NASA's dangerous Juno mission: Unravel Jupiter's secrets and solve the mysteries of life

July 4, 2016 by Amina Khan, Los Angeles Times
Credit: Southwest Research Institute

Late at night, when the halls around her were empty, Heidi Becker positioned her subject in the crosshairs of an electron-shooting linear accelerator. Along with her companions, she arranged a cartload of heavy lead bricks to make sure the deadly radiation would hit only its intended target.

By day, the accelerator at the Curie Institute hospital in Paris was used to kill tumors in cancer patients. This time, its lethal gaze would be aimed at an early version of the star tracker aboard NASA's Juno spacecraft, which is set to enter Jupiter's orbit on July 4.

The instrument will play a key role in helping scientists determine Juno's orientation as it takes billions of high-definition measurements of Jupiter's punishing magnetic field. At the hospital, Becker and her fellow engineers were doing their best to mimic the lethal forces the star tracker would face. They wanted to be sure that it would survive.

Jupiter "is the scariest place," said Becker, who leads the mission's radiation monitoring investigation at NASA's Jet Propulsion Laboratory. "There isn't anything like it anywhere else."

It's not your typical test for spacecraft parts, but this is no typical destination.

Monday night, if all goes as planned, Juno will complete its looping, 1.8-billion-mile journey and slip into Jupiter's embrace - the first spacecraft to orbit the gas giant since Galileo in 2003.

The rewards of the $1.1 billion mission are clear: to probe Jupiter's deeply held secrets and solve long-standing mysteries about the origins of our solar system, of Earth and, by extension, of life itself.

But as it explores the gas giant, Juno will have to fight for its own life.

The craft will fly within 2,600 miles of the planet, closer than any previous satellite. As it completes 37 orbits over 20 months, Juno will have to withstand a brutal onslaught of radiation.

The high-energy electrons around Jupiter are like machine-gun fire: constant and extremely penetrating. After the initial volley, each ricocheting particle releases a spray of subatomic shrapnel that does even more damage.

"Jupiter is really, really hazardous," said Scott Bolton, Juno's principal investigator at the Southwest Research Institute. To withstand the barrage of high-energy electrons, most of Juno's electronics are inside a titanium vault. "We're an armored tank."

Like its mythological counterpart, Jupiter is king of its realm: the largest and most powerful planet, more than twice as massive as all the others combined, and the first to be born from the swirling disk of gas and dust that once surrounded our nascent star.

It is also the most sun-like planet: made mostly of hydrogen and helium, with traces of heavier elements thrown in. In fact, size aside, the main difference between Jupiter and the sun is that the planet has a larger share of those trace elements, including carbon, nitrogen and sulfur.

"We don't know how Jupiter got enriched, but we know it's very important," Bolton said. "Because the stuff that Jupiter has more of is what we're all made out of. It's what the Earth is made out of. It's what life comes from."

Four centuries ago, Galileo Galilei's observations of the planet and its four largest moons demonstrated that the Earth was not the center of the universe - a discovery that ultimately landed him under house arrest until his death. And yet, large as this storm-eyed, striped giant looms in our minds, we know remarkably little about it.

For example, scientists don't know if Jupiter's Great Red Spot, that giant storm that could swallow the entire Earth, is merely an atmospheric phenomenon or a structure that penetrates far into the planet.

Nor do they know how much oxygen or water lies within the planet, a mystery that only deepened after NASA's Galileo probe plunged into the gas giant in 1995 and found it to be surprisingly dry.

Hydrogen is by far the most abundant element in the universe, and oxygen ranks third. Together, that should have made for a lot of water - that is, if Jupiter really does hold within it the secret recipe for our solar system.

Perhaps the Galileo probe did not reach deep enough. Perhaps it hit a dry spot. Or perhaps scientists' theories of planetary formation are completely wrong.

"That one single number, the water content, will tell us a whole lot," said Steven Levin, Juno's project scientist at JPL in La Canada Flintridge in the Los Angeles area.

Juno will also be the first mission to orbit the planet's poles, documenting its powerful northern and southern auroras, studying its colossal magnetic field up close and perhaps learning what exactly powers it. After completing its nearly five-year journey from Earth, the spacecraft will take a highly elliptical orbit, crossing from one pole to the other in just two hours, then shooting far out into space for about two weeks. This will allow researchers to compare their measurements close to and farther from the planet's influence.

The deepest mystery lies at the heart of the gas giant - scientists want to find out whether it has a hard center, like an inverse Tootsie Pop. Researchers aren't sure if Jupiter hides a solid core of heavy metals such as iron and nickel, or whether it's filled with hydrogen that has been compressed so much that its electrons have been squeezed off, allowing it to behave like a metal. If there's rocky material in the core, it may hint that Jupiter formed later in the solar system's history, after chunks of rock had time to coalesce out of the dust.

Juno is a giant spinning three-armed pinwheel whose 30-foot-long solar panels make it about the size of a basketball court. So far from the sun, those panels only provide roughly 500 watts of electricity - not enough to power a hair dryer, but perfect for this efficient suite of instruments.

Juno's infrared spectrometer and ultraviolet spectrograph will study the planet's auroras in different wavelengths of light. A microwave sensor will use radio waves to search for water and ammonia hidden beneath the thick cloud-tops.

JunoCam, a visible-light camera, will be the first to take close-up pictures of the planet's poles. The mission team is asking members of the public to help pick interesting targets and process the resulting images.

Although it flies above Jupiter's atmosphere, Juno will peer deep into the planet. A magnetometer, perched at the end of one solar-paneled arm, will create a 3D map of the planet's enormous magnetic field, which should shed light on the internal dynamics that power it. Another experiment will map the planet's interior structure by measuring the tiny shifts in radio signals caused by subtle gravitational tugs that distort the spacecraft's orbit.

Unlike many NASA missions, Juno's 20-month investigation probably won't be extended by much: The spacecraft, armored as it is against Jupiter's harsh environment, can't protect its systems indefinitely. And scientists do not want to risk having a radiation-fried satellite go off-course and potentially contaminate a nearby moon like Europa, one of the solar system's best candidates for finding microbial life.

Ultimately, Juno will plunge into Jupiter's atmosphere, succumbing to the punishing forces within.

The end may be a tad bittersweet for such a groundbreaking mission, said Rick Nybakken, Juno's project manager at JPL.

"We all feel that way," he said. "But we also know we've got a lot ahead of us."

Explore further: NASA spacecraft barreling toward Jupiter for July 4 meetup

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13 comments

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antiantigoracle
Jul 04, 2016
This comment has been removed by a moderator.
wduckss
1 / 5 (14) Jul 04, 2016
"..scientists Want to find out whether it has a hard center .."

In line with the higher emission of heat radiation is not comes to hard center already melted, the strength of the magnetic field leads to the existence of crust and different rotation center and crust.
Molten core retains the average density of the planet at 1.3 g / cm2 as opposed to hard cores.

I hope that the authors of articles will respect science and adhere to the goals of NASA.
HeloMenelo
2.7 / 5 (12) Jul 04, 2016
@FartY
Gonna go around trolling every story posting the same thing? Fine. I will too.

Eat shit and bark at the moon, you goddamn xtian tool!

a...aaa...aaaa Temper monkey...trolling for over a decade has made you the super bonobo you are today :D And for that... yup... you guessed it, you earn another banana... well done... :D

Tuxford
1.3 / 5 (14) Jul 04, 2016
"..scientists Want to find out whether it has a hard center .."

In line with the higher emission of heat radiation is not comes to hard center already melted, the strength of the magnetic field leads to the existence of crust and different rotation center and crust.
Molten core retains the average density of the planet at 1.3 g / cm2 as opposed to hard cores.

I hope that the authors of articles will respect science and adhere to the goals of NASA.

Place your bets here!

I bet it has a soft center, generating new gas therein, eventually growing the planet into a star. One day, we too will be a binary system, with two dawns a day.
Tektrix
4.4 / 5 (13) Jul 05, 2016
This kind of infatuation with playing God is silly and doesn't belong in science.

~God is silly and doesn't belong in science. ~ FTFY

torbjorn_b_g_larsson
4.5 / 5 (15) Jul 05, 2016
they are as far away from solving this "mystery" as when they started.


No, "they" (scientists) are not, as anyone who read their output would well know. Not only have science ecplored the problem for a few decades (c.f. evolution beginning), there are now two complete, consistent and fully capable theories (soup theory, vent theory) that has sessions describing testing at major conferences.

It may take another few decades before one of the two theories are rejected as not worthy (c.f. evolution again), but there is no reason to believe it won't happen - evolution taught us how to test biology.

Finally, your magic superstition is a kind of infatuation with playing 'God' - trying to tell nature how it should behave - which is silly and doesn't belong in science.
DonCarloFantasia
Jul 06, 2016
This comment has been removed by a moderator.
BongThePuffin
Jul 06, 2016
This comment has been removed by a moderator.
gkam
1 / 5 (4) Jul 06, 2016
They failed to tell us the power of the electron beam. How many MeV?
691Boat
5 / 5 (6) Jul 06, 2016
Uncle Ira
4.4 / 5 (7) Jul 06, 2016
They failed to tell us the power of the electron beam. How many MeV?


Well Cher, maybe I can help you. Since they are not depending on the "power" of the beam, which a person with engineering and science "experience" would call the "energy" of the particles they probably are not measuring in eVs. They are probably measuring using the Gray Scale units that measure ionizing radiation.

The Skippys over there in Paris use a machine that makes up to 25 or so Gy's. For peoples they use about 15 or so Gy's but maybe they use the whole 25 Gy's for seeing how tough the Juno type thing is.

Now that you know that, what you going to do with your new found knowledges?
gkam
1 / 5 (6) Jul 06, 2016
Silly kid, the electron beam is rated in eV of acceleration. The ones we used to make heat-shrink materials and wire for spacecraft were from 0.5 to 3.0 MeV.
Uncle Ira
4.4 / 5 (7) Jul 06, 2016
Silly kid, the electron beam is rated in eV of acceleration. The ones we used to make heat-shrink materials and wire for spacecraft were from 0.5 to 3.0 MeV.


The machine they are using output is measured in Gy's. Gee wiz, I wonder why they would use such a machine, eh? Because they are seeing how much ionizing radiation the instruments can take before they fail? Do you even know what Gray Scale is? It the way scientists quantify, what?, that's right, IONIZING RADIATION.

For an idiot, you are remarkable stupid.

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