Jupiter ready for close-up with Juno mission

    Named for a Roman goddess, Juno should arrive and begin sending back photos on July 4. Launched in 2011, the $1.1 billion mission hinges on how the basketball-court sized spacecraft performs in Jupiter’s intense radiation environment, scientists said during a televised press conference June 16. Here is the rundown:

Why do scientists use the word "scary" when talking about Jupiter? “Jupiter has the scariest radiation environment of any planet in the solar system,” said Heidi Becker, radiation monitoring investigation lead at NASA's Jet Propulsion Laboratory in California. “It’s the harshest. It’s the most intense and it hasn’t been fully explored yet. …Jupiter’s magnetic field has trapped a huge population of electrons and accelerated them to the point where they are moving at almost the speed of light. They are incredibly penetrating. They are damaging to electronics, and they can create enough noise on the detector to totally blind the camera.”
    Once electrons hit a spacecraft, they ricochet and release energy, she said, “creating secondary photons and particles which then ricochet. It’s like a spray of radiation bullets.”
    Initially, Juno is protected by its polar orbit, but as the mission progresses, Becker added, it will descend “into the harshest equatorial region of the radiation belts.”
     Juno is equipped with shields to protect it from radiation. Indeed, one scientist likened it to an "armored tank." Without the extra protection, it wouldn’t be possible to navigate the spacecraft.

What do scientists want to learn? The mission has ambitious goals -- scientists want the “recipe” for the solar system itself. “How do you make the planets in our solar system?” asked Scott Bolton, Juno principal investigator and associate vice president of the Space Science and Engineering Division at Southwest Research Institute in San Antonio. “Jupiter holds a very unique position in helping us learn about that recipe, because it was the first planet to form.”
    Jupiter looks a lot like the sun, he explained, almost all hydrogen and helium. “But when you look closely at the composition of Jupiter, you learn that it has an enrichment of what scientists call ‘heavy elements,’ all the elements beyond helium in mass – the carbon, the nitrogen, the sulfur, the noble gases. Jupiter is enriched with these elements, compared to the sun. We don’t know exactly how that happened. But we know it is really important. … The stuff that Jupiter has more of is what we are all made out of. It is what the Earth is made out of; it is what life comes from. Learning about that history is really critical if we’re going to figure out how we got here and learn about the Earth and how we find other systems like the Earth elsewhere.”

Does Jupiter have a core? Jupiter is a ball of gas, right? But “if there is a core of heavy elements, a bunch of rocky, icy material squeezed down in the center of Jupiter, it tells us something about the early processing in the solar system," Bolton explained. "That means that the rocks must have formed before Jupiter did; essentially, Jupiter got built around those rocks.” 

What’s up with Jupiter’s northern lights? Juno will be the first spacecraft to go over the poles of Jupiter. “As we fly over the poles, we’re flying right over Jupiter’s intense aurora, its northern and southern lights,” Bolton explained. “These are the strongest aurora emissions in the entire solar system.”  
    From that flyover, scientists will learn how auroras work in general.

Given that all goes well, will there be jaw-dropping photos? Yes. The “Juno cam” will provide the first views of Jupiter’s poles. It will also show close-up views of Jupiter. The Juno cam is a public camera, and anyone can log into a website and vote on the direction in which it will point.
    An instrument on the spacecraft will see beneath cloud tops. That makes a difference because scientists don't know the depth of specific regions -- for example, the great red spot.

Why will Juno's mission end in 2018? In the future, NASA will study one of Jupiter's moons, Europa, said Rick Nybakken, Juno project manager, Jet Propulsion Laboratory California. Scientists suspect there could be life on Europa. "The last thing you want to have happen is get there and find out it's been contaminated by organisms from Earth. And so they have a program called planetary protection. And one of the requirements we have is to have a very low likelihood that we'll ever hit Europa and contaminate it."
     So after the Juno spacecraft completes its mission, it will fly into Jupiter. "Destroying the spacecraft that way is the way that we hope ensure that we will not hit Europa in the future," he said.

Are there any passengers? The spacecraft carries three Lego figurines made of spacecraft-grade aluminum depicting the goddess Juno, the god Jupiter and the Italian astronomer and scholar Galileo.  

      Related:

     Jupiter's northern lights triggered by storms

     Jupiter's moon may have balance for life

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