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Are the JWST solar panels protected from solar flares and would massive flares reduce the life of the JWST?

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    $\begingroup$ The danger posed by solar flares to satellites is more serious to the on-board electronics than to solar panels. To probe further: solarstorms.org/SWChapter6.html $\endgroup$
    – Ng Ph
    Jan 4 at 19:08
  • $\begingroup$ Won't the five layer sunshield protect the electroncics? $\endgroup$
    – TelStar
    Jan 5 at 9:12
  • $\begingroup$ AFAIK, the electronics are on the warm side of JWST (and need to be). They are already heavily protected by their casings, but you cannot exclude that the X-rays from strong solar flares occasionally upset some of them. Space is a harsh environments. $\endgroup$
    – Ng Ph
    Jan 5 at 10:32

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Solar panels have been used on spacecraft since the late 1950s. Perhaps one of the longest running set of actively used solar panels is on the Wind, which just turned 27 years old on November 1, 2021. If you look at the figure below (from the 2020 Senior Review proposal at the bottom of the above link), you will see a single plot showing the solar panel current output versus time (shows data from Jan. 1, 1995 to Dec. 31, 2019). You will notice there appear to be two different, roughly linear slopes in the panel output versus time. The first one ends after ~2004. This corresponds to the time when Wind went to the Earth-Sun L1 point permanently, i.e., it stopped passing through the terrestrial radiation belts.

Solar array current output in amperes for the WIND spacecraft as a function of time.

JWST, for comparison, will only pass through the belts a few times at most on its way to the Earth-Sun L2 point. Therefore, the biggest degredation will be the usual solar radiation (whether photons or charged particles from the solar wind.

Note that many spacecraft solar panels can perform "self healing" processes (I think this is called annealing, if memory serves me but please correct if anyone knows the correct term) to help recuperate the crystalline silicon or gallium arsenide material that converts the ionizing photons into an electric current. The bigger issue is usually with the conductive glass that covers the panels. Over time, ionizing radiation causes it to "blacken" and fewer and fewer photons can penetrate. This is the main reason why the Wind spacecraft's current output decreases over time.

Are the JWST solar panels protected from solar flares and would massive flares reduce the life of the JWST?

I very much doubt solar panel degredation will limit the lifespan of JWST. If memory serves me, the thing which will definitely end the mission are either it running out of fuel or running out of coolant.

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    $\begingroup$ Thanks for answering. $\endgroup$
    – TelStar
    Jan 4 at 17:25
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    $\begingroup$ There is overcurrent protection on at least some panels out there... $\endgroup$
    – Jon Custer
    Jan 4 at 21:08

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