Science Objectives


The focus of JUICE is to characterise the conditions that may have led to the emergence of habitable environments among the Jovian icy satellites, with special emphasis on the three ocean-bearing worlds, Ganymede, Europa, and Callisto. Ganymede is identified for detailed investigation since it provides a natural laboratory for analysis of the nature, evolution and potential habitability of icy worlds in general, but also because of the role it plays within the system of Galilean satellites, and its unique magnetic and plasma interactions with the surrounding Jovian environment. JUICE will determine the characteristics of liquid-water oceans below the icy surfaces of the moons. This will lead to an understanding of the possible sources and cycling of chemical and thermal energy, allow an investigation of the evolution and chemical composition of the surfaces and of the subsurface oceans, and enable an evaluation of the processes that have affected the satellites and their environments through time. The study of the diversity of the satellite system will be enhanced with additional information gathered remotely on Io and the smaller moons. The mission will also characterise the diversity of processes in the Jupiter system that may be required in order to provide a stable environment at the icy moons on geologic time scales, including gravitational coupling between the Galilean satellites and their long term tidal influence on the system as a whole. JUICE will carry out extensive new studies of Jupiter’s atmosphere, magnetosphere and their interaction with the satellites to further enhance our understanding of the evolution and dynamics of the Jovian system.

The Red Book provides a scientific, technical and management summary of the JUICE definition study that was performed from February 2012 to October 2014.

JUICE scientific investigations are also described in Grasset et al., JUpiter ICy moons Explorer (JUICE): An ESA mission to orbit Ganymede and to characterise the Jupiter system, 2013.


May 2012: Mission selection

February 2013: Payload selection

November 2014: Mission adoption

July 2015: Prime industrial contractor selection

Mars 2016: Mission and System Requirements Review completed

March 2017: Spacecraft Preliminary Design Review completed

June 2017: Instrument Preliminary Design Reviews completed

December 2017: Ground Segment Requirements Review completed

December 2018: Ground Segment Design Review completed

March 2019: Spacecraft Critical Design Review completed

April 2019: Science Ground Segment Design Review completed

September 2019: Start of the assembly of the spacecraft flight model

November 2019: Instrument Critical Design Reviews completed

November 2022: Ground Segment Readiness review completed

18 January 2023: Qualification and acceptance review completed

9 February 2023: Spacecraft shipped to Kourou

22 February 2023: Science ground segment Readiness review completed

14 April 2023: Launch from CSG

July 2023: End of the Near Earth Commissioning /  start of the cruise phase