An 8-year journey
The European Space Agency (ESA) will send an orbiter to explore the strange moons of Jupiter. The Jupiter Icy Moons Explorer (JUICE) will take off on April 13 from Kourou, French Guiana, and begin its eight-year journey to Jupiter.
Designed to study Europa, Ganymede and Callisto
The orbiter is designed to study Europa, Ganymede and Callisto, three of Jupiter’s largest moons. It will make two close flybys of Europa and 12 flybys of Callisto during the first phase of its mission, from 2031 to 2034, and then orbit Ganymede for the remainder of its mission.
It has a liquid ocean under its ice cap.
Although Ganymede may seem an unconventional choice-Jupiter’s smallest moon, Europa, is commonly regarded as more likely to have conditions suitable for life-it is the largest moon in the solar system, making it relatively easy to reach and orbit. Like Europa and Callisto, it is believed to have a liquid ocean beneath its ice shell.
Many mysteries to solve
«Ganymede in principle is less interesting than Europa, but because it is a larger moon, also potentially with water inside, and with a magnetic field, Ganymede has many mysteries to solve,» says Olivier Witasse, the mission’s project scientist at ESA. «One of the big questions is whether we could have around Jupiter a place where there are habitable conditions, and Ganymede is one of those places.»
The largest in the solar system
The possible habitable environment is in Ganymede’s liquid ocean, which is believed to be the largest in the solar system. But we know very little about it, so it’s unclear whether it could have the right conditions for life. JUICE will measure the location, composition and depth of the water in hopes of finding enough promise to justify a future mission under the ice to look for real signs of life. «If you want to look inside the ocean, you need to know where the ocean is,» Witasse says.
JUICE will also observe the other moons from afar.
JUICE’s measurements of the ocean will be aided by Ganymede’s internally generated magnetic field, the only one on any moon. The study of the magnetic field will also help unravel the internal structure of Ganymede. In addition, the mission will map the three moons and study the composition of their icy crust for signs of geological activity. It will use radar to penetrate the crust and measure for the first time the depth of the moons’ seas and their depth underground. Since the mission’s goal is, in part, to understand the Jupiter system as a whole and the possibility of life on similar exoplanets, JUICE will also observe the other moons from afar and make detailed observations of Jupiter itself.
