NASA's Juno page says

The Juno spacecraft launched aboard an Atlas V-551 rocket from Cape Canaveral, Fla., on Aug. 5, 2011, and will reach Jupiter in July 2016. The spacecraft will orbit Jupiter 32 times, skimming to within 3,100 miles (5,000 kilometers) above the planet's cloud tops, for approximately one year.

The environment around Jupiter itself is reportedly corrosive thanks to Io. In addition, the craft may suffer mechanical/tidal stresses from Jupiter & her family of moons.

  • How were Juno's solar arrays tested for mechanical/tidal stresses from Jupiter, and her family of moons?

  • Will Juno be able to do science if a single array remains functional?

  • What is the typical power redundancy built into a spacecraft?
  • 1
    $\begingroup$ The stress to the solar arrays from earth's gravity and from the launch is much bigger than tidal stresses from Jupiter. When the arrays are unfolded, an ignition of the main engine of the spacecraft will cause more stress than tidal forces. $\endgroup$
    – Uwe
    Sep 16, 2017 at 10:51

1 Answer 1


Solar arrays are wired as many strings of cells, where each string is a series of solar cells with the proper number to provide the required voltage. Those strings connected to each other in parallel to add their currents to provide the required total power.

An individual cell failure will take out one entire string, so the resiliency against cell failures can be seen in the number of strings. The Juno spacecraft has a complicated arrangement of short, medium, and long strings to handle the large range of solar distances that the mission operates over. What matters for your question are the short strings which are used at Jupiter. Juno has 848 short strings, so it is quite resilient to a few individual cell failures.

There are no significant stresses on the solar panels from tidal forces. Juno's polar orbit keeps it out of the radiation belts (e.g. Io's) most of the time. However radiation tolerance was still a driving design factor for that mission.

Juno's orbit and the radiation belts


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.