I'm no engineer, but if I was making a vessel with extending sails, solar panels, mast, antennae, etc. I would make them widest close to the core. But Juno's solar panels narrow toward the core as shown in the image below and get wider further from core. Why is this?

Image from NASA.gov

  • $\begingroup$ So they don't really taper so much. It's just that one is smaller. And I would imagine that it is smaller because of the science instruments in the body of the spacecraft. You don't want them being blocked by the solar panels. And those panels are huge. Here is a picture of one wing in the JPL Spacecraft Assembly cleanroom. $\endgroup$
    – Phiteros
    Jul 8, 2016 at 5:05
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    $\begingroup$ I wonder if it might have something to do with how they were folded inside the fairing. $\endgroup$
    – SF.
    Jul 8, 2016 at 9:50
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    $\begingroup$ "...if I was making a vessel with extending sails... I would make them widest closest to the core." Just curious, why? What engineering considerations would you use? Stating that would help to identify what other spacecraft engineering considerations you'd like to find out about here. $\endgroup$
    – uhoh
    Jul 8, 2016 at 10:03
  • $\begingroup$ @SF: I don't think so. See youtu.be/sNMOOjemMG8?t=10s $\endgroup$
    – PearsonArtPhoto
    Jul 8, 2016 at 13:32
  • $\begingroup$ @uhoh I'm trying to think of a reason that doesn't boil down to gravity or pressure. But I can't. Maybe I'm too used to Earth-bound engineering. $\endgroup$
    – Coomie
    Jul 9, 2016 at 4:23

2 Answers 2


At first I thought it had something to do with reinforcing the wings, but they cannot support themselves in gravity anyway. Looking into it further I found this:

"The layout and size of the panels are oriented in that nice symmetrical hexagon so the instruments will have an unconstrained field of view," Gehling said.

(NASA: Juno's Solar Cells Ready to Light Up Jupiter Mission)

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    $\begingroup$ I think this answer answers a different question. That quote explains the panels' orientation, but not their relative widths. $\endgroup$
    – Anko
    Jul 9, 2016 at 2:14

Not really familiar with the vehicle or the specifics of how it was mated to its launch vehicle but my first reaction would be that it probably is driven by either a packing constraint or possibly is related to the specifics of the deployment mechanism or sequence.


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