Environment & Science

Success! Juno spacecraft is orbiting Jupiter after risky maneuver

This illustration show's NASA's Juno mission approaching Jupiter. Juno used distant stars to chart its course across the void.
This illustration show's NASA's Juno mission approaching Jupiter. Juno used distant stars to chart its course across the void.
NASA/JPL-Caltech
This illustration show's NASA's Juno mission approaching Jupiter. Juno used distant stars to chart its course across the void.
Key members of the Juno team held a press conference after the successful insertion of the spacecraft into orbit around Jupiter.
Sanden Totten / KPCC


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After five years and a nearly 2-billion-mile journey through the solar system, NASA's Juno probe has reached its target: Jupiter.

Everything went pretty much as planned on the evening of July 4th as Juno fired its rockets to start a 35-minute burn that helped it enter orbit around the gas giant.

Things were tense at NASA's Jet Propulsion Laboratory as scientists, engineers and space fans waited for a signal from the spacecraft letting them know the probe had arrived.

When that signal finally came, at 8:53 pm PTD, the mission control room broke out with clapping and cheers.

"Welcome to Jupiter," said Michael M. Watkins, the new director of the Jet Propulsion Laboratory on NASA TV shortly after Juno's arrival.

The duration of the engine burn was only one second off what was planned, quite a feat given how much could have gone wrong on this mission.

Shortly after that burn, Juno swung back around to face the sun with its 18,698 individual solar cells that will power its journey.

The Juno spacecraft is solar-powered. An engineering model shows one wing during a media preview at Jet Propulsion Laboratory in Pasadena on Thursday morning, June 9, 2016. The actual array is made up of panels about the size of a city bus.
The Juno spacecraft is solar-powered. An engineering model shows one wing during a media preview at Jet Propulsion Laboratory in Pasadena on Thursday morning, June 9, 2016. The actual array is made up of panels about the size of a city bus.
Maya Sugarman/KPCC

"It's almost like a dream coming true right here," remarked Juno principal investigator Scott Bolton at a press conference after the orbital insertion.

As part of that event, Bolton introduced a film taken by Juno as it approached Jupiter showing the planet's moons orbiting around the gas giant.

"For the first time, all of us together, will see the true harmony in nature," he said before playing the video. It shows a short animation before the footage of Jupiter and its moons.

The motion in the video was shot over 17 days and condensed to about three minutes, Bolton noted, "which I think it more enjoyable."

Juno Approach of Jupiter

The Juno spacecraft will give us earthlings new information about the largest planet in our celestial neighborhood.

In fact, we still know relatively little about how Jupiter formed or how it rotates inside. Sure, it's covered in dynamic bands of colorful storms, but are those relatively shallow with a different structure underneath or do these storms penetrate to the heart of the gas giant?

Another question Juno hopes to answer is whether or not there's a rocky core at the center of the planet or if it is all gas.

Understanding how Jupiter developed could provide valuable clues about the formation of our early solar system, since scientists believe Jupiter was the first planet born after our sun coalesced and ignited.

A diagram showing the scientific instruments on the Juno spacecraft.
A diagram showing the scientific instruments on the Juno spacecraft.
NASA / JPL

Because of its size, Jupiter likely helped clear much of the solar system of debris, leaving space for planets like Earth to form and possibly shielding them from larger impacts.

Of course, studying Jupiter is not without risk.

“Jupiter is the biggest, baddest planet in the solar system,” said Steve Levin, Juno project scientist.

That includes having the most intense radiation field in the solar system.

That radiation comes from variety of places -- including particles stemming from solar wind and even eruptions on Jupiter’s moon Io. They get trapped by Jupiter’s powerful magnetic field and become highly charged, some end up moving near the speed of light.

Even though these particles are tiny, they can cause huge problems if they strike sensitive electronics like the kind on Juno.

That's why Monday's maneuver was so risky.

Stray particles could have struck certain circuits, causing systems to reboot just as the craft was about to fire rockets for orbital insertion.

Fortunately, that didn't happen and the spacecraft carried out its flight as planned.

However, it's still subject to that extreme radiation, which overtime can damage and eventually ruin important gear.

That's why NASA took precautions by encasing most of the electronics in a titanium box that's roughly the size of a college dorm fridge.

"That was a new idea for Juno," Levin commented.

In the past, NASA would just shield specific parts rather than group everything into one area and wall it off.

The lessons learned from Juno could be applied to future missions, including one to Jupiter's moon Europa, according to Mr. Geoffrey Yoder, the acting Associate Administrator for NASA's Science Mission Directorate.

"Europa has a really, really tough radiation environment," Yoder added.

The camera on Juno however doesn't really work if it's stuck in a titanium box, so when the company Malin Space Science Systems designed it, they just shielded the key electronics.

A model of a two-megapixel camera on the Juno spacecraft shows thick casing protecting the lens and sensor from Jupiter's intense radiation field.
A model of a two-megapixel camera on the Juno spacecraft shows thick casing protecting the lens and sensor from Jupiter's intense radiation field.
Maya Sugarman/KPCC

Elsa Jensen with Malin said once Juno's camera is up and running, the public will be invited to suggest places on Jupiter for it to photograph. The targets with the most votes will win and in this way anyone can participate in the mission, she explained.

Still, it will be awhile before we'll see those pictures or any other scientific investigations of Jupiter.

Juno's scientific instruments were turned off for the orbital insertion and won't go back online for several more days. It'll be longer still before NASA starts receiving observational data from the craft, Levin noted.

"What I am really looking forward to is getting up close and personal with Jupiter in about 53 days," he said.

Sure, that feels like a long wait right now, but that's nothing compared to the years spent waiting to get to this point.