NASA’s Juno deep space probe has made a close flyby of Jupiter’s unstable moon Io, its first close encounter with Jupiter. During its 51st orbit around the giant planet, the solar-powered robotic spacecraft came within 22,600 miles (35,500 kilometers) of the surface of Io’s volcano.
Juno launched for the first time on Aug. 5, 2011, on an Atlas V rocket from what is now Space Force in Cape Canaveral, Florida, beginning a seven-year mission that is now in its 12th years. On July 5, 2016, it entered orbit around Jupiter and has traveled more than 510 million miles (820 million kilometers) to date.
Even so, Juno completed only 50 orbits of Jupiter. That’s because its trajectory carries it far away from Earth in a very long arc, taking weeks at a time. This allows the spacecraft to observe Jupiter and its moons from different vantage points and minimizes damage to spacecraft systems through Jupiter’s deadly radiation belts.
During the latest flyby, NASA scientists were keen to collect new data — both to help plan future missions and to learn more about the most volcanically active body in the solar system. Even though it’s smaller than Earth’s moon, Io has a molten interior and sulfur-spewing volcanoes that erupt with startling regularity. That’s because it orbits close to Jupiter, and the giant planet’s tidal forces constantly pull on Io, energizing its geology.
During the encounter on May 15, 2023, Juno will not only use its JunoCam to take pictures, but will also use its Jupiter Infrared Auroral Mapper (JIRAM), Stellar Reference Unit (SRU) and Microwave Radiometer (MWR) to take readings, To observe the moon’s volcanoes and magnetosphere.
Scott Bolton, Juno principal investigator at the Southwest Research Institute in San Antonio, said: “Io is the most volcanic object in the solar system that we know of. By observing it many times, we can see how the volcanoes change — they erupt. How often, how bright and hot they are, whether they erupt in groups or individually, and whether the shape of the lava flow changes.
“We’re entering another amazing part of the Juno mission as we get closer to a continuous orbit around Io. The 51st orbit will give us an up-close look at the tormented moon. We’ll be in the The July and October flybys will bring us even closer, leading to our double flyby encounters with Io this December and next February, when we flew within 1,500 kilometers (930 miles) of its surface. All of these flybys provide Spectacular view of volcanic activity on this amazing moon. The data should be stunning.