HOW DO WE POWER A 6-YEAR JOURNEY? 

Jupiter’s orbit is five times farther from the sun than Earth’s location, so the giant planet receives about 25 times less sunlight than Earth. Juno is the first solar-powered spacecraft designed to operate at such a great distance from the sun, thus its solar panels are quite large to generate sufficient power.

The Juno orbit and spacecraft orientation have been carefully designed so that Juno’s solar panels face the Sun most of the time (except during engine burns). Therefore, the solar panels are illuminated by the sun for the entire mission. This means the spacecraft has continuous access to its power source. Juno only passes into eclipse once after launch, for a few minutes following the Earth flyby in 2013.

HOW DO SOLAR CELLS WORK? 

A solar cell converts sunlight into electricity. Materials within the cell have special properties that cause electrons to flow from them when struck by light. Flowing electrons are what we call electricity. Not all of the energy of the sunlight is converted to electricity – some of the light is reflected and some is turned into heat. The more light a solar cell converts into electricity, the more efficient the cell. Juno’s very efficient solar arrays benefit from many advances in solar cell technology achieved over the past 20 years.