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Official Site: LucasFilm Ltd
The Death Star is a fiction moon-sized space station and superweapon appearing in the Star Wars movies and expanded universe. It is capable of destroying a planet with a single destructive beam emitted from the large indentation on its surface. In the films, the first Death Star is featured in Star Wars Episode III: Revenge of The Sith being constructed and in Star Wars Episode IV: A New Hope which at that time is fully constructed, and a second Death Star is under construction in Star Wars Episode VI: Return of the Jedi.
Although particular details, such as the superlaser's location, shifted between different concept models during A New Hope's production, the notion of the Death Star being a large, spherical space station was consistent in all of them. The buzzing sound counting down to the Death Star firing its superlaser comes from the Flash Gordon serials. Portraying an incomplete yet powerful space station posed a problem for Industrial Light & Magic's modelmakers for Return of the Jedi. Only the front side of the 137-centimeter model was completed, and the image was flipped horizontally for the final film. Both Death Stars were depicted by a combination of complete and sectional models and matte painting.
The original Death Star first appears in A New Hope. Commanded by Grand Moff Tarkin (Peter Cushing), it is the Galactic Empire's "ultimate weapon", a space station capable of destroying a planet in a single attack. The film opens with Leia Organa (Carrie Fisher) transporting the station's schematics to the Rebel Alliance to aid them in destroying the Death Star. Tarkin orders the Death Star to destroy Leia's home world of Alderaan in an attempt to pressure her to betray the Rebels. In the film's climactic battle, Luke Skywalker (Mark Hamill) uses his power in the Force to help him destroy the station.
In Return of the Jedi, set four years later, the Empire is building a new Death Star; it is half-finished throughout the film. Emperor Palpatine (Ian McDiarmid) and Darth Vader (David Prowse/James Earl Jones) send the Rebels false information that the station's weapons systems are not operational in order to lure them into a trap, and bring Skywalker on board to tempt him over to the dark side of the Force. In the film's climax, Vader kills Palpatine on board, and is mortally wounded in the process. Skywalker escapes with Vader's body moments before the Rebels destroy the station.