year 2266. One was discovered near the Camel asteroid where no objects had appeared on the charts. During an EVA survey of its surface, a low-powered phaser shot at an outcropping panicked the bandits, who fired up their engines and shot at the Enterprise. The starship returned fire and destroyed the craft.
A second asteroid ship was discovered by using a radi-lyzer x-ray scanner to scan the interior of nearby asteroids. The exposed vessel attempted the ram the Enterprise, then fled. As it passed the fifth planet in the system, Kibo/Ndora, the bandits fired a missile towards the surface. The starship halted pursuit and instead tracked down the missile, which yielded proof of a conspiracy to frame James T. Kirk with treason, for being in league with the leader of the bandits, Liji Bragg. (TOS comic: "The Trial of Captain Kirk")