The Jupiter Icy Moons Explorer (Juice, formerly JUICE) is an interplanetary spacecraft on its way to orbit and study three

icy moon Icy moons are a class of natural satellites with surfaces composed mostly of ice. An icy moon may harbor an ocean underneath the surface, and possibly include a rocky core of silicate or metallic rocks. It is thought that they may be composed of i ...

s of

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined a ...

: Ganymede,

Callisto CALLISTO (''Cooperative Action Leading to Launcher Innovation in Stage Toss-back Operations'') is a reusable VTVL Prototype, demonstrator propelled by a small 40 kN Japanese LOX-LH2 rocket engine. It is being developed jointly by the CNES, French ...

, and Europa. These planetary-mass moons are planned to be studied because they are thought to have significant bodies of liquid water beneath their frozen surfaces, which would make them potentially habitable for

extraterrestrial life Extraterrestrial life, or alien life (colloquially, aliens), is life that originates from another world rather than on Earth. No extraterrestrial life has yet been scientifically conclusively detected. Such life might range from simple forms ...

. Juice is the first interplanetary spacecraft to the outer Solar System planets not launched by the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

and the first set to orbit a moon other than Earth's

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

. Launched by the

European Space Agency The European Space Agency (ESA) is a 23-member International organization, international organization devoted to space exploration. With its headquarters in Paris and a staff of around 2,547 people globally as of 2023, ESA was founded in 1975 ...

(ESA), from

Guiana Space Centre The Guiana Space Centre (; CSG), also called Europe's Spaceport, is a spaceport to the northwest of Kourou in French Guiana, an Overseas departments and regions of France, overseas region of France in South America. Kourou is located approxim ...

French Guiana French Guiana, or Guyane in French, is an Overseas departments and regions of France, overseas department and region of France located on the northern coast of South America in the Guianas and the West Indies. Bordered by Suriname to the west ...

on 14 April 2023, with

Airbus Defence and Space Airbus Defence and Space is a division of Airbus SE. Formed in 2014 in the restructuring of European Aeronautic Defence and Space (EADS), Airbus SE comprises the former Airbus Military, Astrium, and divisions. Contributing 21% of Airbus reven ...

as the main contractor, it is expected to reach Jupiter in July 2031 after four

gravity assist A gravity assist, gravity assist maneuver, swing-by, or generally a gravitational slingshot in orbital mechanics, is a type of spaceflight flyby (spaceflight), flyby which makes use of the relative movement (e.g. orbit around the Sun) and gra ...

s and eight years of travel. In December 2034, the spacecraft will enter orbit around Ganymede for its close-up science mission. Its period of operations will overlap with

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

's ''

Europa Clipper Europa Clipper (previously known as Europa Multiple Flyby Mission) is a space probe developed by NASA to study Europa (moon), Europa, a Galilean moon of Jupiter. It was launched on October 14, 2024. The spacecraft used a gravity assist from Mar ...

'' mission, which was launched in October 2024.

Background

The mission started as a reformulation of the Jupiter Ganymede Orbiter proposal, which was to be ESA's component of the cancelled Europa Jupiter System Mission – Laplace (EJSM-Laplace). It became a candidate for the first L-class mission (L1) of the ESA

Cosmic Vision Cosmic Vision is the third campaign of space science and space exploration missions in the Science Programme of the European Space Agency (ESA). Formulated in 2005 as ''Cosmic Vision: Space Science for Europe 2015–2025'', the campaign succee ...

Programme, and its selection was announced on 2 May 2012. In April 2012, Juice was recommended over the proposed Advanced Telescope for High Energy Astrophysics (ATHENA) X-ray telescope and a

gravitational wave Gravitational waves are oscillations of the gravitational field that Wave propagation, travel through space at the speed of light; they are generated by the relative motion of gravity, gravitating masses. They were proposed by Oliver Heaviside i ...

observatory ( New Gravitational wave Observatory (NGO)). In July 2015,

was selected as the prime contractor to design and build the probe, to be assembled in

Toulouse Toulouse (, ; ; ) is a city in southern France, the Prefectures in France, prefecture of the Haute-Garonne department and of the Occitania (administrative region), Occitania region. The city is on the banks of the Garonne, River Garonne, from ...

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

. By 2023, the mission was estimated to cost ESA 1.5 billion euros ($1.6 billion).

Spacecraft

JUICE inside Airbus Defence and Space Astrolabe facilities 08

The main spacecraft design drivers are related to the large distance to the Sun, the use of

solar power Solar power, also known as solar electricity, is the conversion of energy from sunlight into electricity, either directly using photovoltaics (PV) or indirectly using concentrated solar power. Solar panels use the photovoltaic effect to c ...

, and Jupiter's harsh radiation environment. The orbit insertions at Jupiter and Ganymede and the large number of flyby manoeuvres (more than 25

s, and two Europa flybys) require the spacecraft to carry about of chemical propellant. The total

delta-V Delta-''v'' (also known as "change in velocity"), symbolized as and pronounced , as used in spacecraft flight dynamics, is a measure of the impulse per unit of spacecraft mass that is needed to perform a maneuver such as launching from or l ...

capability of the spacecraft is about . Juice has a fixed 2.5 meter diameter high-gain antenna and a steerable medium-gain antenna; both X- and K-band will be used. Downlink rates of 2 Gb/day are possible with ground-based Deep Space Antennas. On-board data storage capability is 1.25 Tb. The Juice main engine is a hypergolic bi-propellant ( mono-methyl hydrazine and

mixed oxides of nitrogen Mixed oxides of nitrogen (MON) are solutions of dinitrogen trioxide (N2O3) in dinitrogen tetroxide/nitrogen dioxide (N2O4 and NO2). It may be used as an oxidizing agent in rocket propulsion systems. Mixed oxides of nitrogen are produced by disso ...

) 425 N thruster. A 100 kg multilayer insulation provides thermal control. The spacecraft is 3-axis stabilized using

momentum wheel A reaction wheel (RW) is an electric motor attached to a flywheel, which, when its rotation speed is changed, causes a counter-rotation proportionately through Angular momentum#Conservation of angular momentum, conservation of angular momentum. ...

s. Radiation shielding is used to protect onboard electronics from the Jovian environment (the required radiation tolerance is 50 kilorad at equipment level). The Juice science payload has a mass of and includes the JANUS camera system, the MAJIS visible and infrared imaging spectrometer, the UVS ultraviolet imaging spectrograph, RIME radar sounder, GALA laser altimeter, SWI submillimetre wave instrument, J-MAG magnetometer, PEP particle and plasma package, RPWI radio and plasma wave investigation, 3GM radio science package, the PRIDE radio science instrument, and the RADEM radiation monitor. A deployable boom will hold J-MAG and RPWI, a long deployable antenna will be used for RIME. Four booms carry parts of the RPWI instrument. The other instruments are mounted on the spacecraft body, or for 3GM, within the spacecraft bus.

Timeline

Launch

Juice was launched into space on 14 April 2023 from the

on an

Ariane 5 Ariane 5 is a retired European heavy-lift space launch vehicle operated by Arianespace for the European Space Agency (ESA). It was launched from the Guiana Space Centre (CSG) in French Guiana. It was used to deliver payloads into geostationar ...

rocket. This was the final launch of an ESA science mission using the Ariane 5 vehicle, and was the second to last launch of the rocket overall. The launch was originally scheduled for 13 April 2023, but due to poor weather the launch was postponed. The next day a second launch attempt succeeded, with liftoff occurring at 12:14:36 UTC. After the spacecraft separated from the rocket, it established a successful radio signal connection with the ground at 13:04 UTC. Juice's solar arrays were deployed about half an hour later, prompting ESA to deem the launch a success.

Trajectory

Following the launch, there will be multiple planned

s to put Juice on a trajectory to Jupiter: * A flyby of the Earth–Moon system in August 2024 * Venus flyby in August 2025 * Second flyby of Earth in September 2026 * A third and final flyby of Earth in January 2029 Juice will pass through the

asteroid belt The asteroid belt is a torus-shaped region in the Solar System, centered on the Sun and roughly spanning the space between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies called asteroids ...

twice. A flyby of the asteroid 223 Rosa was proposed to occur in October 2029, but was abandoned to save fuel for the primary Jovian mission. Gravity assists include: * Interplanetary transfer (Earth, Venus, Earth, Earth) * Jupiter orbit insertion and apocentre reduction with multiple Ganymede gravity assists * Reduction of velocity with Ganymede–Callisto assists * Increase

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Eart ...

with 10–12 Callisto gravity assists

Summary of intended Jupiter mission phases

The main characteristics of the Jupiter reference tour are summarised below (source: Table 5-2 of ESA/SRE(2014)1). This scenario assumed an early June 2022 launch, however, the

requirements are representative due to the rather short, repetitive orbital configurations of Europa, Ganymede and Callisto.

Science objectives

The Juice orbiter will perform detailed investigations on Ganymede and evaluate its potential to support life. Investigations of Europa and

will complete a comparative picture of these

Galilean moons The Galilean moons (), or Galilean satellites, are the four largest moons of Jupiter. They are, in descending-size order, Ganymede (moon), Ganymede, Callisto (moon), Callisto, Io (moon), Io, and Europa (moon), Europa. They are the most apparent m ...

. The three moons are thought to harbour internal liquid water oceans, and so are central to understanding the

habitability Habitability is the adequacy of an environment for human living. Where housing is concerned, there are generally local ordinances which define habitability. If a residence complies with those laws, it is said to be habitable. In extreme environ ...

of icy worlds. The main science objectives for Ganymede, and to a lesser extent for Callisto, are: * Characterisation of the ocean layers and detection of putative subsurface water reservoirs * Topographical, geological and compositional mapping of the surface * Study of the physical properties of the icy crusts * Characterisation of the internal mass distribution, dynamics and evolution of the interiors * Investigation of Ganymede's tenuous atmosphere * Study of Ganymede's intrinsic

magnetic field A magnetic field (sometimes called B-field) is a physical field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular ...

and its interactions with the Jovian magnetosphere. For Europa, the focus is on the chemistry essential to life, including organic molecules, and on understanding the formation of surface features and the composition of the non-water-ice material. Furthermore, Juice will provide the first subsurface sounding of the moon, including the first determination of the minimal thickness of the icy crust over the most recently volcanically-active regions. More distant spatially resolved observations will also be carried out for several minor irregular satellites and the volcanically active moon Io.

Science instruments

On 21 February 2013, after a competition, 11 science instruments were selected by ESA, which were developed by science and engineering teams from all over Europe, with participation from the US. Japan also contributed several components for SWI, RPWI, GALA, PEP, JANUS and J-MAG instruments, and will facilitate testing. ; Jovis, Amorum ac Natorum Undique Scrutator (JANUS) :The name is

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

for "comprehensive observation of Jupiter, his love affairs and descendants." It is a camera system to image Ganymede and interesting parts of the surface of Callisto at better than 400 m/pixel (resolution limited by mission data volume). Selected targets will be investigated in high-resolution with a spatial resolution from 25 m/pixel down to 2.4 m/pixel with a 1.3° field of view. The camera system has 13 panchromatic, broad and narrow-band filters in the 0.36 μm to 1.1 μm range, and provides stereo imaging capabilities. ''JANUS'' will also allow relating spectral, laser and radar measurements to geomorphology and thus will provide the overall geological context. ; Moons and Jupiter Imaging Spectrometer (MAJIS) :A visible and infrared imaging spectrograph operating from 0.5 μm to 5.56 μm, with

spectral resolution The spectral resolution of a spectrograph, or, more generally, of a frequency spectrum, is a measure of its ability to resolve features in the electromagnetic spectrum. It is usually denoted by \Delta\lambda, and is closely related to the resolvi ...

of 3–7 nm, that will observe tropospheric cloud features and minor gas species on Jupiter and will investigate the composition of ices and minerals on the surfaces of the icy moons. The spatial resolution will be down to on Ganymede and about on Jupiter. ; UV Imaging Spectrograph (UVS) :An imaging spectrograph operating in the wavelength range 55–210 nm with spectral resolution of <0.6 nm that will characterise

exosphere The exosphere is a thin, atmosphere-like volume surrounding a planet or natural satellite where molecules are gravitationally bound to that body, but where the density is so low that the molecules are essentially collision-less. In the case of ...

s and

aurora An aurora ( aurorae or auroras), also commonly known as the northern lights (aurora borealis) or southern lights (aurora australis), is a natural light display in Earth's sky, predominantly observed in high-latitude regions (around the Arc ...

e of the icy moons, including plume searches on Europa, and study the Jovian upper atmosphere and aurorae. Resolution up to observing Ganymede and up to observing Jupiter. ; Sub-millimeter Wave Instrument (SWI) :A

spectrometer A spectrometer () is a scientific instrument used to separate and measure Spectrum, spectral components of a physical phenomenon. Spectrometer is a broad term often used to describe instruments that measure a continuous variable of a phenomeno ...

using a antenna and working in 1080–1275

GHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or Cycle per second, cycle) per second. The hertz is an SI derived unit whose formal expression in ter ...

and 530–601 GHz with spectral resolving power of ~10⁷ that will study Jupiter's stratosphere and troposphere, and the exospheres and surfaces of the icy moons. ; Ganymede Laser Altimeter (GALA) :A laser altimeter with a spot size and vertical resolution at intended for studying topography of icy moons and tidal deformations of Ganymede. ; Radar for Icy Moons Exploration (RIME) : :An ice-penetrating radar working at frequency of 9 MHz (1 and 3 MHz bandwidth) emitted by a antenna; will be used to study the subsurface structure of Jovian moons down to depth with vertical resolution up to in ice. :During post-launch commissioning of the spacecraft, the RIME antenna failed to properly deploy from its mounting bracket. After several weeks of attempts to free the instrument, it was successfully deployed on 12 May of the same year. ; Juice-Magnetometer (J-MAG) : MAGSCA flight model

:Juice will study the subsurface oceans of the icy moons and the interaction of Jovian magnetic field with the magnetic field of Ganymede using a sensitive

magnetometer A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, ...

. ; Particle Environment Package (PEP) :A suite of six sensors to study the

magnetosphere of Jupiter The magnetosphere of Jupiter is the cavity created in the solar wind by Jupiter's magnetic field. Extending up to seven million kilometers in the Sun's direction and almost to the orbit of Saturn in the opposite direction, Jupiter's magnetospher ...

and its interactions with the Jovian moons. ''PEP'' will measure positive and negative ions, electrons, exospheric neutral gas, thermal plasma and energetic neutral atoms present in all domains of the Jupiter system from 1 meV to 1 MeV energy. ; Radio and Plasma Wave Investigation (RPWI) :RPWI will characterise the plasma environment and radio emissions around the spacecraft, it is composed of four experiments: GANDALF, MIME, FRODO and JENRAGE. ''RPWI'' will use four Langmuir probes, each one mounted at the end of its own dedicated boom and sensitive up to 1.6 MHz, to characterize plasma, and receivers in the frequency range 80 kHz to 45 MHz to measure radio emissions. This scientific instrument is somewhat notable for using

Sonic the Hedgehog is a video game series and media franchise created by the Japanese developers Yuji Naka, Naoto Ohshima, and Hirokazu Yasuhara for Sega. The franchise follows Sonic the Hedgehog (character), Sonic, an anthropomorphic blue hedgehog who battle ...

as part of its logo. ; Gravity and Geophysics of Jupiter and Galilean Moons (3GM) :3GM is a radio science package comprising a Ka transponder and an ultrastable

oscillator Oscillation is the repetitive or periodic variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples of oscillation include a swinging pendulum ...

. 3GM will be used to study the gravity field – up to degree 10 – at Ganymede and the extent of internal oceans on the icy moons, and to investigate the structure of the neutral atmospheres and ionospheres of Jupiter (0.1 – 800 m bar) and its moons. 3GM carries Israeli-built

atomic clock An atomic clock is a clock that measures time by monitoring the resonant frequency of atoms. It is based on atoms having different energy levels. Electron states in an atom are associated with different energy levels, and in transitions betwee ...

"that will measure tiny vacillations in a radio beam". ; Planetary Radio Interferometer and Doppler Experiment (PRIDE) :The experiment will generate specific signals transmitted by Juice's antenna and received by

very-long-baseline interferometry Very-long-baseline interferometry (VLBI) is a type of astronomical interferometry used in radio astronomy. In VLBI a signal from an astronomical radio source, such as a quasar, is collected at multiple radio telescopes on Earth or in space. T ...

to perform precision measurements of the gravity fields of Jupiter and its icy moons.

References

External links

ESA's Juice page

* ttp://www.lpi.usra.edu/opag/Oct2011/presentations/Dougherty.pdf ''Jupiter Icy Moons Explorer'' (2011)br>OPAG October 2011 Presentations

Juice (JUpiter ICy moons Explorer)OPAG March 2012 Presentations

Juice-JAPAN
–

JAXA The is the Japanese national air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satellites into o ...

Juice
–

Juice article on eoPortal by ESA
* YouTube channe
the making of Juice
– ESA
The making of Juice: the film
by ESA {{Navboxes , title= Articles related to Jupiter Icy Moons Explorer , list = {{Jupiter {{Ganymede {{Callisto {{Europa {{European Space Agency {{Venus spacecraft {{Planetary Missions Program Office, Solar System Exploration=y {{2023 in space {{Orbital launches in 2023 {{Solar System probes 2023 in French Guiana Cosmic Vision European Space Agency space probes Missions to Jupiter Orbiters (space probe) Solar System Exploration program Spacecraft launched by Ariane rockets Space probes launched in 2023 April 2023 in South America