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JUpiter ICy moons Explorer

COSPAR ID: 2023-053A


The JUpiter ICy moons Explorer (JUICE) is a European Space Agency (ESA) mission to make multiple flybys of Jupiter's satellites Ganymede, Callisto, and Europa and then to go into orbit around Ganymede. The science goals focus on Jupiter and its system, with particular emphasis on Ganymede as a planetary body and potential habitat. The primary science objectives for Ganymede (most of these apply to Callisto as well) are: characterization 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 theinteriors; investigation of the exosphere; and study of Ganymede's intrinsic magnetic field 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.

Mission Profile

JUICE launched on 14 April 2023 at 12:14 UTC (8:14 a.m. EDT) on an Ariane 5 from the European Spaceport in Kourou, French Guiana. Spacecraft separation took place at 12:42 UTC. After an 8 year cruise to Jupiter, utilizing Earth, Moon, and Venus gravity assists, JUICE will go into orbit around Jupiter in July 2031. The spacecraft will use flybys of Ganymede and Callisto to optimize the orbit. This will include flybys of Europa. These orbits will be used to study Jupiter and its moons, and then it will be inserted into a highly elliptical orbit around Ganymede. The orbit will evolve to a 5000 km circular orbit, and will be lowered into a 500 km circular orbit. After mapping and other investigations at this altitude, it will lowered again to a 200 km circular orbit. The nominal mission ends after about 3 years, there is the possibility of an extension to the mission of 200 or more days. In either case the mission will end with an impact on the surface of Ganymede.

Spacecraft and Subsystems

The dry mass of 2420 kg includes the launch adapter. 3650 kg of chemical propellant will be required for orbit insertions and maneuvers. The spacecraft will be powered by a large bank (85 square meters) of ten solar arrays employing 23,560 GaAs solar cells optimized for low-intensity / low-temperature conditions. The arrays are arranged in two wings in a cross-like pattern, stretching 27 meters from tip-to-tip, and can produce about 850 W power at Jupiter. Power is stored in a 5-battery bank. Including the solar arrays, JUICE is 16.8 x 27.1 x 13.7 meters in size.

Communications will be primarily via a fixed 2.5 meter diameter high-gain antenna as well as 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. A number of booms and antennas protrude from the spacecraft for the science instruments (see below).

The JUICE main engine is a hypergolic bi-propellant (mono-methyl hydrazine and mixed oxides of nitrogen) 425 N thruster. 100 kg of multilayer insulation provide thermal control. The spacecraft is 3-axis stablized using momentum wheels. Radiation shielding will be used to protect onboard electronics from the Jovian environment.

The JUICE science payload has a mass of 280 kg 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 submillimeter 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 10.6-meter deployable boom will hold J-MAG and RPWI , a 16-meter long deployable antenna will be used for RIME. Four 3-meter booms carry parts of the RPWI instrument. The other instruments are mounted on the spacecraft body, or for 3GM, within the spacecraft bus.

Image credit: ESA

Alternate Names

  • JUpiterICymoonsExplorer
  • 56176

Facts in Brief

Launch Date: 2023-04-14
Launch Vehicle: Ariane 5
Launch Site: Kourou, French Guiana
Mass: 2420 kg
Nominal Power: 850 W

Funding Agency

  • European Space Agency (International)


  • Planetary Science

Additional Information

Questions and comments about this spacecraft can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Dr. Olivier WitasseProject ScientistESA-European Space Research and Technology
Dr. Giuseppe SarriProject ManagerEuropean Space
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