Case study

Jupiter icy moon explorer (JUICE)

UK involvement in the mission to make detailed observations of the giant gaseous planet Jupiter and three of its largest moons: Ganymede, Callisto and Europa.

Artist's impression: JUICE around Ganymede with Jupiter in background.

Artist's impression: JUICE around Ganymede with Jupiter in background. Credit: ESA (acknowledgement: ATG Medialab)

Understanding our Solar System

JUICE is an ESA Large class science mission and will consider two key themes of ESA’s Cosmic Vision 2015 – 2025: What are the conditions for planet formation and the emergence of life? and how does the Solar System work?

As well as studying the gas giant in detail, JUICE will make detailed observations of the giant gas planet and its large ocean-bearing moons – Callisto, Europa and in particular the largest, Ganymede. Ganymede is bigger than Mercury, and unusually for a moon, it has its own magnetic field. The mission will examine how this interacts with Jupiter’s magnetic field. It will also look for evidence of a habitable environment in the vast ocean believed to exist under Ganymede’s icy crust.

JUICE will complete a number of firsts. It will spend time orbiting Ganymede and will be the first spacecraft ever to orbit a moon other than our own. On the way to Jupiter, it will perform the first ever lunar-Earth gravity assist, to conserve propellant.

JUICE launched in April 2023 and was the last ESA mission to launch on an Ariane 5 launch vehicle from ESA’s spaceport in Kourou, French Guiana. The spacecraft will spend around 8 years cruising to Jupiter, during which it will complete fly-bys of Venus, Earth and the Earth-Moon system.

It will reach Jupiter in July 2031 but will start making science observations from six months out. Over its 4-year operational phase, JUICE will spend many months orbiting Jupiter, completing fly-bys of Europa, Ganymede and Callisto, and finally will settle into orbit around Ganymede.

Ten scientific instruments on one unique space craft

The JUICE spacecraft is an international collaboration between ESA and several member states. It carries 10 scientific instruments which comprise the most powerful remote sensing, geophysical and in-situ payload complement ever flown to the outer Solar System.

Many funding agencies, organisations and companies have contributed to the development of JUICE.

JUICE’s Instruments
JANUS An optical camera system
MAJIS Moons and Jupiter Imaging Spectrometer
GALA GAnymede Laser Altimeter
J-MAG A magnetometer instrument for Juice
RPWI Radio & Plasma Wave Investigation
UVS UV imaging Spectrograph
SWI Sub-millimeter Wave Instrument
RIME Radar for Icy Moons Exploration
PEP Particle Environment Package
3GM Gravity & Geophysics of Jupiter and Galilean Moons

A remote sensing package (JANUS, MAJIS, UVS, SWI) includes imaging and spectral imaging capabilities.

A geophysical package comprises a laser altimeter (GALA) and a radar sounder (RIME) for exploring the moons’ surface and subsurface, and a radio science experiment (3GM) to probe the atmospheres of Jupiter and its satellites and to measure their gravity fields.

An in-situ package contains a powerful suite of instruments to study the particle environment (PEP), a magnetometer (J-MAG), and a radio and plasma wave instrument (RPWI).

How is the UK involved?

The UK Space Agency has invested approximately £9 million in JUICE. This covers all UK involvement in the mission up to the end of launch plus commissioning. The UK leads on one of the science instruments and is contributing hardware to two others.

The UK has led the development of the magnetometer, J-MAG. The team at Imperial College London is led by Principal Investigator Professor Michele Dougherty.

Scientific measurements from the J-MAG magnetometer will lead to an understanding of the formation of the icy moons, helping to characterise their oceans and assess their potential for habitability, and will provide deep insight into the behaviour of rapidly rotating magnetised bodies.

The University of Leicester, led by Dr Nigel Bannister, has contributed to the radiation-hardness and mechanical design of J-MAG.

The UK Space Agency has also funded the Open University under the Management of Dr Mark Leese to characterise, test and calibrate the CMOS imaging sensors for the Italian-led optical camera system, JANUS.

These sensors have been specially designed by Teledyne-e2v in Chelmsford to withstand the harsh radiation environment of Jupiter.

University College London’s Mullard Space Science Laboratory has provided the Solid-State Detectors for the (Swedish-led) Particle Environment Package (PEP), and Aberystwyth University has contributed to the radiation design of PEP instrument suite.

Published 28 April 2014
Last updated 20 October 2023 + show all updates
  1. Sight changes made to text throughout the page to make it past tense, reflecting that JUICE has now launched.

  2. Updated with launch date and other information.

  3. Updated November 2021.

  4. Updated May 2021.

  5. Mission content updated.

  6. First published.