NASA Juno Probe A Solar Powered Voyager

Powered by 650 square feet of solar panels, Juno is spinning its way to Jupiter. Don’t hold your breath for new insights about the oldest and most complex planet in our solar system, however: After its launch last week, Juno took less than a day to speed 250,000 miles from Earth – the distance from here to the moon – but Jupiter is another 1,740 million miles away, so it will take five years to get there.

NASA has done unmanned trips deep into space before, of course, but it’s never done so relying on solar power to keep a craft’s systems running. Juno’s ability to go solar is possible in part, the agency said, by advances that make today’s solar cells 50 percent more efficient – and radiation-tolerant – compared with those available a generation ago.

solar-powered Juno

image via NASA

That’s especially important because the farther a spacecraft travels from the sun, the less power it can generate from the receding star. Even with its three solar arrays made up of 11 solar panels and one MAG boom, Juno’s power generation will fall from 14 kilowatts near Earth to 400 watts out near Jupiter, which receives less than 5 percent of the solar radiation the Earth does.

Juno launch, solar powered Jupiter probe

image via NASA

Juno’s principal goal, NASA said, is to peer beneath Jupiter’s dense cloud cover and help scientists gain a better understanding of the origin and evolution of the planet. “With its suite of science instruments, Juno will investigate the existence of a solid planetary core, map Jupiter’s intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet’s auroras,” NASA said. See the PDF press kit for all the details on the craft and the mission.

This is the second mission in NASA’s New Frontiers Program, with New Horizons, launched in 2006 and scheduled to reach Pluto’s moon Charon in 2015, coming first.

Pete Danko is a writer and editor based in Portland, Oregon. His work has appeared in Breaking Energy, National Geographic's Energy Blog, The New York Times, San Francisco Chronicle and elsewhere.