Credit Airbus DS

JUICE 木星氷衛星探査計画 ガニメデ周回衛星


Science JUICEのサイエンス

太陽系創世記と地球外生命体を探る史上最大級のグレートジャーニー4JUICE:JUpiter ICy moons Explorer

JUICE, JUpiter Icy moons Explorer, is an international spacecraft exploration to the Jovian system, led by ESA (European Space Agency) in collaboration with Japan and the United States.

The spacecraft will be launched in 2022 and will arrive at the Jovian system in 2029. By 2032, it will enter orbit around Ganymede. The JUICE mission is our "great journey" to the outer Solar system.


To Solve the Mystery on the Origin of Our Solar System

How did our Solar System form? Where did Earth's atmosphere and water come from? Jupiter may be a key to solve these questions. Jupiter is 300 times heavier than Earth and is the largest gas giant in the Solar System. Owing to Jupiter's strong gravity, the structure of our Solar System has been determined in the early Solar System.

When and how did Jupiter form? Since Jupiter has a dense atmosphere, direct observations of Jupiter’s building materials are difficult. However, its moons are thought to have formed from the same building materials. JUICE will investigate the chemistry of a geologically non-active, Jovian icy moon, Callisto, which is a “fossil” to reveal the origin of the Jovian system.

Search for Extraterritorial Life

Jovian icy satellites look like snowballs in the space, but their interiors can be heated by Jupiter’s strong gravity and radioactive elements within the rocky cores. Some of the geologically-active icy moons would possess liquid subsurface oceans. Does Europa or Ganymede have subsurface oceans? Is the oceanic chemistry similar to that of Earth? The JUICE mission will address these questions concerning the habitability of the icy moons.

The Most Powerful Accelerator in the Solar System

Jupiter is a dynamic planet. Jupiter’s magnetic field rotates at a high velocity. The magnetic field of Jupiter accelerates surrounding plasma from the Sun and causes large-scale aurora. The JUICE mission aims to clarify the dynamics and physical mechanisms of the dynamic phenomena.

About Jupiter 木星とその個性的な衛星たち

JUICE 木星 アイコン Jupiter

The largest planet in the Solar System. Jupiter is 300 times heavier than Earth. Owing to its strong gravity, Jupiter has determined the structure of the Solar System in the early stages. JUICE will explore the atmospheric composition, dynamics, magnetic field, and plasma environments.

JUICE イオ アイコン Io

The innermost Jovian moon, mostly made of rocks. Due to tidal heating caused by the Jupiter’s gravity, Io becomes the most geologically active object in the Solar System. Any flyby is not planned in the JUICE mission, but the spacecraft will observe Io’s geological and plasma activities while orbiting around Jupiter.

JUICE エウロパ アイコン Europa

The geologically-active icy moon that possesses a liquid subsurface ocean, which is covered by the icy crust. Europa may possess habitable hydrothermal systems, similar to those of Earth's ocean, on the seafloor. JUICE will perform flybys to Europa to examine its subsurface ocean and geological activities.

JUICE ガニメデ アイコン Ganymede

The Jupiter’s largest moon. Ganymede is the only moon that has magnetic field in the Solar System. Ganymede may also have an liquid subsurface ocean. This moon may have been geologically active in 2 billion years ago, but the current geological activity is largely unknown. Ganymede is the JUICE's main research target. The spacecraft will examine its subsurface ocean, chemistry, geological activities, and magnetic field from orbit around Ganymede.

JUICE カリスト アイコン Callisto

The outermost Jovian moon. Calisto may be undifferentiated. This means that building materials of the Jovian system would be preserved in Callisto. Through more than 30 flybys to Callisto, JUICE will investigate the chemistry and geology of this icy moon.


credit:Airbus DS

JUICE Spacecraft

JUICE spacecraft needs to endure in Jupiter's harsh radiation environments during the mission time. Its solar panels will create electric power even under weak sunlight at around Jupiter’s orbit.

Mass (with propellant) : Approx. 2900kg
Payload : 219kg
Payload power consumption : 180W
Power Source : 800W solar panels
High-gain Antenna : 3.2m body fixed Ka band
High Δv capability : 2700m/sec
Radiation tolerance : 240krad/10mm
Downlink : 1.4Gbit/day and up

credit:e.g courtesy Airbus DS

Science Instruments

JUICE will carry 11 science instruments. The research teams in Japan are participating into construction of four science instruments (RPWI, GALA, SWI, and PEP/JNA). Japanese researchers will also participate into science teams of two other science instruments (JANUS and J-MAG).

List of Scientific InstrumentsSupplied by JAXA : ★Supplied by NICT : ☆Developed with Japanese Researchers: ◯
Name Lead Researcher (Team)
JANUS High resolution visible spectra camera Junichi HARUYAMA (JAXA)
MAJIS Moons And Jupiter Imaging Spectrometer
☆ ◯ SWI Submillimetre Wave Instrument Yasuko KASAI (NICT)
UVS UV Imaging Spectrograph
RIME Radar for Icy Moons Exploration
3GM Gravity and Geophysics of Jupiter and Galilean Moons
★ ◯ RPWI Radio and Plasma Wave Investigations Yasumasa KASABA (Tohoku Univ.)
★ ◯ PEP Particle Environment Package Kazushi ASAMURA (JAXA)
J-MAG Magnetometer for JUICE Ayako MATSUOKA (Kyoto Univ.)
★ ◯ GALA GAnymede Laser Altimeter Keigo ENYA (JAXA)
PRIDE Planetary Radio Interferometer and Doppler Experiment

JUICE探査機 搭載機器

Schedule JUICE探査スケジュール

The JUICE spacecraft will be launched in 2022 with Ariane 5 rocket. The spacecraft will arrive at the Jovian system in 2029 and will enter Ganymede’s orbit in 2032. The nominal mission will be completed in June 2033.

In 2029–2032, the spacecraft will flyby to Europa twice and to Callisto more than 30 times. The spacecraft will orbit 500 km above the surface of Ganymede.

2012〜 Spacecraft Designing June 2022〜 Ariane 5 Launch January 2029 Fly to the Jovian system Sept. 2032 Entering Ganymede orbit June 2033 Mission Complete

・Developing science instruments
・Mission Planning
・Observation Planning

Could be extended to Sept. 2022

Fly to the Jovian system
Earth – Venus – Earth – Mars – Earth – Jupiter

2029 to Oct. 2030
Callisto Flyby

Investigating Jupiter’s atmosphere and magnetic field
・Investigating Callisto’s geological activity
・Understanding building material of Jupiter and the Solar system in early stage

To January 2013
Europa Flyby
・Investigating Europa’s surface materials and geological activity
・Observing plume eruption from the subsurface ocean
・Evaluating habitability

Could be extended to Dec. 2034

Observations of Jupiter’s atmosphere at high latitudes
・Observing dynamics on Jovian atmosphere and magnetic field
・Observation on interaction between Jupiter and its satellites

・Mapping Ganymede’s surface material
・Investigations on Ganymede’s inner structure and subsurface ocean
・Present Geological Activity
・Formation of Ganymede and the Jovian system

・Investigations of the subsurface ocean
・Investigations of crustal structure
・High-resolution geologic mapping
・Geomorphological investigations
・Survey on local plasma phenomena
・Generation and destruction process of the ionosphere and exosphere
・Investigations of deep interior of Ganymede


JUICE - スケジュール



JUICE-JAPAN aims to investigate the formation and evolution of the Solar System and habitable worlds. The research group is interdisciplinary, including researchers who develop science instruments, planetary scientists who study planetary formation theory, astronomers who perform telescope observations, space physicists who study plasma and magnetic fields, geochemists who examine water-rock interactions. The targets of the research group is not only the JUICE mission but also future missions to the Solar System bodies. JUICE-JAPAN consists of more than 110 researchers at 31 universities and research facilities including JAXA.