This video about Spectrolab's spacecraft power systems mentions Juno several times and it looks like the Juno panels are shown at several points in the video. Multi-junction cells are discussed, they have higher efficiency than silicon and so were the obvious choice for Juno.
But I was confused when I saw this:
Spectrolab's solar cells are approximately 30% efficient in space and exceed 40% efficiency in terrestrial applications.
Why is there such a large difference in these values? Is photovoltaic efficiency defined differently for space and terrestrial applications?
Although I normally advise against taking a percent of a percent because it can be confusing:
$$ 1- \frac {\text{approximately 30%}} {\text{exceeding 40%}} \approx \text{25% less} $$
above: Screen shot from the video found here: