JUpiter ICy moons Explore (JUICE) is the first large-class mission in ESA’s Cosmic Vision programme, in which Leonardo is participating as part of the Italian Space Agency’s (ASI) significant contribution. JUICE’s objective is to spend more than three years making detailed observations of the giant gaseous planet Jupiter and three of its largest moons – Ganymede, Callisto and Europa.
The spacecraft’s 600 million km journey to Jupiter is scheduled to start in June 2022 on-board an Ariane 6 rocket. Following launch, there is a planned first flyby of Earth in May 2023, Venus in October 2023, a second flyby of Earth in September 2024, Mars in February 2025 and a final flyby of Earth in November 2026, all of which will put the JUICE spacecraft on its trajectory to Jupiter, where it is expected to arrive in October 2029.
During its 3.5 years in the Jovian system observing Jupiter, Ganymede, Callisto and Europa, JUICE will address two themes of ESA’s Cosmic Vision programme: What are the conditions for planet formation and emergence of life? And how does the Solar System work? We already know that under their icy surfaces, the moons contain the largest water oceans in the solar system.
Powering JUICE through solar energy
With the production of the JUICE photovoltaic (solar electricity) panels, Leonardo is pushing new boundaries and demonstrating its technological excellence, having previously produced similar panels for the Rosetta mission.
JUICE’s panels cover a total area of 85 square meters, becoming the largest ever built for an interplanetary mission. Leonardo’s array uses Gallium Arsenide (GaAs) solar cells – crystals that convert sunlight into electric current. Since the radiation environment is dominated by electrons, solar arrays can be used to provide electrical power, with GaAs solar cells optimised for low intensity lighting and low temperatures. This is a critical feature, because at such a great distance from the Sun, the solar panels will reach temperatures of -230°c. Furthermore, there is 27 times less light at Jupiter than on Earth, so a large surface is needed to capture enough light and produce sufficient electricity.
Putting this into context, while the whole solar array (85m2) produces more than 30kW on Earth – which could easily power a small residential street – once on Jupiter, and despite its high efficiency, it will produce enough energy to barely power a simple hair dryer.
Contributing to JUICE’s scientific payload
To achieve its mission objectives, JUICE will carry the most powerful scientific payload ever flown to the outer Solar System. It will feature ten state-of-the-art instruments including cameras, spectrometers, an ice-penetrating radar, an altimeter, radio-science experiment and sensors to monitor the Jovian system’s magnetic fields and charged particles.
Leonardo is contributing to the production of the JANUS optical telescope and the MAJIS visible and infrared spectrometer, which are highly technological scientific instruments of great importance to the mission.
JANUS is being developed by Leonardo under the responsibility of ASI, working in partnership with Italy’s National Institute for Astrophysics (INAF), which is providing scientific guidance. The optical camera will study global, regional and local morphology and processes on the moons, and perform mapping of Jupiter’s clouds. JANUS will have 13 filters, a 1.3 degree field of view, and spatial resolution up to 2.4m on Ganymede and about 10km at Jupiter.
MAJIS is being developed by the French institute IAS, with an important contribution from Leonardo, funded by the French National Space Agency (CNES) and ASI. The multi-spectral spectrometer will observe tropospheric cloud features and minor species on Jupiter, as well as identify ices and minerals on the surfaces of the icy moons. MAJIS will cover the visible and infrared wavelengths from 0.4 to 5.7 microns, with spectral resolution of 3-7 nm. The spatial resolution will be up to 25m on Ganymede and about 100km on Jupiter.
JUICE mission spacecraft: ESA/ATG medialab; Jupiter: NASA/ESA/J. Nichols (University of Leicester); Ganymede: NASA/JPL; Io: NASA/JPL/University of Arizona; Callisto and Europa: NASA/JPL/DLR