The European probe Juice launched successfully from Kourou on Friday, marking the start of its eight-year odyssey to Jupiter and its icy moons, in search of environments favorable to the appearance of extra-terrestrial life.
Shortly after taking off aboard an Ariane 5 rocket, at 12:14 GMT, the space probe separated from the launcher, 1,500 km above the Earth as planned.
The Ariane 5 mission "is a success," said Stéphane Israël, President of Arianespace, from the Guiana Space Center.
The announcement sparked applause in the Jupiter control room where several personalities were gathered, including Belgian King Philippe and French astronaut Thomas Pesquet.
The emotion and the relief were palpable there, while Thursday the launch had to be postponed for 24 hours, due to the risk of thunderstorms.
"I was very stressed, it was a roller coaster!" Reacted to AFP the director general of the European Space Agency (ESA) Josef Aschbacher. "I am extremely proud for Europe because Juice is the biggest mission of the decade, and the most complex ever sent to Jupiter", he rejoiced.
Once the separation was successful, the teams still had to wait for the satellite to send out its first signal, which it eventually did after a few - long - minutes of suspense.
The six-tonne probe was then able to deploy its huge solar panels, the size of a basketball court, another crucial step. "That's it, we're starting!", Olivier Witasse, scientific manager of Juice for ESA, told AFP.
"We will have to wait another 17 days for the probe to deploy its antennas, and in three months we will have the final diagnosis on its performance. We will then be launched into the interplanetary travel phase", explains Nicolas Altobelli, in charge of the mission.
The cruise of Juice (Jupiter Icy Moons Explorer) promises to be long and "not at all quiet", underlines Carole Larigauderie, head of the Juice project at the National Center for Space Studies (CNES).
Juice will reach its final destination in 2031, over 600 million miles on average from Earth. Unable to reach Jupiter directly, the machine will have to go through complex gravitational assistance maneuvers which consist in using the force of attraction of other planets to gain speed.
By a flyby Moon-Earth first, then of Venus (2025), then again of the Earth (2029), before taking its momentum towards the mastodon of the solar system and its largest moons, discovered by Galileo ago 400 years: Volcanic Io and her three frozen companions Europa, Ganymede and Callisto.
This is the first time that space Europe has gone to explore a planet in the outer solar system, which starts after Mars.
"In small steps, space exploration is pushing back the frontiers of knowledge," Thomas Pesquet told AFP.
Designed by Airbus, Juice carries ten scientific instruments (optical camera, imaging spectrometer, radar, altimeter, magnetometer, etc.). Which will allow to better understand the Jovian system, considered as a "mini-solar system".
But the main quest is to find environments conducive to the appearance of life. If Jupiter, a gaseous planet, is uninhabitable, its moons Europa and Ganymede are ideal candidates called "ocean-worlds": under their surface of ice, they shelter oceans of liquid water, but only water in a liquid state makes life possible.
Juice targets Ganymede: in 2034, it should be placed in orbit around this natural satellite, the largest in the solar system and the only one to have a magnetic field protecting it from radiation.
Trapped between two thick crusts of ice, Ganymede's ocean is extremely deep. There would be "five or six times more liquid water on Ganymede than on Earth", decrypts Olivier Witasse.
Previous observations in orbit have suggested that this water would be salty, "but life on Earth started in saltwater oceans", adds the scientist.
The challenge for Juice is to know the composition of this ocean, in particular to know if an ecosystem could develop there.
"We know that on Earth, there is a subglacial lake (in Antarctica, editor's note) where we found a kind of mucus which develops - therefore life", notes Carole Larigauderie.
"If Juice manages to prove that Ganymede is habitable so that he can go and check that there is life in the future, that would be fabulous!", She exclaims.
The launch of Juice, at a cost of 1.6 billion euros, comes in the midst of a launcher crisis for Europe, which is almost deprived of autonomous access to space after the departure of Russian Soyuz rockets from Kourou, the Ariane 6 cumulative delays and the failure of the first commercial flight of Vega C.
Friday's flight is the penultimate Ariane 5 before the first Ariane 6 scheduled for late 2023.
04/14/2023 17:50:25 - Kourou (AFP) - © 2023 AFP
