One of the most striking elements of the Star Wars: The Force Awakens trailers that we’ve seen is that adorable, inventive droid, who we’ve since learned to call BB-8. Simultaneously something familiar and fresh—it looks like droids we know in some regards, but the fact that the head sits on top of a rolling ball of a body marks it as very different—there’s been a lot of discussion about the science behind this new astromech, especially once we learned it was a practical effect, not GGI, and two fans have broken it down for our convenience.
Lucasfilm hasn’t revealed exactly how they made the tricky little droid work, but two Spanish Star Wars fans, Carlos Sánchez, an engineer, and Emilio Gelardo, a designer who specializes in building all things Star Wars, think they have cracked the code, and their findings are on their website, HowBB8Works.com. Like many others curious about this subject, the two basically just poured over every article or scrap they could find. Sánchez tells Yahoo:
We found some very cool articles about it, but they were all missing something; none really explained, in-depth, the full story behind BB-8
As much as they dug, it remained a mystery, until the duo found a patent filed by Disney back in 2010 for a "magnetic spheric balancing robot drive." Patents are public, but for some reason no one paid much attention to this one, and it led Sánchez and Gelardo to posit two theories about BB-8 based on this information, one of which they know must be wrong. Their site also has a handy dandy animated rendering of each, so you can get a solid idea of how each idea would work.
The first design is actually based on the mechanics of an AT-AT foot, and has a mechanism that allows the head to move freely around the top of the spherical body on a magnet and set of ball bearings, while a four-wheeled drive system propels the body.
The second is closer in design to the patent. A drive system similar to the first controls the movement and direction of the body, while the head is attached to an arm—again, via a system of magnets and rollers that are likely used to allow the head and body to move independently from one another.
As cool as BB-8 looks in action, rolling across the rough desert ground of Jakku at high speed in the sparse bits of footage from The Force Awakens that have been revealed thus far, to see it in real life is actually even more impressive. At Star Wars Celebration a few months back, the little astromech was onstage with some of the key movers and shakers from Lucasfilm—BB-8 and R2-D2 even had a tense stand off at one point—and just how natural and fluid the droid looks is remarkable.
We don’t know a ton about BB-8, either the practical effect or the character, but it is believed that, like R2-D2, the new droid is designed to fit into the socket of an X-Wing Fighter, specifically the newer model that we’ve seen glimpses of—it makes sense the crafts would get an upgrade over the course of thirty years. It’s also been posited that BB-8 belongs to Oscar Isaac’s pilot, Poe Dameron.
Like most things related to Star Wars: The Force Awakens, we won’t know any of this for sure until the movie opens on December 18.