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Intro to the JUICE Mission

JUICE stands for JUpiter ICy moons Explorer. It is the first L-class mission in ESA’s 2015-2025 Cosmic Vision programme, where L stands for large. The JUICE spacecraft was launched in April 2023 and is planned to reach the Jupiter system in 2031. The mission aims to explore the conditions for the emergence of life in three of the 4 largest moons of Jupiter: Ganymede, Europa and Callisto.

Once the spacecraft has arrived at Jupiter, it will characterise the three moons of Jupiter that are believed to hold liquid oceans underneath their icy surfaces. These oceans are prevented from freezing due to internal heat generated within the moons as they are stretched by Jupiter’s gravity. Why are these ocean-bearing moons interesting? Water in liquid form is rare in the solar system, but has played a crucial role in the development of life on Earth. Could the oceans under the surfaces of Ganymede, Europa and Callisto also harbour lifeforms?

JUICE will complete a series of firsts in the Solar System. For instance, it will be the first spacecraft to orbit a moon other than our own – Jupiter’s largest moon, Ganymede. On the way to Jupiter, it will also perform the first lunar-Earth gravity assist to save propellant. Some of the main mission milestones are shown below.

JUICE Mission Milestones. Credits: ESA – JUICE Launch kit

In this mission, 5 mysteries of Jupiter will be investigated:

  • Why is Ganymede so unique?
  • What are ocean worlds like?
  • How has Jupiter’s complex environment shaped its moons, and vice versa?
  • What is a typical gas giant planet like – how did it form, and how does it work?
  • Could there be life in the Jupiter system?

To answer these and other questions, JUICE carries 10 scientific instrument packages, listed in the table below. The spacecraft includes components manufactured by the Portuguese companies LusoSpace, Active Space Technologies, Deimos Engenharia and Frezite High Performance (FHP). The RADiation–hard Electron Monitor (RADEM), which is an extension of the PEP instrument sensitive to high energy (up to 5 MeV) electrons and protons, was designed in part by the Laboratory of Instrumentation and Experimental Particle Physics (LIP). Besides contributing to the science, RADEM will also trigger alarm signals when the environment radiation dose exceeds safe levels for certain instruments. The RADEM radiation monitor was developed by LIP and EFACEC, in cooperation with the Norwegian company Ideas and the Swiss research institute Paul Scherrer.

In addition to the scientific instrumentation, JUICE carries shields that protect sensitive electronic components from high radiation, gigantic solar panels for power supply, an insulating layer against extreme temperatures, an antenna to send data to Earth, and a computer to solve some problems independently. The antenna has a coating produced by the Porto company FHP and its operating mechanism was developed by Active Space Technologies, based in Coimbra.

Final form for Jupiter. Credits: ESA
Name Function
UVS UV imaging Spectrograph
JANUS An optical camera system
MAJIS Moons and Jupiter Imaging Spectrometer
SWI Sub-millimeter Wave Instrument
GALA GAnymede Laser Altimeter
RIME Radar for Icy Moon Exploration
3GM Gravity & Geophysics of Jupiter and Galilean Moons
PEP Particle Environment Package
J-MAG A magnetometer instrument for Juice
RPWI Radio & Plasma Wave Investigation

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