The European Space Agency (ESA) Jupiter Icy Moons Explorer (JUICE) mission, scheduled to be launched on April 13, 2023 from the Center Spatial Guyanais (CSG) in Kourou, French Guiana, will aim to unravel the mysteries of the three largest icy moons of Jupiter: Ganymede, Callisto and Europa. JUICE’s suite of instruments will allow scientists to thoroughly explore and characterize the moons, each of which is believed to have large pools of liquid water beneath its surface, creating potentially habitable environments for life.
After completing construction and testing at an Airbus facility in Toulouse, France, JUICE was shipped to CSG in French Guiana, where it arrived on February 9, 2023 and is currently being prepared for its April launch.
Many milestones and goals lie ahead for the JUICE teams – both before and after launch. NASASpaceflight conducted a one-on-one interview with Cyril Cavel, JUICE program manager at Airbus Defense and Space in Toulouse, France, for more information on the mission and the progress of launch operations in French Guiana.
The history of JUICE
JUICE began as a reformatted version of ESA’s Jupiter-Ganymede orbiter mission, which was part of the canceled NASA/ESA proposal for the Europa Jupiter System Mission – Laplace (EJSM-Laplace). After the announcement of JUICE’s mission proposal, it became a candidate for the L-class mission of ESA’s Cosmic Vision program, which aims to select and launch spacecraft for solar system exploration and astronomy.
JUICE was selected as Cosmic Vision’s first L-class (L1) mission on May 2, 2012. Spacecraft payload selection took place in February 2013 and Airbus Defense and Space was selected as JUICE’s prime contractor in July 2015. As prime contractor, Airbus would be responsible for the development, construction and testing of JUICE, all carried out at the Airbus facility in Toulouse, France.
Rendering of the JUICE spaceship. (Source: ESA)
In March 2016, the review of the mission and system requirements was completed, allowing Airbus to begin the design and construction phase of the mission. Meanwhile, the 2017 spacecraft and instrumentation preliminary design reviews and ground segment requirements review were completed, which was completed in December 2018 the following year.
The design phase of the JUICE mission accelerated significantly in 2019, with the spacecraft critical design review completing in March and the scientific ground segment design review the following month. The assembly of the JUICE flight model began in September 2019, which officially heralded the construction phase of the mission.
The effects of the COVID-19 pandemic then significantly delayed construction of the spacecraft, with final integration and testing not beginning until mid-2022. Meanwhile, ground segment readiness verification was only completed in November, and JUICE’s qualification and acceptance verification was finally completed on January 18, 2023 – completing the construction and testing phase of the mission.
Start processing of JUICE
Upon arrival at CSG, the spacecraft was moved to the payload preparation facility and unpacked so launch procedures could begin.
“We also conduct many tests, leak tests, electrical checks and performance tests to verify that the chemical propulsion subsystem is still functioning properly after transport and at the very end of all spacecraft environmental testing campaigns in France. ‘ Cavel said.
These types of post-shipment post-verification checks are common on various satellites.
🛰️🗞️ Juicy news from French Guiana, also on Saturday! #ESAJuice Spaceship almost in launch configuration, ready for refueling…. 👇 pic.twitter.com/Ozup11Oj2K
— ESA’s JUICE mission (@ESA_JUICE) March 11, 2023
“In parallel, we’re running a series of final functional tests on the spacecraft – so we’re testing all functional chains of the platform and the instruments to verify that we’re ready for launch,” added Cavel. “We will do that [until about mid-March].”
As part of his position as Project Manager of JUICE, Cavel oversaw the construction, testing and shipping of JUICE. He is currently based in French Guiana closely overseeing JUICE’s launch processing procedures and ultimately the launch itself.
One such process that Cavel will oversee in French Guiana is the transfer of JUICE from one processing facility to another. Once the teams have finished preparing JUICE in the Payload Preparation Facility, the spacecraft must be moved to the Hazardous Processing Facility.
“About mid-March we will be moving here at CSG to another facility called the Hazardous Processing Facility or HPF. This is the facility where we will refuel the spacecraft. We need to load three and a half tons of fuel into our large fuel tanks, which are located in the spacecraft’s central cylinder.”
“This will be carried out by our subcontractor ArianeGroup. It’s a dangerous activity that will last about two weeks,” Cavel said.

The Ariane 5 JUICE upper stage will be on its flight into orbit in April. (Source: ESA/CNES/Arianespace/Optique video du CSG – S. Martin)
Once all the necessary propellants are loaded into JUICE, the spacecraft will be taken to the Ariane 5 rocket processing facility, where it will be connected to the launch vehicle’s upper stage.
“And then we will proceed with connecting the spacecraft to the launcher interface adapter. This is the beginning of what we call “combined operations”. We will hit and process the launcher [the two vehicles] parallel to. Then comes the final preparation of the spacecraft and launch vehicle, including mating, fairing encapsulation and the very last activities before the final launch countdown.”
When launch day arrives, currently scheduled for April 13, 2023, JUICE will be launched into space on an Ariane 5 rocket from Pad ELA-3, in what will be the penultimate Ariane 5 launch. After separating from the top of the Ariane 5 upper stage, the spacecraft will embark on an eight-year journey to the Jupiter system.
During JUICE’s coastal phase, the spacecraft will make a total of four flybys — one of the Earth-Moon system in August 2024, one of Venus in August 2025, and then two more of Earth in September 2026 and January 2029. Each of these flybys will JUICE use the gravity of either Earth-Moon, Venus, or Earth to increase its speed without the use of propellants.
Upon completion of the fourth and final flyby, JUICE’s aphelion (the most distant point in its orbit from the Sun) will reach the plane of Jupiter’s orbit. These maneuvers are called gravity assist and are used to increase a spacecraft’s speed and thus change its overall orbit.
Assuming an on-time launch and successful completion of all four gravity assists, JUICE will arrive at Jupiter in July 2031 and conduct its first flyby of an icy moon, Ganymede, shortly after entering Jupiter’s sphere of influence.
Over the next three years, JUICE will conduct multiple flybys of Ganymede, Callisto and Europa, eventually culminating with the spacecraft entering orbit around Ganymede in December 2034, where it will spend the remainder of its mission.
JUICE will eventually use all of its propellants to fly away from Ganymede in late 2035 and hit the moon’s surface shortly thereafter.
(Main image: JUICE being unpacked after its delivery to CSG in French Guiana. Credit: ESA-CNES-Arianespace/Optique video du CSG/S. Martin)