It’s the European Space Agency’s major planetary mission: Juice will leave Earth on April 13 to study Jupiter’s icy moons. The journey lasts 8 years. Upon arrival, the probe will make 35 flybys before entering orbit around Ganymede. Objective: to test whether these moons are potentially habitable.
If Juice needs to be summed up in a few numbers, let’s remember these: 2,000 employees, 18 offices, 23 participating countries, 83 partner companies through 116 contracts under the main Airbus Defense & Space contractor, all for a total budget of 1.6 billion euros . Futura visited the clean room several times in Toulouse, where the Juice probe was tested for more than a year before leaving for Kourou. It’s a whole community revolving around this mission and responding to new scientific goals.
Jupiter’s moons have never been examined so closely. Jupiter has been visited by NASA probes before, with flybys by the Pioneer, Voyager, Ulysses, New Horizons, Cassini probes, but also the Galileo and Juno orbiters (still active). Juice belongs to a new generation trying to answer the question of the possible existence of elemental extraterrestrial life in the Jovian system targeting the moons Europa, Ganymede and Callisto.
Oceans under ice and magnetism
The scientific goals of Juice are diverse, but above all of a new nature. They reflect the new questions we draw from the legacy of exploring the Jupiter system to date, in a context where we now know of thousands of exoplanets of the same nature as Jupiter.
Our slideshow on Jupiter
Habitability is arguably the most exciting concept. The community is now certain that there is an ocean beneath the icy surfaces of Europa, Ganymede, and Callisto. The presence of liquid water indicates the existence of extraterrestrial life. Without being able to realize it, Juice will characterize these three moons to find out if this life is possible or not.
Studying the Exo-Jupiters raises questions about their formation as well as their ecosystem. It is therefore a matter of characterizing Jupiter’s magnetism and knowing how it interacts with the planet’s atmosphere and with the moons, particularly Ganymede, which is the only one with its own magnetic field. This is to learn more about the rings of Jupiter, the other moons of the Jovian system including Io, and also about the atmosphere of the giant planet.
A (very) long journey
Launch is scheduled for April 13 at 2:15 p.m. from Guiana Space Center aboard the penultimate Ariane 5 flight. In order to be able to send the 5,100-kilogram probe to Jupiter, a heavy launch vehicle is required. Of these, 2,900 kilos are fuel. It is used sparingly to accommodate most on-site operations. Thus, a direct path to Jupiter is excluded and several gravitational aids are planned:
- August 2024: Moon and Earth flyby;
- August 2025: Venus Flyby;
- September 2026: Earth flyby;
- January 2029: Earth flyby.
Arrival in the Jupiter system is scheduled for July 2031, after 8 years of travel! During the various overflights, the scientific instruments are switched on, tested and calibrated. Once arrived, the Juice probe will have enough fuel to conduct 12 flybys of Ganymede, 21 flybys of Callisto and 2 flybys of Europa. The latter is avoided because its radiating environment is very harsh, then the moon is targeted by NASA’s Europa Clipper mission, which is scheduled to land on it around 2030.
Voyage of the Juice probe and visit to the Jupiter system. © ESA, YOUTUBE
Strong scientific instrumentation
The probe’s satellite platform has been sufficiently optimized to accommodate 285 kilos of scientific instruments. Juice has ten of these, along with a Radiation Monitor (Raem). Instruments include an optical camera (Janus), a visible and near-infrared spectrometer-imager developed by the Space Astrophysics Institute (Majis), instruments to perform submillimeter measurements (SWI), radar (Rime), and radio and plasma waves (RPWI) , an ultraviolet spectrograph (UVS provided by NASA), a laser altimeter (Gala), a magnetometer (J-MAG), a radio science experiment (3GM) and a particle sensor (PEP).
The instruments are under French, German, British, Italian, Dutch, Swedish and American project management for UVS. American laboratories were also involved in other instruments, as was the Japanese space agency. These instruments are designed to operate in the harsh environment of Jupiter. Juice features radiation protection, MLI layers (Multi-Layer Insulation Blanket) to withstand extreme temperatures (from -230°C around Jupiter to +250°C when flying over Venus). Finally, to power all systems, ESA chose to equip the spacecraft with solar panels instead of using an RTG. Given the distance from the sun, the area of the panels reaches 85 m².