BB-8 is the cutest character in The Force Awakens. Like the more famous R2-D2, he’s an astromech droid who helps fly and maintain an X-wing Starfighter.

How does BB-8 work? This article won’t describe the science in too much depth (this Tech Crunch post has details on the physics). Instead, I’ll give simple explanations and discuss what that tells us about how a real BB-8 would work in the fictional Star Wars universe.

Floating head

While R2 units like R2-D2 are cylinders with legs, BB-8 is a dome on top of a sphere. What stops his head from falling off?

At least that’s how the BB-8 toy works. The attachment mechanism is described in a 2014 patent application by Sphero, the company that produces a remote-controlled droid. Like Sphero’s other robotic balls, the BB-8 toy uses a gyroscope to work out which way is up, and accelerometers to determine when it’s moving. Measurements from these sensors are used to make continuous adjustments so that the robot keeps its head.

Read the article “How BB-8 Works in Star Wars: The Force Awakens” on forbes.com.