ESA - Juice’s lunar-Earth flyby: all you need to know

<!doctype html> <html lang="en"> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0"> <link rel="stylesheet" type="text/css" href="/var/esa/cache/public/stylesheets/c35b41a32fb01cc5cc5a0efcc8ca483e_1685535780_all.css" /> <link href="/fontawesome/css/fontawesome.css" rel="stylesheet"> <link href="/fontawesome/css/brands.css" rel="stylesheet"> <link href="/fontawesome/css/solid.css" rel="stylesheet"> <script src="https://code.jquery.com/jquery-2.2.4.min.js" integrity="sha256-BbhdlvQf/xTY9gja0Dq3HiwQF8LaCRTXxZKRutelT44=" crossorigin="anonymous"></script> <script type="text/javascript" src="/var/esa/cache/public/javascript/ec3756e8a47adc0f64e3c43418bca85a_1729093166.js" charset="utf-8"></script> <meta property="og:title" content="Juice’s lunar-Earth flyby: all you need to know"> <title>ESA - Juice’s lunar-Earth flyby: all you need to know</title> <meta name="description" content="ESA’s Jupiter Icy Moons Explorer (Juice) will return to Earth on 19–20 August, with flight controllers guiding the spacecraft first past the Moon and then past Earth itself. 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This ‘braking’ manoeuvre will take Juice on a shortcut to Jupiter via Venus."> <meta name="keywords" content="LEGA, lunar-Earth flyby, lunar-Earth gravity assist, Juice, gravity assist manoeuvre, Jupiter Icy Moons Explorer"> <meta property="og:image" content="https://www.esa.int/var/esa/storage/images/esa_multimedia/images/2024/07/juice_flies_by_earth2/26253751-1-eng-GB/Juice_flies_by_Earth_pillars.png"> <meta name="twitter:card" content="summary_large_image"> <meta name="twitter:site" content="@esa"> <script> var _paq = window._paq = window._paq || []; _paq.push(["setDomains", ["*.www.esa.int","*.www.esa.int"]]); _paq.push(["enableCrossDomainLinking"]); _paq.push(['trackPageView']); _paq.push(['enableLinkTracking']); (function() { var u="https://www-analytics.esa.int/"; _paq.push(['setTrackerUrl', u+'matomo.php']); _paq.push(['setSiteId', '46']); var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0]; g.type='text/javascript'; g.async=true; g.src=u+'matomo.js'; s.parentNode.insertBefore(g,s);})(); </script> </head> <body> <div class="wrapper popmod"> <div id="cookie_loc"></div> <section id="esa-header" class="esa-header exploring-discovering"> <div class="esa-header__left"> <button id="esa-menu" class="esa-header__toggle menu-toggle"> <img class="esa-header__icon" src="/extension/pillars/design/pillars/images/ESA_Menu.svg" alt="ESA menu toggle"> </button> <button id="esa-search" class="esa-header__toggle search-toggle"> <img class="esa-header__icon" src="/extension/pillars/design/pillars/images/ESA_Search.svg" alt="ESA search toggle"> </button> <img class="esa-header__title" src="/extension/pillars/design/pillars/images/ESA_Title.svg" alt="ESA title"> </div> <div class="esa-header__right"> <a class="esa-header__link" href="/"> <img class="esa-header__logo" src="/extension/pillars/design/pillars/images/ESA_Logo.svg" alt="ESA logo"> </a> </div> </section> <form class="quick-search" action="/esearch"> <input class="quick-search__field" type="text" name="q" placeholder="Search ESA"> <button class="quick-search__submit" type="submit"><i class="far fa-arrow-right"></i></button> </form> <script> try { iniframe = window.self !== window.top;} catch (e) { iniframe = true;}if (!iniframe) {theme = 'exploring-discovering'; $.get('/var/esa/storage/menu_overlay.html', for_overlay_menu);}</script> <section id="overlay-menu"></section> <script> $.post( '/ezjscore/call', "ezjscServer_function_arguments=esaux::viewsincr::499670", function(data) { $(document).ready(function() { $('#viewcount').text(data) }) }) </script> <section class="feature feature--article"> <a href="/ESA_Multimedia/Images/2024/07/Juice_flies_by_Earth2" class="popup"> <img class="image-bg stellar" src="/var/esa/storage/images/esa_multimedia/images/2024/07/juice_flies_by_earth2/26253751-1-eng-GB/Juice_flies_by_Earth_pillars.png" alt="Juice flies by Earth" data-stellar-ratio="0.7" data-stellar-vertical-offset="60"> </a> </section> <article class="article exploring-discovering"> <header class="entry article__block"> <span class="pillar article__item">Science & Exploration</span> <h1 class="heading heading--main article__item">Juice’s lunar-Earth flyby: all you need to know</h1> <div class="meta article__item"> <span>15/07/2024</span> <span><span id="viewcount">25340</span><small> views</small></span> <span><span id="ezsr_total_26226428">128</span><small> likes</small></span> </div> </header> <div class="breadcrumbs article__block article__item"> <a class="breadcrumbs__entry" href="/">ESA</a> / <a class="breadcrumbs__entry" href="/Science_Exploration">Science & Exploration</a> / <a class="breadcrumbs__entry" href="/Science_Exploration/Space_Science">Space Science</a> / <a class="breadcrumbs__entry" href="/Science_Exploration/Space_Science/Juice">Juice</a></div> <div class="abstract article__block article__item"> <p>ESA’s Jupiter Icy Moons Explorer (Juice) will return to Earth on 19–20 August, with flight controllers guiding the spacecraft first past the Moon and then past Earth itself. This ‘braking’ manoeuvre will take Juice on a shortcut to Jupiter via Venus.</p> </div> <div class="article__block"> <h2 class="heading">What is happening?</h2> <p>It’s a double world first. The first-ever lunar-Earth flyby, and the first-ever double gravity assist manoeuvre. It will change Juice’s speed and direction to alter its course through space, but it’s a daring feat; the slightest mistake could take Juice off course and spell the end of the mission.</p><p>Following Juice’s <a href="https://www.esa.int/Science_Exploration/Space_Science/Juice/ESA_s_Juice_lifts_off_on_quest_to_discover_secrets_of_Jupiter_s_icy_moons">launch in April 2023</a>, this lunar-Earth flyby is the first step in the spacecraft’s waltz through the Solar System on its journey to Jupiter.</p><p>During the flyby, Earth will bend Juice’s trajectory through space, ‘braking’ it and redirecting it on course for a flyby of Venus in August 2025. From that moment on, the energy boosts will begin, with Juice being whizzed up by Venus and then twice by Earth – the space exploration equivalent of drinking three back-to-back espressos.</p> </div> <div class="feature slider"><div class="flexslider"><ul class="slides"> <li><div class="feature-item image"><figure class="thumbnail"><a href="/ESA_Multimedia/Images/2024/07/Juice_s_journey_to_Jupiter_the_lunar-Earth_flyby" class="popup"> <img class="image-bg" src="/var/esa/storage/images/esa_multimedia/images/2024/07/juice_s_journey_to_jupiter_the_lunar-earth_flyby/26229251-1-eng-GB/Juice_s_journey_to_Jupiter_the_lunar-Earth_flyby_pillars.jpg" alt="Juice's journey to Jupiter: the lunar-Earth flyby"> <figcaption class="image__caption">Juice's journey to Jupiter: the lunar-Earth flyby</figcaption> </a></figure></div></li> <li><div class="feature-item image"><figure class="thumbnail"><a href="/ESA_Multimedia/Images/2024/07/Juice_s_lunar-Earth_flyby_the_complete_path" class="popup"> <img class="image-bg" src="/var/esa/storage/images/esa_multimedia/images/2024/07/juice_s_lunar-earth_flyby_the_complete_path/26229298-1-eng-GB/Juice_s_lunar-Earth_flyby_the_complete_path_pillars.jpg" alt="Juice's lunar-Earth flyby: the complete path"> <figcaption class="image__caption">Juice's lunar-Earth flyby: the complete path</figcaption> </a></figure></div></li> <li><div class="feature-item image"><figure class="thumbnail"><a href="/ESA_Multimedia/Images/2024/07/Juice_s_lunar-Earth_flyby_step_I_the_Moon" class="popup"> <img class="image-bg" src="/var/esa/storage/images/esa_multimedia/images/2024/07/juice_s_lunar-earth_flyby_step_i_the_moon/26229345-5-eng-GB/Juice_s_lunar-Earth_flyby_step_I_the_Moon_pillars.png" alt="Juice's lunar-Earth flyby: step I, the Moon"> <figcaption class="image__caption">Juice's lunar-Earth flyby: step I, the Moon</figcaption> </a></figure></div></li> <li><div class="feature-item image"><figure class="thumbnail"><a href="/ESA_Multimedia/Images/2024/07/Juice_s_lunar-Earth_flyby_step_II_Earth" class="popup"> <img class="image-bg" src="/var/esa/storage/images/esa_multimedia/images/2024/07/juice_s_lunar-earth_flyby_step_ii_earth/26229392-5-eng-GB/Juice_s_lunar-Earth_flyby_step_II_Earth_pillars.png" alt="Juice's lunar-Earth flyby: step II, Earth"> <figcaption class="image__caption">Juice's lunar-Earth flyby: step II, Earth</figcaption> </a></figure></div></li> </ul></div></div> <div class="article__block"> <h2 class="heading">Why does it need to happen?</h2> <p>Jupiter is on average ‘just’ 800 million km away from Earth. Without an enormous rocket, sending Juice straight to the giant planet would require an impossible 60 000 kg of onboard propellant. And then Juice would need to be carrying an enormous additional amount of propellant to slow itself down enough to go into orbit around Jupiter once it arrives, rather than simply zipping straight past and off into outer space.</p><p>So Juice is taking the scenic route, using the gravity of other planets to carefully adjust its trajectory through space and ensure it arrives at Jupiter with the right speed and direction. This incredibly complex, constantly evolving route has been carefully planned out by Juice’s dedicated mission analysis team over the last 20 years.</p><p>Somewhat counterintuitively, using the lunar-Earth flyby to slow Juice down at this point in its journey is actually more efficient than using the flyby to speed it up. If we had instead used this flyby to give Juice a boost towards Mars, we would have had to wait a long time for the next planetary flyby. This first ‘braking’ manoeuvre is a way of taking a shortcut through the inner Solar System.</p><p><a href="https://www.esa.int/Enabling_Support/Operations/Juice_why_s_it_taking_sooo_long">Find out more about why Juice’s journey to Jupiter is so long and complex</a></p> </div> <div class="article__block"> <figure class="article__image article__image--large"> <a href="/ESA_Multimedia/Images/2024/07/Juice_s_journey_to_Jupiter_the_lunar-Earth_flyby" class="popup"> <img src="/var/esa/storage/images/esa_multimedia/images/2024/07/juice_s_journey_to_jupiter_the_lunar-earth_flyby/26229251-1-eng-GB/Juice_s_journey_to_Jupiter_the_lunar-Earth_flyby_article.jpg" alt=""> </a> <figcaption class="image__caption"> </figcaption> </figure> </div> <div class="article__block"> <h2 class="heading">How are we making it happen?</h2> <p>Mission operators have already <a href="https://www.esa.int/Enabling_Support/Operations/Juice_burns_hard_towards_first-ever_Earth-Moon_flyby">adjusted Juice’s path</a> to ensure that it arrives first at the Moon, then a day later at Earth, at precisely the right time, with the right speed, and travelling in the right direction. They are confident of success, but this is a risky challenge that no other space mission has ever faced before.</p><p>As Juice’s Spacecraft Operations Manager, Ignacio Tanco puts it: “It’s like passing through a very narrow corridor, very, very quickly: pushing the accelerator to the maximum when the margin at the side of the road is just millimetres.”</p><p>Juice will come extremely close to both the Moon and Earth, meaning that real-time pinpoint accuracy is required in all navigation manoeuvres. From 17–22 August, Juice will be in continuous contact with ground stations around the world. Every second of the way, through day and night, operators will keep a careful watch on the data coming down from Juice, making any tiny adjustments needed to keep the spacecraft on the right course.</p> </div> <div class="article__block"> <div class="article__video"> <a href="/ESA_Multimedia/Videos/2024/07/Juice_returns_for_a_lunar-Earth_flyby" class="popup"> <div class="video__wrapper"> <img class="play-button" src="/extension/pillars/design/pillars/images/play-button.svg" alt="Play"> <div class="dimmer"></div> <img class="image-bg" src="/var/esa/storage/images/esa_multimedia/videos/2024/07/juice_returns_for_a_lunar-earth_flyby/26253956-2-eng-GB/Juice_returns_for_a_lunar-Earth_flyby_pillars.jpg" alt="$video.data_map.short_description.content"> </div> </a> <div class="video__caption"> Juice returns for a lunar-Earth flyby <br><a href="/ESA_Multimedia/Videos/2024/07/Juice_returns_for_a_lunar-Earth_flyby" class="access-the-video popup">Access the video</a> </div> </div> </div> <div class="article__block"> <h2 class="heading">Bonus science!</h2> <p>As if steering Juice around two enormous space obstacles wasn’t enough, ESA will also be activating the spacecraft’s ten science instruments as it passes by the Moon and Earth.</p><p>The lunar-Earth flyby provides a prime test environment for instrument teams to collect and analyse data from an actual surface in space for the first time. For some instruments, this is the only opportunity to make certain measurements during Juice’s entire eight-year journey to Jupiter. It will give scientists and engineers the chance to calibrate their instruments, smooth out any remaining issues, and who knows, they may even make some surprising scientific discoveries.</p><p>The lunar-Earth flyby is particularly crucial for Juice’s Radar for Icy Moon Exploration (RIME) instrument, as RIME data is being disturbed by some electronic noise within the spacecraft.</p><p>The flyby of the Moon on 19 August is one of only a few chances before arrival at Jupiter for the RIME team to check how this noise is affecting the instrument’s performance. During the closest approach to the Moon, RIME will have eight minutes to observe alone, with the other instruments either switched off or set to quiet mode. Based on these observations, the RIME team will work on an algorithm to correct the noise problem.</p> </div> <div class="article__block"> <figure class="article__image article__image--large"> <a href="/ESA_Multimedia/Images/2022/12/Juice_s_science_instruments" class="popup"> <img src="/var/esa/storage/images/esa_multimedia/images/2022/12/juice_s_science_instruments/24640648-2-eng-GB/Juice_s_science_instruments_article.png" alt=""> </a> <figcaption class="image__caption"> </figcaption> </figure> </div> <div class="article__block"> <h2 class="heading">How can you follow along?</h2> <p><a href="https://blogs.esa.int/rocketscience/2024/08/19/join-us-live-as-juice-flies-past-the-moon/">Join us live</a> for Juice's flyby of the Moon at 23:30 CEST on 19 August.</p><p>A lucky few may even be able to see Juice pass overhead, with the spacecraft flying directly over Southeast Asia and the Pacific Ocean. Powerful binoculars or a telescope will give you the best chance of seeing the spacecraft. Trajectory data can be found <a href="https://www.cosmos.esa.int/web/spice/spice-for-juice">here</a>.</p><p>Meanwhile, Juice’s two <a href="https://www.esa.int/ESA_Multimedia/Images/2023/05/A_guide_to_Juice_s_monitoring_cameras">onboard monitoring cameras</a> will be snapping photos throughout the lunar-Earth flyby, which we will be sharing publicly via social media and our <a href="https://blogs.esa.int/rocketscience/">Rocket Science blog</a> as soon as they are received on Earth.</p><p>Follow <a href="https://twitter.com/ESA_JUICE">@ESA_Juice</a> and <a href="https://twitter.com/esaoperations/">@esaoperations</a> on X for the latest updates.</p><p>Find the media kit <a href="https://www.esa.int/Science_Exploration/Space_Science/Juice/Juice_lunar-Earth_flyby_media_kit">here</a>.</p> </div> <div class="share button-group article__block article__item"> <button id="ezsr_26226428_8_5" class="btn ezsr-star-rating-enabled" title="Like">Like</button> <p id="ezsr_just_rated_26226428" 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ESA - Juice’s lunar-Earth flyby: all you need to know