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\t\t\t\t\t\t17\/11\/2023<\/span> On 17 November 2023, ESA\u2019s Juice spacecraft carried out one of the largest and most important manoeuvres in its eight-year journey to Jupiter.<\/p>\n Using its main engine, Juice changed its orbit around the Sun to put itself on the correct trajectory for next summer\u2019s Earth-Moon double gravity assist \u2013 the first of its kind.<\/p>\n The manoeuvre lasted 43 minutes and burned almost 10% of the spacecraft\u2019s entire fuel reserve. It\u2019s the first part of a two-part manoeuvre that could mark the final time that Juice\u2019s main engine is used until its arrival in the Jupiter system in 2031.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n ESA\u2019s Jupiter Icy Moons Explorer (Juice) launched from Europe\u2019s spaceport in French Guiana on 14 April 2023.<\/p>\n It\u2019s on a mission to make detailed observations of the giant gas planet and its three large, ocean-bearing moons \u2013 Ganymede, Callisto and Europa.<\/p>\n But Juice won\u2019t begin its investigations into the nature and possible habitability of the Jupiter system until its arrival in 2031.<\/p>\n Why does it take so long to get to Jupiter? Well, the short answer is that its less to do with the distance between Earth and Jupiter and more to do with fighting the Sun\u2019s massive gravitational pull as you venture outwards through the Solar System.<\/p>\n Missions to the giant gas planets, such as Juice, Europa Clipper, Galileo or Juno, would be little more than giant fuel tanks if they had to store all the energy needed to overcome the Sun\u2019s gravity by themselves.<\/p>\n Instead, they make use of \u2018gravity-assist\u2019 or \u2018flyby\u2019 manoeuvres to gain energy by swinging through the strong gravitational fields of various planets on the way.<\/p>\n<\/p><\/div>\n Juice\u2019s first boost will come from its home planet, when it returns to Earth in August 2024, more than one year after launch.<\/p>\n In fact, in a first-of-its-kind flyby, Juice will first pass by the Moon to give it an extra kick and make the flyby of Earth that takes place 1.5 days later even more effective.<\/p>\n But even with this extra boost, to get the most out of the gravity assist, Juice has to arrive at the Earth-Moon system at precisely the correct time, at the correct speed and travelling in the correct direction.<\/p>\n That\u2019s where today\u2019s manoeuvre comes in.<\/p>\n On 17 November, at 16:10 (CET), Juice\u2019s main engine performed a burn that lasted roughly 43 minutes.<\/p>\n<\/p><\/div>\n \u201cThis manoeuvre used up roughly 363 kg of fuel \u2013 or almost exactly 10% of the 3650kg of fuel that Juice launched with,\u201d says Julia Schwartz, Flight Dynamics Engineer at ESA\u2019s ESOC mission control centre in Germany.<\/p>\n This is Juice\u2019s largest manoeuvre so far. Until today, Juice had only used roughly 10 kg of fuel \u2013 mostly as part of a series of short burns used to help free its stuck RIME antenna.\u00a0<\/p>\n \u201cIt was the first part of a two-part manoeuvre to put Juice on the correct trajectory for next summer\u2019s encounter with Earth and the Moon. This first burn did 95% of the work, changing Juice\u2019s velocity by almost 200 m\/s,\u201d adds Julia.<\/p>\n \u201cJuice is one of the heaviest interplanetary spacecraft ever launched, with a total mass of around 6000 kg, so it took a lot of force and a lot of fuel to achieve this.\u201d<\/p>\n \u201cIn a few weeks, once we\u2019ve analysed Juice\u2019s new orbit, we will carry out the second, much smaller second part of the manoeuvre. Splitting the manoeuvre into two parts allows us to use the second firing of the engine to iron out any inaccuracies of the first.\u201d<\/p>\n An additional, much smaller manoeuvre using Juice\u2019s smaller thrusters may be carried out in May 2024 for the final fine tuning during the approach to Earth.<\/p>\n<\/p><\/div>\n For a mission on an eight-year journey, burning 10% of your fuel reserve in just 43 minutes may seem crazy. But investing all that fuel now will pay off for years to come.<\/p>\n \u201cIf all goes well with both parts of this manoeuvre, we likely won\u2019t need to use the main engine again until we enter orbit around Jupiter in 2031,\u201d says Ignacio Tanco, Juice Spacecraft Operations Manager. \u201cFor small trajectory corrections between now and then, we will use Juice\u2019s smaller thrusters.\u201d<\/p>\n But that doesn\u2019t mean nothing interesting will happen between now and Juice\u2019s arrival at Jupiter. Quite the opposite, the journey is interesting because<\/i> it allows Juice to get all the way to Jupiter without firing of its main engine again, reducing the amount of fuel the spacecraft needs and allowing it to be packed full of scientific instruments.<\/p>\n After the Earth-Moon double flyby of 2024 (knows as a Lunar-Earth Gravity Assist; LEGA), Juice will first make one flyby of Venus in 2025 and two further flybys of Earth in 2026 and 2029 (both without the additional boost from the Moon).<\/p>\n \u201cToday\u2019s manoeuvre will ensure Juice arrives at the Earth-Moon system at the right time next year for the double flyby,\u201d adds Ignacio.<\/p>\n \u201cAnd, thanks to the clever trajectory designed by our Mission Analysis team, that flyby will line it up almost perfectly for all of the others, without us having to fire the main engine again.\u201d<\/p>\n With each flyby, the spacecraft will gain more energy than could be achieved by burning a reasonable amount of fuel \u2013 energy that will help it climb towards Jupiter against the pull of the Sun\u2019s gravity.<\/p>\n<\/p><\/div>\n \u201cIt was very important that we carry out this manoeuvre today. Otherwise, the cost \u2013 how much fuel we would need to burn to reach the new orbit we need \u2013 would begin to shoot up dramatically,\u201d says Ignacio.<\/p>\n Today\u2019s burn also gave the teams the opportunity to make sure Juice\u2019s main engine is working correctly. It was first tested shortly after launch, but it until today, it hadn\u2019t been used for such a big manoeuvre out in deep space.<\/p>\n \u201cThere were some things that we couldn\u2019t test before now. For example, we only had an estimate for how the liquid in the fuel tanks will move around as the spacecraft accelerates. This is very important to know precisely, because if the fuel behaves different to how we expect, it could cause the spacecraft to drift off course during the burn. So, we are monitoring closely.\u201d<\/p>\n<\/p><\/div>\n The next time that Juice will absolutely have to fire its main engine is during its \u2018Jupiter Orbit Insertion\u2019 in 2031. This is the single most important manoeuvre that the teams at ESOC will oversee.<\/p>\n Just 13 hours after swinging by Ganymede and entering the Jupiter system, the spacecraft will need to slow down by about 1 km\/s \u2013 five times the change in velocity achieved today.<\/p>\n \u201cThat makes today\u2019s manoeuvre also an important test for Jupiter insertion \u2013 the sooner we know if we have any issues with the main engine, the better,\u201d says Ignacio.<\/p>\n Once in orbit around the gas giant, Juice can begin its exploration of the Jupiter system. Teams at ESOC will steer Juice through a series of 35 flybys of the ocean moons. Where once flybys were a yearly occurrence, at Jupiter they will be carried out as often as once every two weeks.<\/p>\n These close-ups of the icy moons will allow the spacecraft and scientists on Earth to gather the data needed to better understand these mysterious alien worlds.<\/p>\n<\/p><\/div>\n Want to know more about how Juice was imagined, designed, constructed and launched? The feature-length film, \u2018The Making of Juice\u2019, premieres on ESA\u2019s YouTube channel at 18:00 CET on 23 November 2023.<\/p>\n For regular updates on the mission, follow @ESA_JUICE<\/a>, @esaoperations<\/a> and @ESAJuiceBar<\/a> on X.<\/p>\n<\/p><\/div>\n
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\n\t\t\t\t\t\t\t\t\t\t17<\/span> likes<\/small><\/span><\/p>\n<\/header>\nIn brief<\/h2>\n
In-depth<\/h2>\n<\/div>\n
Mission to Jupiter picks up speed<\/h2>\n
\n\t\t\t\t\t\t\t\t<\/figcaption><\/figure>\nShooting for the Moon<\/h2>\n
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\n\t\t\t\t\t\t\t\t<\/figcaption><\/figure>\n<\/p><\/div>\nLast use of the main engine until 2031<\/h2>\n
\n\t\t\t\t\t\t\t\t<\/figcaption><\/figure>\nNext stop: Jupiter!<\/h2>\n
\n\t\t\t\t\t\t\t\t<\/figcaption><\/figure>\nJuice \u2013 up to date and behind the scenes<\/h2>\n