Takeoff was scheduled for 12:45 GMT. The postponement was announced just minutes from the final count, from the Jupiter control room where several personalities were invited, including the King of the Belgians Philippe and the French astronauts Thomas Pesquet and German Matthias Maurer.
A few minutes earlier, “a large cloud mass approached and we put a + red weather +, because we absolutely might not proceed with the launch because of this risk of lightning”, explains to AFP Stéphane Israel, the president. from Arianespace.
“To take off, we need three parameters to be green: the preparation of the launcher, the availability of the probe, and the weather which is the last suspense”, he continued. If the relatively predictable altitude winds are announced green for Friday, “we will have to continue to monitor the risk of lightning until the last moment”.
The next attempt is scheduled for the same time on Friday, but 30 seconds before. Unlike conventional launches which have a certain margin to take off, the launch window of the Juice probe is close to one second, due to the particular orbit which is targeted.
Diagram representing the ESA’s Juice (Jupiter icy moons explorer) probe, whose launch on board an Ariane 5 rocket is scheduled for April 13, 2023 in Kourou, French Guiana
©AFP
According to the flight schedule, the six-ton probe is to separate from the rocket 27 minutes following takeoff, at an altitude of around 1,500 kilometers.
This will then be the start of an eight-year odyssey for Juice (Jupiter Icy Moons Explorer), the flagship mission of the European Space Agency (ESA).
The probe must leave to explore Jupiter and its icy moons, in search of habitable environments for extra-terrestrial life forms. It will not reach its destination until 2031, more than 620 million kilometers from Earth, following an eventful journey.
Europe, Ganymede, Callisto
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 Venus (2025), then once more Earth (2029), before taking its momentum towards the mastodon of the solar system and its largest moons, discovered by Galileo ago 400 years: Io the volcanic and its three frozen companions Europa, Ganymede and Callisto.
Juice’s main quest is to find environments suitable for the appearance of life. If Jupiter, a gaseous planet, is uninhabitable, its moons Europa and Ganymede are ideal candidates: under their surface of ice, they shelter oceans of liquid water. Only liquid water makes life possible.
The Juice space probe at the ESA premises in Toulouse on January 20, 2023
©AFP/Archives
Juice targets Ganymede. It will be placed in 2034 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.
The challenge of the mission is to know the composition of its ocean, to find out if an ecosystem might develop there.
“It is the most complex probe ever sent to Jupiter,” said Philippe Baptiste, president of the National Center for Space Studies (CNES). Designed by Airbus, Juice carries ten scientific instruments (optical camera, imaging spectrometer, radar, altimeter, magnetometer, etc.).
It is also equipped with huge 85m2 solar panels (the size of a basketball court) to keep power in an environment where sunlight is 25 times weaker than on Earth.
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 following the departure of Russian Soyuz rockets from Kourou, cumulative delays of Ariane 6 and the failure of the first commercial flight of Vega C.
This is the penultimate flight of an Ariane 5 rocket, before the arrival of Ariane 6 scheduled for the end of 2023.
