Swooping around Jupiter

The Juno spacecraft is orbiting Jupiter, returning a lot of science and images to NASA on Earth.

Sequence of Juno Spacecraft’s Close Approach to Jupiter

Juno telecon image

Image Credit: NASA/SWRI/MSSS/Gerald Eichstädt/Seán Doran

This sequence of enhanced-color images shows how quickly the viewing geometry changes for NASA’s Juno spacecraft as it swoops by Jupiter. The images were obtained by JunoCam.

Once every 53 days the Juno spacecraft swings close to Jupiter, speeding over its clouds. In just two hours, the spacecraft travels from a perch over Jupiter’s north pole through its closest approach (perijove), then passes over the south pole on its way back out.

The first image on the left shows the entire half-lit globe of Jupiter, with the north pole approximately in the center. As the spacecraft gets closer to Jupiter, the horizon moves in and the range of visible latitudes shrinks.

The third and fourth images in this sequence show the north polar region rotating away from our view while a band of wavy clouds at northern mid-latitudes comes into view.

By the fifth image of the sequence the band of turbulent clouds is nicely centered in the image.

The seventh and eighth images were taken just before the spacecraft was at its closest point to Jupiter, near Jupiter’s equator. Even though these two pictures were taken just four minutes apart, the view is changing quickly.

As the spacecraft crossed into the southern hemisphere, the bright “south tropical zone” dominates the ninth, 10th and 11th images.

The white ovals in a feature nicknamed Jupiter’s “String of Pearls” are visible in the 12th and 13th images.

In the 14th image Juno views Jupiter’s south poles.

An animated close encounter with Jupiter:

NASA / SwRI / MSSS / Gerald Eichstädt / Seán Doran

Music by Ligeti

A Whole New Jupiter: First Science Results from NASA’s Juno Mission

Early science results from NASA’s Juno mission to Jupiter portray the largest planet in our solar system as a complex, gigantic, turbulent world, with Earth-sized polar cyclones, plunging storm systems that travel deep into the heart of the gas giant, and a mammoth, lumpy magnetic field that may indicate it was generated closer to the planet’s surface than previously thought.

Juno launched on Aug. 5, 2011, entering Jupiter’s orbit on July 4, 2016. The findings from the first data-collection pass, which flew within about 2,600 miles (4,200 kilometers) of Jupiter’s swirling cloud tops on Aug. 27, are being published this week in two papers in the journal Science, as well as 44 papers in Geophysical Research Letters.

Among the findings that challenge assumptions are those provided by Juno’s imager, JunoCam. The images show both of Jupiter’s poles are covered in Earth-sized swirling storms that are densely clustered and rubbing together.

We’re puzzled as to how they could be formed, how stable the configuration is, and why Jupiter’s north pole doesn’t look like the south pole,” said Bolton. “We’re questioning whether this is a dynamic system, and are we seeing just one stage, and over the next year, we’re going to watch it disappear, or is this a stable configuration and these storms are circulating around one another?”

Another surprise comes from Juno’s Microwave Radiometer (MWR), which samples the thermal microwave radiation from Jupiter’s atmosphere, from the top of the ammonia clouds to deep within its atmosphere. The MWR data indicates that Jupiter’s iconic belts and zones are mysterious, with the belt near the equator penetrating all the way down, while the belts and zones at other latitudes seem to evolve to other structures. The data suggest the ammonia is quite variable and continues to increase as far down as we can see with MWR, which is a few hundred miles or kilometers.

Prior to the Juno mission, it was known that Jupiter had the most intense magnetic field in the solar system. Measurements of the massive planet’s magnetosphere, from Juno’s magnetometer investigation (MAG), indicate that Jupiter’s magnetic field is even stronger than models expected, and more irregular in shape. MAG data indicates the magnetic field greatly exceeded expectations at 7.766 Gauss, about 10 times stronger than the strongest magnetic field found on Earth.

“Juno is giving us a view of the magnetic field close to Jupiter that we’ve never had before,” said Jack Connerney, Juno deputy principal investigator and the lead for the mission’s magnetic field investigation at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Already we see that the magnetic field looks lumpy: it is stronger in some places and weaker in others. This uneven distribution suggests that the field might be generated by dynamo action closer to the surface, above the layer of metallic hydrogen. Every flyby we execute gets us closer to determining where and how Jupiter’s dynamo works.”

Juno also is designed to study the polar magnetosphere and the origin of Jupiter’s powerful auroras—its northern and southern lights. These auroral emissions are caused by particles that pick up energy, slamming into atmospheric molecules. Juno’s initial observations indicate that the process seems to work differently at Jupiter than at Earth.

Juno is in a polar orbit around Jupiter, and the majority of each orbit is spent well away from the gas giant. But, once every 53 days, its trajectory approaches Jupiter from above its north pole, where it begins a two-hour transit (from pole to pole) flying north to south with its eight science instruments collecting data and its JunoCam public outreach camera snapping pictures. The download of six megabytes of data collected during the transit can take 1.5 days.

“Every 53 days, we go screaming by Jupiter, get doused by a fire hose of Jovian science, and there is always something new,” said Bolton. “On our next flyby on July 11, we will fly directly over one of the most iconic features in the entire solar system — one that every school kid knows — Jupiter’s Great Red Spot. If anybody is going to get to the bottom of what is going on below those mammoth swirling crimson cloud tops, it’s Juno and her cloud-piercing science instruments.”

More information on the Juno mission is available at:

https://www.nasa.gov/juno

http://missionjuno.org

2 Comments

  1. Gezza

     /  June 3, 2017

    Thanks for that post PG. 👍 Fascinating stuff for me. That video clip full screen is stunning.

  2. Brown

     /  June 3, 2017

    Its a bit like my first wife – nice to look at from a distance but incredibly hostile up close.