NASA's Juno Probe Is Closing in on Jupiter

After five years of traveling through deep space, the final frontier, NASA's Juno spacecraft is expected to reach Jupiter on Monday. If everything goes well, Juno, a 400-pound titanium box strapped to a 66-foot-long solar panel, will dig up more information about the massive gas giant than we've ever had access to before, giving NASA scientists and the rest of us a peek at the roiling, poisonous thunder clouds that lie beneath the planet's upper atmosphere. 

Entering Jupiter's orbit will only be the beginning of Juno's Jupiter adventure. The probe will spend about a year mapping the entire surface of the planet while nine scientific instruments work to probe the planet's interior makeup and its powerful magnetic field.

Jupiter, like the sun, is made up of helium and hydrogen, which is part of why scientists suspect the planet was a key player in forming our solar system, according to NASA. The planet sucked up more than half the extra bits leftover after the formation of the sun and then used its gravity to clear out old comets and asteroids and maybe even old planets. Theorists contend Jupiter may have made space for Venus, Mars, Mercury and Earth to eventually form.

The probe will use microwave sounding to get a read on the amount of nitrogen in the form of ammonia, and oxygen in the form of water found on the planet. The probe will also be taking a gander at Jupiter's core. The planet's center is made of a core that gets hotter than the sun, but it's unclear what the core is composed of. Some believe it's a hunk of metal larger than Earth; others think it's a sea of high-pressure helium and hydrogen.

Juno will also check out the planet's incredibly strong magnetic field and the massive magnetosphere that juts hundreds of miles into space. The magnetic field is about 20,000 times more powerful than the one on Earth, and the magnetosphere stretches between 600,000 miles to 2 million miles from the sun, according to NASA. On the other end, the magnetosphere stretches all the way out to Saturn, about 600,000 miles away. The field traps charged particles and tugs them toward Jupiter, where they cause crazy powerful geomagnetic storms that light up Jupiter's poles with northern light displays that cover regions larger than the Earth. 

Juno will simply pass over the planet's poles — which may be easier said than done since this process has been likened to flying through the eye of a hurricane — measuring the strength of the magnetic field and the number of charged particles. By the time that flyby is done, NASA scientists should have more information about the processes that are behind space weather than they've ever had before. 

The project won't be a walk in the park. Jupiter can be pretty dicey because of its radiation levels alone. We're exposed to about .3 rad here on Earth, but during a series of low-altitude flyovers that will bring Juno within 3,100 miles of the edge of the clouds surrounding the planet, the probe will be hit with more than 20 million rad, as Gizmodo points out. Scientists have prepared for this by outfitting the whole system in an anti-radiation vault, the first one ever. All the scientific equipment has been placed in a titanium vault that cuts down radiation exposure to about 800 times less. Still, the craft will end up with radiation exposure just from being near the planet.

Scientists say they've prepared for the radiation issue and that they learned a lot from Galileo, the first probe sent to Jupiter back in the 1990s. Hopefully, they learned enough to make sure Juno gets into orbit and survives long enough to complete all of the missions.

But first Juno has to hit the right marks to get into Jupiter's orbit. On Monday there will be a 35-minute engine burn designed to slow the probe down from 150,000 mph to allow it to be pulled into Jupiter's orbit. If this doesn't go precisely right, the whole mission is off and all the money (roughly $1 billion) and time spent planning and waiting will have been for nothing.

Juno will subsequently circle around the planet, moving gradually closer until it sets itself up in October to be in the perfect orbiting position to collect scientific data the following month. In November the probe is scheduled to kick off a 33-week series of two-week flybys when most of the big research will be conducted.

About a year later, Juno will take the plunge into Jupiter's atmosphere, where its atoms will be scattered away, just like those of Galileo before it. After all, NASA scientists want to learn about Jupiter and that ever-so-promising moon, Europa, but they certainly don't want to be the kind of tourists who pollute. 

Of course, first things first, Juno has to get into orbit. We'll see if it all works out on Monday. 
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Dianna Wray is a nationally award-winning journalist. Born and raised in Houston, she writes about everything from NASA to oil to horse races.
Contact: Dianna Wray