The European mission Juice hopes to achieve its ends. 24 hours after its postponement due to bad weather, the space probe is due to launch on Friday April 14 in the direction of Jupiter and its icy moons, in search of habitable environments for extraterrestrial life.
Liftoff from the Kourou spaceport in French Guiana is scheduled for 12:14 p.m. GMT (2:14 p.m. in Paris), half an hour earlier than the scheduled takeoff time during the first attempt.
On Thursday, the teams from the Guiana Space Center interrupted operations because of a risk of lightning, while several personalities, including the King of the Belgians Philippe and the French astronauts Thomas Pesquet and German Matthias Maurer, had come to attend the launch from the Jupiter's control room.
A few minutes before the final count, "a large cloud mass approached and we put a 'weather red', because we absolutely could not proceed with the launch because of this risk of lightning strikes", explains to Agence France -Press Stéphane Israël, the president of 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 added.
If the relatively predictable altitude winds are announced as green for this Friday, "we will have to continue to monitor the risk of lightning until the last moment", warns Stéphane Israël.
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. According to the flight schedule, the six-ton probe is to separate from the rocket 27 minutes after liftoff, at an altitude of about 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). While leaving to explore Jupiter and its icy moons, the probe is 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, after an eventful journey.
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 four hundred years: volcanic Io and her three icy 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. However, only water in a liquid state makes life possible.
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 could develop there. "It's the most complex probe ever sent to Jupiter," said Philippe Baptiste, president of the Center National d'Etudes Spatiales (CNES). Designed by Airbus, Juice carries ten scientific instruments (optical camera, imaging spectrometer, radar, altimeter, magnetometer, etc.).
It is also equipped with huge solar panels of 85 m2 (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 after 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.
