The International Space Station today has a real-life R2-D2. Well not exactly but a near equivalent of the concept at least. Called Robonaut 2, this little robot was designed to flip switches and conduct simple experiments that would then allow our astronauts to concentrate on more complicated activities. NASA hopes that in future editions of the Robonaut, it will be able to walk in space and conduct more complicated activities on its own. This would reduce the number of risky spacewalks that our astronauts currently undertake.
Then there is C-3PO, whose single objective was to act as a universal translator in the Star Wars franchise. While no such robot currently exists, there are precursors already. Take the Kirobo for instance. This child like robot developed by a Japanese university in association with Toyota recently had a long chat with Koichi Wakata in the ISS. It is designed to be an interactive robot, mostly for lonely folks. It augers well not just for astronauts but also senior citizens.
In Star Wars, the Jedi train using synchronized robots that are aware of not just their surroundings but also each other. In real life, NASA used a set of droids that could conduct synchronized flight, aware of each other and thus capable of avoiding one another. The notion is to use these synchronized droids in complicated space missions and eventually to have intelligent satellites that can avoid each other.
Likewise, there are several less obvious usages of ideas explored by Star Wars. Take for instance the Solar Panels. The TIE fighter of the Empire had an entire exterior made from solar panels. This is what NASA does with all its Mars probes at present. Plus, the International Space Station itself has several solar panels on its surface to augment its power requirements.
Next up are lasers. Lasers were the preferred weapon for combat in Star Wars and NASA is currently testing lasers as a means of super high speed communications in space. The latest Lunar Reconnaissance Orbiter probe actually held the first live testing of the laser systems as pictures were transmitted to and from the orbiter in real time. Lasers as communication tool can transfer massive amounts of data as opposed to radio waves and signals.