Cardassian ATR-4107
The Cardassian ATR-4107 was an incredibly advanced unmanned Cardassian prototype self-guided tactical missile designed in 2369. ()

Specifications

The ATR-4107 was a completely adaptable, evasive, warp-capable vessel, capable of reaching velocities of up to at least warp 9, and carrying 1,000 kilograms of matter and 1,000 kilograms of antimatter – enough to destroy a small moon. The missile was also armed with its own defensive weaponry, including disruptors, quantum torpedoes, a thoron shock emitter, and a plasma wave. It had its own shields as well.

On board was a sophisticated computer system that could predict and counter hostile actions by individuals and ships. It used its sensors to detect lifeforms on other ships, evaluate defensive and offensive capabilities, and recognize other ships. It had life support and an operational space for a maintenance crew with several consoles. It also had DNA scanners in order to verify the identities of persons inside. The computer system responded to voice commands. ()

History
In late 2370, around stardate 46437.5, the Cardassians designed and deployed one of these missiles to destroy a Maquis munitions base on the planetoid Alpha 441 in the Demilitarized Zone. Although the Maquis used every available weapon to attempt to counter the missile, it proved unstoppable due to the combined benefits of its strong defenses and its advanced computer. The missile failed to detonate upon reaching its target, though – the Cardassians had used an old-fashioned kinetic detonator in the design, which malfunctioned, and the missile simply drifted into orbit around the planetoid instead of destroying it.

Maquis member B'Elanna Torres used this opportunity to board the weapon and spent nearly a month reprogramming its computer and upgrading its systems, eventually nicknaming it Dreadnought. She completely reprogrammed the computer to work for the Maquis, and changed its vocal subroutines so that the computer sounded like her, as she claimed that she had gotten sick of listening to the "ugly" male Cardassian computer voice.

Once she completed refitting and upgrading Dreadnought, she sent it, without authorization from Chakotay, her commander, to attack the Cardassian fuel station on Aschelan V. The missile's evasive attack route took it through the Badlands, where it inexplicably disappeared. It was assumed that the missile was destroyed in a plasma storm. 

It was not realized until nearly two years later that Dreadnought had been abducted by the  and whisked away to the Delta Quadrant by the advanced entity. The missile drifted on a rough course back towards the Alpha Quadrant, but it had suffered some damage to its computer and sensor systems that altered the way it perceived potential targets. It attacked and destroyed an unarmed transport before locking on to the nearby planet of Rakosa V, an inhabited world, which its sensors had confused with its original target.

Fortunately, the  was nearby, having also been abducted by the Caretaker the year before, and B'Elanna Torres was on board. She used her familiarity with the missile's systems to board the weapon and instruct it to deactivate. Torres then returned to Voyager, and the crew made plans to dismantle the weapon and salvage its parts.

Dreadnoughts computer had other plans, though. Back in the Alpha Quadrant, Torres had programmed the computer with defenses for thirty-nine different potential security breaches, including the possibility that Torres herself was coerced into cooperating with either the Cardassians or the Federation and attempting to stop the missile from attacking its target. The computer accused Torres of collaborating with the Cardassians.

As the missile approached Rakosa V, it was confronted by a small fleet of fifteen defensive fighters; even with the Rakosans receiving support from Voyager, they were vastly outgunned and quickly forced to withdraw. Torres used the diversion to activate the latent Cardassian computer programming, which attempted to retake control of the missile. Torres' Maquis program initiated countermeasures, attempting to wipe out the attacking "virus". Torres then took the opportunity to work her way into the missile's warp core, where she used her phaser to burn her way through the reactor core's shielding.

As Torres was attempting to destroy the magnesium casing on the warp core, Captain Janeway ordered her crew to abandon Voyager and prepared to activate the ship's auto-destruct sequence, ready to sacrifice her ship and herself to save the planet. Torres succeeded in destabilizing the core, and Janeway canceled the sequence just a minute before the explosion. Torres herself was beamed out at the last second, as the missile exploded in orbit of Rakosa. ()

Appendices

Background information 
In the first draft script of "Dreadnought" (which had the working title "Original Sin"), the name of this weapon was the "Van'ra", which was said to be translated as "Death's Angel", and its exterior was described thus; "a large, sleek, slender ship, almost as long as Voyager, but not nearly as wide or tall. It's distinctly Cardassian in design, built like a mobile fortress, with disruptor turrets and torpedo launchers all around it. Not meant to have a crew, it has no portholes of any kind. It looks quite menacing, yet has a certain grace in its design – a fishlike, stingray fluidness that suggests its elusive nature." In the final draft script of "Dreadnought", this description was changed to, "It's a sleek, somehow sinister-looking missile, with large engines, and covered with all manner of weaponry."

The Dreadnought missile studio model was designed by Rick Sternbach. ()

The missile's voice was provided by B'Elanna Torres actress Roxann Dawson. "Dreadnought"'s first draft script stated, "There is an odd, almost inhuman undercurrent to its vocal tones, which are filtered through unseen speakers. Although it is a reproduction of Torres' voice, there is enough in reverb and delivery to distinguish it from the original." The final draft of the script changed this to simply say, "The computer speaks in Torres' voice, with a slightly mechanized tone, and no emotional inflection whatsoever."

The missile interior was designed by Richard James. An extreme number of fluorescent lights were built into the set, so that Director LeVar Burton could film there with a hand-held Steadicam without being encumbered by equipment in the way, allowing the production crew to film more quickly on the set. ()

Apocrypha 
In Star Trek: Armada II, the Dreadnought missile appeared as a Cardassian weapon. Upon impact with its target, it created a spatial rift that destroyed any ship or station within its radius. If destroyed by enemy fire, however, it would explode normally with no damage to nearby structures.

In Star Trek Online, the Dreadnought is mentioned by name in the information revealed with the completion of the Temporal reputation line. It's revealed that Na'kuhl agents beamed aboard the weapon and attempted to sabotage it in order to attack Voyager, but was stopped by Temporal Agents, despite the weapon itself attacking the agent due to being a Cardassian. It's suggested that this is why the weapon went out of control.

External links

cs:Cardassijská ATR-4107
de:ATR-4107
ATR-4107
Explosive weapons