Close-up of a single solar-array cell

Close-up of a single solar-array cell.

Rosetta will be the first space mission to journey beyond the main asteroid belt and rely solely on solar cells for power generation, rather than the traditional radio-isotope thermal generators. The new solar-cell technology used on the Orbiter’s two giant solar panels allows it to operate over 800 million km from the Sun, where sunlight levels are only 4% those on Earth.