Juno Is Now Humanity’s Furthest-Flung Solar-Powered Craft

Armed with over 18,000 solar cells, the Jupiter orbiter is taking solar-fueled space exploration to new lengths

An artist's rendition of Juno in orbit around Jupiter. The craft is powered entirely by the sun's rays. NASA

Juno, the unmanned craft that’s part of NASA’s New Frontiers program, is still months away from engaging in its primary mission to circle Jupiter. But it’s already breaking records. On January 13, the orbiter beat out the European Space Agency’s Rosetta craft as the most distant solar-powered craft in space.

In a release about the milestone, NASA writes that Juno is now over 493 million miles away from the sun—five times further from the sun than Earth. That’s quite an achievement for a craft that’s powered by the star.

Since Jupiter gets 25 times less sunlight than Earth, NASA had to give it huge solar panels to make its mission viable. Juno has three solar panels, over 18,000 solar cells and nearly 750 pounds of solar arrays.

The sun-powered craft will help scientists better understand the history of the solar system when it arrives at Jupiter on July 4. Juno is the first Jovian mission that hasn’t relied on nuclear power to function.

Unlike other far-off crafts, Juno isn’t destined to fly further and further into space. Rather, it will burn up in Jupiter’s dense atmosphere as it descends in search of even better scientific readings. (This summary of the craft’s entire trajectory has all the grisly details.) That’s in contrast to crafts like Voyager I and Voyager II, which are both fueled by plutonium and have hit interstellar space and the heliosheath, respectively.

So Juno isn’t the furthest craft in space. But the fact that it has made it so far only on the power of the sun is an incredible feat. NASA thinks so too—but is urging the public to keep their eyes on the prize.

“It is cool we got the record and that our dedicated team of engineers and scientists can chalk up another first in space exploration,” says Scott Bolton, Juno’s principal investigator, in the press release. “But the best is yet to come. We are achieving these records and venturing so far out for a reason—to better understand the biggest world in our solar system and thereby better understand where we came from.”

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