Astromech Droids, also known as Astro Droids, are droids which serve as automated mechanics and are used for various other utilities, including navigation, control of various computer systems and even functioning as starfighter co-pilots.
R2-D2, widely considered the most famous of the R-series Astromech Droids.
While the term 'Astromech' was originally used to refer to utility droids during the Jedi civil war, it was the company 'Industrial Automaton' who officially created the Astromech Droids, along with the GNK Power Droid and the 2-1B Surgical Droid. Astromech Droids are typically built with a wide variety of tools attached to concealed appendages within their casing. Unable to speak, Astromech Droids typically communicate either through displaying text on an attached computer screen, or through auditory binary, which are primarily heard as a series of high-pitched beeps, clicks and whistles. Although they are usually built and programmed for maintenance and other duties, Astromech Droids have displayed emotion and personalities which may be developed over time. For example, R2-D2, has regularly displayed excitement, annoyance, a sense of humour and intense loyalty over his many decades of service, while BB-8 has displayed a childlike personality
BB-8; a BB-series Astromech.