In-universe, how is BB-8's head adhered to his body?

Animated gif of BB-8 rolling past random garbage on Jakku.

  • 6
    Haven't seen any material on it, but as an engineering problem, I'd approach it this way. Gyroscopes inside the ball keep an orientation against which to rotate the body for motion. Those same gyroscopes could keep an arrangement of magnets near the 'top' that suspend the 'head'. So ..magnets. Commented Dec 14, 2015 at 19:23
  • 3
    – user31178
    Commented Dec 14, 2015 at 19:24
  • 3
    Duct Tape!
    – Xantec
    Commented Dec 15, 2015 at 0:03
  • 1
    The design of BB8 is so perfect. Really captured the feel of droids in the classic trilogy; has an R2D2-ness about it while also being quite fresh and different. ❤️
    – zipquincy
    Commented Dec 15, 2015 at 0:11
  • 4
    Magnets: xkcd.com/413
    – b_jonas
    Commented Dec 16, 2015 at 12:51

3 Answers 3


To add (and hopefully canonically replace?) Praxis's excellent answer: BB-8's head is held via magnetism using magnetic casters.

From TFA Visual Dictionary, we have both the explanation, and the diagram:

Partial image of an annotated diagram of BB-8; the text appears below


An internal orbiculate motivator rolls BB-8's body, while its head is kept perched atop the sphere with magnetic casters. Wireless telemetry between the head and body removes the need to keep the head tethered to a single contact point. When BB-8 needs extra stability or must traverse areas it can't roll through, it fires compressed liquid cable launchers that then reel the droid into hard-to-reach spots.

Another partial image of BB-8, showing a cut-away of one quadrant of the spherical body.  Among the visible annotations, "Magnetic caster" and its indicator line are circled (ellipsed?) in red.  Another red circle highlights the caster itself, a spiral-wound cylinder about a sixth the height of the visible quadrant, mounted just inside BB-8's outer shell

  • 2
    Good answer, DVK. I fully expected that something more detailed than a pillow would arise after the film was released. :-)
    – Praxis
    Commented Dec 21, 2015 at 5:00
  • Is there any mention what would happen if BB8 would lose power? Just loosing the head would look like a design flaw...
    – bdecaf
    Commented Dec 21, 2015 at 8:08
  • 2
    @bdecaf: Quickening? Commented Dec 21, 2015 at 11:08
  • 1
    @DVK - Wouldn't that mean that his designation would be B-Oni-1?
    – Valorum
    Commented Jan 6, 2016 at 20:36
  • @Richard: THWACK!
    – Martha
    Commented Jan 6, 2016 at 20:49


As commenters have noted below the question, the obvious answer is magnets, but it was surprisingly hard to find an official confirmation of this.

The most common in-universe schematic of BB-8 that seems to be going around is the one directly below, which comes from a licensed card set. It unfortunately does not highlight the components or mechanism responsible for keeping the head attached to the body:

line drawing of BB-8 in full side view with annotations identifying a few surface features.  The drawing also has inset top and bottom views, unlabeled

Branching out, I found this licensed cushion that is available, for example, at StarWarsBedroom.com (link redirected to archived version):

Throw pillow with a sketched image of BB-8 against a ruled grid.  Annotation as below

The sketch on the cushion has an arrow labelled "Magnetic Balancing", pointing at where the head sits on the body.

  • 2
    +1 for invoking to the ubiquitous this pillow meme Commented Dec 14, 2015 at 21:59
  • @ThePopMachine : I'm always on the lookout for an opportunity to extend the meme. Anything else you need for this answer? :-)
    – Praxis
    Commented Dec 15, 2015 at 0:00
  • this pillow meme?
    – user20155
    Commented Dec 15, 2015 at 0:57
  • 1
    @Praxis: I believe you mean, I'm always on the lookout for an opportunity to nag about acceptance Commented Dec 15, 2015 at 1:25
  • @LegoStormtroopr: meta.scifi.stackexchange.com/questions/1289/… Commented Dec 15, 2015 at 1:48

Its my understanding that they actually made a working, patented roller-ball droid (besides the various props they created). It used MAGNETS, like everyone said.

Here appears to be the patent and here is some more information.

  • 3
    Welcome to SFF:SE. While your answer is interesting, we should point out that the question is asking for in-universe (i.e. how is BB-8 supposed to work from the point of view of the story).
    – Praxis
    Commented Dec 14, 2015 at 23:33

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