R2-D2:

          R2-D2 is an R2 unit designed to withstand the vacuum of space and to interface with computer systems. He can monitor maps and flight perfermance as well as store hyperspace data. He can also pinpoint and repair errors, computer damage and faults in the system coding. He is able to repair hundreds of styles of crafts.
          Artoo's speech can be heard only as beeps and whistles. He can understand most forms of speech but his communications must be translated by a computer or protocol droid, usually C-3PO. C-3PO and R2-D2 have formed a mutual bond. R2-D2's domed head holds a radar eye, heat and motion detectors, electromagnetic-field sensors, infrared receptors and a holographic recorder and projector. In his lower body Artoo holds a circular saw, electric shock prod, flame-retardant foam dispenser, grasping claw, laser welder, a storage/retrieval jack for computer linkup and much more.
          Not much is known about Artoo's past but we do know that one master, a smuggler, abandoned Artoo and Threepio on the planet of Indigo. On that planet they were taken in by Thall Joben, a speeder racer. Some other known masters include the Royal House of Alderaan, the Pitareeze family and Captain Antilles. At one point, Princess Leia placed vital information about the Empire's super-weapon the Death Star in Artoo's databank. She sent Arto to Tatooine to search for Obi-Wan Kenobi. When obi-Wan, along with Luke Skywalker and Threepio, hired transport to Alderaan they encountered the Death Star and a just blown away Alderaan. Soon Artoo and company succeeded in rescuing the Princess and delivering the information safely into the Rebellion's hands. The Revellion was successful in finding a weakness in the Death Star and Luke Skywalker with R2-D2 by his side succeeded in destroying it.
          Later R2-D2 accompanied Luke on several adventures including his training by Jedi Master Yoda on the planet Dagobah, aiding the escape of Leia, Chewbacca, Threepio and Lando Calrissian on Cloud City and rescuing Han Solo from the clutches of Jabba the Hutt.
          Years later Artoo noticed that some of his files had been replaced during the emergence of the Emperor Palpatine clone. He later figured out that Luke was transmitting codes that later enabled the New Republic to shut down Palpatine's World Devastators which were ravaging Mon Calamari. When a new X-Wing design was introduced with integrated nava computers instead of astromech droids, Artoo was outraged. Artoo, along with Threepio and Cole Fardreamer, later uncovered a dangerous scheme by Dark Jedi Kueller. Kueller had planned to remote detonate several explosions in the X-Wing on several planets in the New Republic but Artoo had traveled to Telti where he confronted a gladiator-droid group Red Terror and deactivated the remote detonators sparing the New Republic destruction.
          Artoo has remained loyal to Luke Skywalker and was with him when he started the Jedi Academy.