“Weather red”, risk of lightning! Just minutes before the final count, the launch of the European probe JUICE to Jupiter was postponed until Friday by Arianespace. The flagship mission of the European Space Agency should therefore be sent to the Jovian system with a day’s delay, at the same time.
JUICE is an acronym for JUpiter ICy moons Explorer: this flagship mission of the European Space Agency (ESA) aims to observe in detail the giant gaseous planet and three of its more 80 monday – according to some counts, it could even possess 95.
Europe, Ganymede et Callisto are particularly interesting worlds because, under their pack ice, oceans of liquid water move, lands conducive to the emergence of life. Take-off scheduled from French Guiana at 2:15 p.m. Swiss time this Thursday, April 13.
>> To attend the launch of JUICE live from 1:45 p.m. on Friday, the ESA Web TV channel:
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>> The same program with interpreters in French: ESA web TV Two
These environments are so far from the Sun that astronomers have long excluded them from the zone of the Sun. Solar system considered habitable, “which until recently stopped at Mars”, explains to AFP the astrophysicist Athéna Coustenis, one of the scientific managers of the European probe.
Discoveries by the Galileo (1995) and Juno (2016) probes around Jupiter have pushed the frontiers of research. JUICE will go even further thanks to its ten dedicated instruments, some of which are designed in Switzerland (read box).
>> Watch Monday’s 7:30 p.m. report:
Ganymede, the star
Ganymede photographed by NASA’s Juno probe during its flyby of the Jovian moon, June 7, 2021. [JunoCam – NASA/JPL-Caltech/SwRI/MSSS]
Ganymede is the main target of the mission. It is the largest moon in our Solar System and the only one to generate its own magnetic field, which protects it from dangerous radiation from the Universe: a real asset.
Its gigantic ocean is trapped between two thick layers of ice and would be several tens of kilometers deep. JUICE’s instruments will inspect this expanse of salt water from every angle to assess its depth, distance from the surface and, it is hoped, composition. The spacecraft will orbit about eight months around Ganymede, which it will be able to approach up to 200 kilometers in altitude, sheltered from radiation. It will place itself in orbit around Ganymede in 2034 and see if its environment – which seems stabilized – has seen living things appear and stay there.
At the bottom of the earth’s abyss, it is possible to detect forms of life: certain ecosystems are able to survive without light and are teeming with micro-organisms such as bacteria or archaea, unicellular cells without a nucleus… a similar life was or is possible on this other world?
Unlike missions to Mars, in search of traces of ancient life that has now disappeared, the exploration of icy moons seeks environments that are still habitable; what the red planet is no longer.
Habitability also requires a power source. Under the freezing temperatures of the Jovian system, it does not come from the Sun but from the gravity that Jupiter exerts on its satellites: “tidal effects” similar to what happens on Earth with the Moon. This phenomenon makes it possible to “dissipate the heat inside the moons and to maintain the water in a liquid state”, deciphers Francis Rocard, planetary scientist at the National Center for Space Studies (CNES).
>> Read also:
On Pluto, the volcanoes are made of ice
Two more promising moons
Europa and its surface of domes and ridges; disturbed terrain including crustal plates that have broken up and repositioned. The reddish areas are associated with internal geological activity and the blue with relatively old icy plains. [JPL/University of Arizona – NASA]
Scientists believe that Europa has an iron core, a rocky mantle, and a saltwater ocean; this young and active celestial object does not have a magnetosphere.
Its surface is a fractured frozen crust that moves a lot, creating a kind of “ice tectonics”, with plates interlocking with each other: when Europa moves away from Jupiter, the fractures open and deposits from the ocean below rise to the surface. It appears to shoot water into space via steam jets and geysers.
Note that NASA will launch Europa Clipper in October 2024: this probe will arrive just before JUICE due to the trajectories chosen and will work in concert with the European mission. Their data will be complementary.
>> Read also:
Does life exist on the ocean worlds of our Solar System?
As for Callisto, it is the oldest object in the Solar System and the one with the most craters; it could also have an ocean of salt water below its surface. JUICE will fly over this moon twenty-one times to get a sense of the environment that existed when Jupiter was still very young.
>> An English page from NASA: Jupiter Resources
A model of the solar system
Jupiter, the oldest and the most massive planet of the Solar System, is also very important for the understanding of this arrangement in which evolve our eight planets and all their moons.
As Jupiter is also the largest planet and has a composition similar to the Sun – mostly hydrogen and helium – understanding its formation is considered important for understanding the origin of the Earth.
In addition, Jupiter exerts an influence on its moons, but also on rings and asteroids. Life has not been able to develop there because the temperatures there, the pressure and the materials that characterize it are probably too extreme and volatile for organisms to adapt to.
>> Read also:
Sixty years of searching for extraterrestrial life… and still nothing
Stéphanie Jaquet and the agencies