by NASA’s Juno mission will get closer to Jupiter’s moon Io than any spacecraft in about 20 years on Saturday (December 30).
The flyby will take Juno to within about 930 miles (1,500 kilometers) of Io, the most volcanic body in the solar system. This will allow the spacecraft to observe Io in detail while collecting a trove of interesting data. It’s close, but it’s not the closest view ever achieved by a spacecraft: That record belongs to NASA’s Galileo spacecraft, which skimmed just 181 kilometers (112 miles) over Io’s south pole in 2001.
Juno launched on August 5, 2011 and reached gas giant Jupiter, the largest planet in the solar system, on July 4, 2016, after a journey of 2.8 billion kilometers (1.7 billion kilometers). miles). Since then, the Jupiter orbiter has made 56 flybys of the gaseous planet, collecting data about it and its moons, and is about to begin the next.
“By combining data from this flyby with our previous observations, the Juno science team is studying how Io’s volcanoes vary,” Southwest Research Institute scientist and Juno principal investigator Scott Bolton said in a statement. “We’re looking at how often they erupt, how bright and hot they are, how the shape of the lava flow changes, and how Io’s activity is related to the flow of charged particles in Jupiter’s magnetosphere.”
Related: Jupiter’s moon Io is covered in active volcanoes. Now we have the first map of them.
Now in the third year of its extended mission, with its primary mission ending in July 2021, Juno will make another close flyby of Io on February 3, 2024, when it will be about 930 miles (1,500 km) from the volcano. surface of this Jovian world.
Flybys of Io in December 2023 and February 2024 will add to the wealth of information scientists have gathered about Io thanks to Juno, which has been monitoring its volcanic activity from distances ranging from 6,830 miles (11,000 km) to more than 62,100 miles. (100,000 kilometers). During its operation, NASA’s spacecraft has also provided researchers with the first views of Io’s north and south poles.
Why investigate Jupiter’s “tortured moon” Io?
The surface of Io, which is about the size of Earth’s moon, is dotted with hundreds of actively erupting volcanoes capable of spewing lava tens of kilometers into the Jovian moon’s thin, waterless atmosphere.
Jupiter’s innermost Galilean satellite, one of the four large Jovian moons, Io, is believed to be extremely volcanic due to the gravitational influence of the gas giant planet and that of its three other Galilean moons: Europa, Ganymede and Callisto.
This generates tidal forces that are so powerful that they can cause Io’s surface to rise and fall up to 330 feet (100 meters), causing extreme volcanism.
“With our pair of close flybys in December and February, Juno will investigate the source of Io’s massive volcanic activity, whether a magma ocean exists beneath its crust, and the importance of Jupiter’s tidal forces, which are relentlessly squeezing this tortured moon.” Bolton added.
Understanding Io’s volcanism is necessary because it likely has an impact on the Jovian system as a whole. For example, volcanic particles escaping Io’s atmosphere are thought to be trapped by Jupiter’s magnetic field, forming a donut of hot plasma around the gas giant planet.
How does Juno investigate Io?
During the Io flyby this weekend, all three of Juno’s cameras will be active. The Jovian Infrared Auroral Mapper (JIRAM) will collect information about the volcanic moon’s heat signature and locate volcanoes and calderas across the Jovian moon. Meanwhile, the star’s navigation camera, the Stellar Reference Unit, will collect the highest-resolution images of Io’s volcano-torn surface yet collected.
Last but not least, JunoCam, which is included in the Juno instrument suite to drive public engagement, will capture full-color visible-light images of the volcanic moon.
JunoCam was designed to last only eight flybys of Jupiter, making the images of Io it will collect during this 57th flyby even more remarkable. The three cameras and the Juno spacecraft itself have had to challenge and withstand the demanding radiation environment around Jupiter, possibly the harshest in the solar system except the sun, to continue this remarkable scientific mission. But this punishment has begun to be noticed.
“The cumulative effects of all that radiation have started to show up on JunoCam in the last few orbits,” said Juno project manager Ed Hirst. “Images from the latest flyby show a reduction in the camera’s dynamic range and the appearance of ‘streaky’ noise. Our engineering team has been working on solutions to alleviate radiation damage and keep the camera operational.”
After Juno’s orbit of Io in February 2024, NASA’s orbiter will brush past the Jovian moon on each of its subsequent orbits of Jupiter, but each of them will subsequently move away from Io’s volcanic surface.
The first flyby after February will take place at an altitude of about 16,500 kilometers (10,250 miles) above Io, while the last will take NASA’s spacecraft about 115,000 kilometers (71,450 miles) from the volcanic moon.
Juno will also now begin to experience periods during which Jupiter eclipses the sun, blocking its access to solar energy and leading it to experience darkness for the first time since it left Earth.
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This is not expected to affect Juno’s operation, and starting in April 2024, the spacecraft will use these occultation events to assist its gravity science experiment to investigate the composition of Jupiter’s upper atmosphere and gather information about the shape of the planet and its interior. structure.
Juno’s extended mission investigating the Jovian system will last until September 2025, when NASA says the spacecraft will reach the end of its life and will likely intentionally crash into the gas giant’s atmosphere.
