The European Space Agency’s Juice probe is preparing to leave Toulouse, where it has undergone a long test campaign. Take-off is scheduled from the Guiana Space Center from April 10. Reporting in a clean room. This is THE big mission of this space year 2023. Guyana will roar with the penultimate launch of the Ariane 5 rocket, destination Jupiter, more precisely its moon Ganymede. It is a journey of almost eight years that awaits the probe which, once arrived, will operate 35 flybys of the icy moons of Jupiter. The trip promises to be full of challenges. The probe will have to face very cold or very hot environments, in particular during the flybys of planets planned during its journey. On the program: a first flyby of the Earth in August 2024 with, shortly before, the use of the Moon as gravitational assistance, then a flyby of Venus in August 2025, two more flybys of the Earth in September 2026 and August 2029, and finally an arrival in the Jovian system in July 2031. This is where it will perform 35 flybys of the moons Europa, Callisto and Ganymede before going into orbit around the latter in December 2034. Fifteen days in an empty tank for of the last thermal testsThe thermal tests had first started at the beginning of 2021 at the Estec center of the ESA in the Netherlands but, as several scientific instruments were not yet available, the tests were redone from the beginning in Toulouse at the end of 2022. “The space environment for Juice is very complicated because we go very close to the Sun during the planetary acceleration phases at the start of the mission (…) and at Jupiter, we are very far from the Sun”, specifies Frédéric Faye, chief engineer Juice at Airbus Defense & Space. The flyby of Venus will force Juice to survive high temperatures while the long distance into Jupiter and the Sun (five times farther than Earth) will subject the probe to a very cold environment. The thermal tests complete the test campaign carried out by the probe since August 2021 in Toulouse. They were of different natures: thermal, electrical, magnetic, mechanical, acoustic (vibrations and communication). Each time, before and after an environmental test, Juice underwent functional testing to see if she hadn’t been impacted by the test. In terms of mechanical and electrical tests, the teams had tested the deployment of gigantic solar panels, as well as the electrical power they provide. Final earthbound imminentWhat’s left to do now that Juice is ready to depart? First, the teams will reattach the solar panels that had been detached for thermal testing. Then, Juice will be stored in a specialized container and will be transported from the Airbus premises to Blagnac airport. It was there that an Antonov plane was waiting for him to be transported to Kourou. Juice is not leaving alone, multiple test “berries” will leave with her for Guyana, it’s quite a logistics! Once in Kourou, Juice will be installed and tested in a payload preparation building at CSG. In particular, the teams will carry out several tests to see if the probe has suffered any damage during its trip from Toulouse. Refueling is scheduled for mid-March. Nearly 3,500 tonnes of propellant will fill the tanks. Combined tests (probe + launcher) are also planned. Finally, Juice will be installed under the fairing of Ariane 5 for takeoff scheduled between April 10 and 30. If ever imponderables arise causing this window of opportunity to be missed, another is scheduled for August. The Long Journey to JupiterJuice will not sit idle on its journey. Several maneuvers are planned, in particular during flybys of the planets and the Moon, which will be used as gravitational assistance to catapult the probe and make it gain more speed without spending too much fuel. During the overflights, the scientific instruments will be functional and tested, but that’s not all. Giuseppe Sarri, Juice project manager at ESA, reminds us: “Each year, we will take two weeks to turn on all the instruments to check that they are still working, and we do small calibration tests (…) We must keep the probe alive during its journey. »