JUICE (Jupiter Icy Moon Explorer) was successfully launched from French Guiana today, April 14, 2023, at 2.15 pm Italian time, and its investigation will focus on Jupiter and its icy moons - Ganymede, Europa and Callisto.

It will reach the planet in 2031, carrying out its three-year study mission in the Jupiter environment, much like a miniature solar system. There, it will have to complete a complex series of tasks: from observing Jupiter's atmosphere and magnetosphere to studying the interaction of the Galilean moons with the planet.

The probe will visit Callisto (the most crater-covered celestial body in the solar system), which may be hiding an inner ocean, and will examine the uppermost layers of Europa's ice cap, identifying appropriate sites for possible in-situ exploration. JUICE will end its mission in September 2035 by orbiting Ganymede, the only moon with its own magnetic field, for four months. It will be the first time a space probe will orbit a satellite other than our Moon. In its final phase, the mission will unveil its most eagerly awaited results, observing details of Ganymede's icy surface and providing an insight into its internal structure.

The comparative study of the three Jovian satellites in a single mission will make it possible to understand the causes of their diversity, dominated by Jupiter's influence, and provide new data on the formation of planetary systems.

One of JUICE's main scientific themes concerns the possible habitability of the giant planets' environments, particularly the possibility that Jupiter's icy satellites could represent an environment capable of supporting biotic activity over long periods.

The choice of the JUICE mission is the culmination of a process that began in 2004 when the European Space Agency (ESA) launched a broad consultation of the scientific community to identify the goals of European planetary exploration over the next decade.

The ESA mission, selected by the Space Programme Committee, sees an important participation of Italy through the Italian Space Agency (Agenzia spaziale italiana  - ASI) and various bodies and universities, including Sapienza University of Rome, which participated in the construction of three instruments: the 3GM radio science and geophysics instrument, the RIME radar, and the JANUS camera.

3GM (Gravity and Geophysics of Jupiter and the Galilean Moons), led by Luciano Iess, from the Department of Mechanical and Aerospace Engineering of Sapienza University of Rome, comprises a Ka-band transponder and an ultra-stable oscillator (USO), built by the Israeli Space Agency (ISA). This set of instruments will be used to measure the gravity field and deep structure of icy moons, to determine the extent of Ganymede's inner ocean, and to study Jupiter's atmosphere. 3GM's instrumentation also includes a high-precision accelerometer (HAA), which is needed to calibrate the satellite's internal dynamic disturbances, mainly due to propellant movement in the tanks.

RIME (Radar for Icy Moon Exploration) is a subsurface radar optimised to penetrate the ice surface of Galilean satellites down to a depth of 9 km with a vertical resolution of up to 30 m. The RIME radar is the result of a collaboration between the University of Trento and NASA's Jet Propulsion Laboratory (JPL).

JANUS (Jovis, Amorum ac Natorum Undique Scrutator) is an optical chamber for studying morphology and global regional and local processes on moons and mapping Jupiter's clouds.

Also significant is the Italian involvement in the optical head of the MAJIS (Moons and Jupiter Imaging Spectrometer) instrument, a hyper-spectral imaging spectrometer for observing the characteristics and minor species of Jupiter's troposphere as well as for the characterisation of ices and minerals on the icy moons.

Many Italian and foreign universities and research institutes participate in the scientific teams of the four instruments funded by ASI. The Principal Investigators of 3GM, RIME and JANUS belong respectively to Sapienza University of Rome, the University of Trento and INAF - Istituto Nazionale di Astrofisica (National Institute for Astrophysics), to which the Co-Principal Investigator of MAJIS also belongs.

Further Information  

Luciano Iess
Department of Mechanical and Aerospace Engineering
luciano.iess@uniroma1.it