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\t\t\t\t\t\t28\/09\/2026<\/span> The European Space Agency\u2019s Jupiter Icy Moons Explorer (Juice) skimmed the very outer edge of Earth\u2019s atmosphere on 28 September, using the gravity of our home planet to alter its route to Jupiter using very little fuel.<\/p>\n<\/div>\n The flyby deflected Juice by an angle of 20\u00b0 compared to its pre-flyby path and increased its velocity by 3.5 km\/s. In the four weeks before the flyby, spacecraft operators only had to give Juice one tiny nudge (out of six opportunities set aside)\u00a0to put it on exactly the right approach trajectory to make the most of Earth\u2019s gravity. They have been tracking the spacecraft extra carefully since 17 August, and will continue to do so until 10 October.<\/p>\n Juice\u2019s closest approach was at 13:45 CEST (11:45 UTC) on 28 September. As Juice flew just 8640 km above the Indian Ocean, it snapped a series of images with its onboard monitoring cameras.<\/p>\n<\/p><\/div>\n \u201cThe flyby required ultra-precise navigation in real time. Thanks to our very careful planning, we used only a small amount of the propellant reserved for this flyby,\u201d says Angela Dietz, Juice\u2019s Spacecraft Operations Manager. \u201cThis gives us more to use at Jupiter to carry out observations of the planet\u2019s icy moons.\u201d<\/p>\n<\/p><\/div>\n While the main goal was to alter Juice\u2019s trajectory, the flyby also provided a third opportunity to test out Juice\u2019s science instruments on a real surface in space \u2013 with the first being during the spacecraft\u2019s 2024 lunar-Earth gravity assist, and the second during the 2025 observations of Comet 3I\/ATLAS.<\/p>\n Colleagues from ESA’s spacecraft operations, science operations and technical centres spent months working hard with the external teams working on Juice’s 10 science instruments to plan which instruments to switch on and when. Thanks to their efforts, the team has been able to squeeze out as much operational time as possible considering tight spacecraft resources.<\/p>\n \u201cJuice’s journey to Jupiter provides only a few opportunities to calibrate and validate the instruments under well-understood environmental conditions,\u201d explains Juice project scientist Claire Vallat, who led the effort.<\/p>\n \u201cGiven the limited time available and operational constraints, instrument activities sometimes have to be prioritised, for example when Juice was in Earth’s shadow this morning, and relying on battery power alone. During this flyby, calibration activities were prioritised based on their relevance to preparing the instruments for their work at Jupiter, while also considering whether an opportunity is unique or can be scheduled later in the journey.\u201d<\/p>\n It\u2019s been a lot of work, but an Earth flyby is actually relatively straightforward compared to Juice\u2019s upcoming 35 flybys of Jupiter\u2019s giant moons Ganymede, Europa and Ganymede. For the Europa flybys, for example, discussions on instrument operations started 10 years ago and will continue until Juice flies past Europa in the early 2030s.<\/p>\n The Earth flyby is a great opportunity to calibrate instruments, figure out how best to work with them in space (where they always work a little differently to on Earth!), and develop data analysis tools. But the icy moon flybys will be the real deal, and Juice needs to be ready to collect the best possible scientific data.<\/p>\n During the Earth flyby, Juice spent several days flying through the magnetotail \u2013 the part of Earth\u2019s magnetic field that stretches out away from the Sun. This has provided an excellent opportunity to measure magnetic fields and charged particles far from our planet. Meanwhile, the European-Chinese Smile mission has been watching the northern lights and measuring magnetic fields and particles close to Earth. Together, Juice and Smile’s observations provide a unique opportunity to connect activity in the distant magnetotail with what is happening at Earth’s poles.<\/p>\n We expect to publish images and spectra collected by some of Juice\u2019s instruments in the coming weeks, after they have arrived on Earth and been evaluated by the teams of scientists working on the instruments. This includes high-resolution images of the Moon and Earth from Juice\u2019s scientific camera, JANUS.<\/p>\n In January 2029, Juice will meet Earth one last time, coming back for a third flyby of our home planet to put it onto the final track to meet Jupiter in 2031.<\/p>\n<\/p><\/div>\n About Juice<\/i><\/b><\/p>\n ESA\u2019s Jupiter Icy Moons Explorer, \u2018Juice\u2019, is humankind\u2019s next bold mission to the outer Solar System. It will make detailed observations of gas giant Jupiter and its three large ocean-bearing moons \u2013 Ganymede, Callisto and Europa. This ambitious mission will characterise these moons with a powerful suite of remote sensing, geophysical and in situ instruments to discover more about these compelling destinations as potential habitats for past or present life.<\/i><\/p>\n Juice will monitor Jupiter\u2019s complex magnetic, radiation and plasma environment in depth and its interplay with the moons, studying the Jupiter system as an archetype for gas giant systems across the Universe.<\/i><\/p>\n Juice launched on an Ariane 5 from Europe\u2019s Spaceport in Kourou in April 2023. It has an eight-year cruise with flybys of Earth and Venus to slingshot it to Jupiter. It will make 35 flybys of the three large moons while orbiting Jupiter, before changing orbits to Ganymede.<\/i><\/p>\n Juice is a mission under ESA leadership with contributions from NASA, JAXA and the Israel Space Agency. It is the first Large-class mission in ESA\u2019s\u00a0<\/i>Cosmic Vision programme<\/i>.<\/i><\/p>\n \u00a0<\/i><\/p>\n For more information, please contact ESA Media Relations:<\/i><\/b><\/p>\n media@esa.int<\/i><\/p>\n<\/p><\/div>\n
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\n\t\t\t\t\t\t\t\t<\/figcaption><\/figure>\nEarth as a testbench<\/b><\/h3>\n
Next stop: one last hello to Earth<\/b><\/h3>\n