It’s already broken records—the vessel is the farthest solar-powered craft that's ventured from Earth. But Juno, NASA’s unmanned Jupiter orbiter, isn’t done yet. On July 4, the craft will arrive at the Jovian giant itself and begin a fascinating mission with a bittersweet end. Today, NASA held a press conference to discuss just how things will go down on the Fourth of July. Here are five things to know about Juno’s upcoming rendezvous with the solar system’s largest planet:
It’s come a long way, baby...
By the time Juno gets to Jupiter, it will have traveled five years and 1,740 million miles to reach the fifth planet from the Sun. But it won’t be done yet: The orbiter still has to spend time circling the gigantic planet, which will add another 348 million miles to its journey before it ends its mission in October 2017. By the time Juno is no more, it will have traveled a whopping 2,106 million miles since its 2011 launch.
…and its job is barely done
Getting to Jupiter may seem like the hard part, but Juno still has much to accomplish. Now, say officials, it’s time for the fun part: studying Jupiter itself.
“We still have questions, and Juno is poised to begin to answer them,” said Diane Brown, Juno program executive. Jupiter’s unsolved mysteries include what Juno’s principal investigator, Scott Bolton, calls “the recipe for solar systems.” It’s thought that after the Sun formed, the dust and gas that remained became a gas giant. The rest appears to have been spit out into the solar system—and eventually formed other planets and even people.
“We are the leftovers of the leftovers,” Bolton said. Right now, researchers think that clues to the origins of the solar system are hidden within the planet’s atmosphere, which could help confirm Jupiter's potentially important role in the formation of Earth and other planets. The makeup of Jupiter may also include a rocky core—one that scientists aren’t even sure exists, Bolton adds. But if it's there, researchers think they may be able to isolate where, when and how the planet formed.
Then there’s Jupiter's magnetosphere. Juno will fly over the planet’s poles, which are home to the strongest aurorae in the solar system. “Jupiter is a planet on steroids,” said Bolton. “Everything about it is extreme.”
Speaking of extreme: Radiation from the planet is brutal, but the team has planned for it. Even in orbit, Juno is expected to experience what Heidi Becker, the team’s radiation monitoring lead, called “the scariest radiation” ever encountered by a NASA craft. Becker said that the craft is wearing the equivalent of “a suit of armor…and a bulletproof vest” that will make it able to navigate Juno without falling to pieces. Other program officials confirmed that the orbit is on track, so any deviations from NASA’s strict schedule will be surprises.
NASA loves July 4 landings
Think you’ve heard about a Fourth of July space event before? Good memory: NASA has timed two other major space events on July 4 in recent years. The first was the landing of the Mars Pathfinder mission on July 4, 1997. Eight years later, on July 4, 2005, the agency’s Deep Impact mission landed on Comet Tempel 1—the first mission to explore a comet’s interior. NASA can be forgiven for its patriotic timing: After all, space exploration is not just symbolic of freedom, but arguably one of the United States’ most towering achievements.
Juno’s destiny is kind of sad
Though it would be amazing if Juno were able to orbit Jupiter forever, it’s just not possible. And if it did, scientists would miss out on a one-of-a-kind opportunity to study Jupiter’s atmosphere. At the end of the mission, Juno will pierce the planet’s cloudy veil, looking beneath this swirling mass that give it those characteristic stripes. There’s a downside, though: Daring to enter Jupiter’s gassy atmosphere means sacrificing the mission itself. Once Juno gets beneath Jupiter’s clouds, it will burn up in what Spaceflight 101 calls “a furious end.”
Want to come along for the ride? Check out JunoCam, a camera mounted on the craft that the public can vote to point in different directions. Participants can also use project data to create the first images of the planet's poles and share them with the world. NASA has also planned a number of media events and ongoing coverage of the craft as it enters orbit. Stay tuned on July 4—it's gonna be a historic (if not particularly wild) ride.