Set for launch from the Centre Spatial Guyanais (CSG) in Kourou, French Guiana, on April 13, 2023, the European Space Agency’s (ESA’s) Jupiter Icy Moons Explorer (JUICE) mission will aim to uncover the secrets of Jupiter’s three largest icy moons: Ganymede, Callisto, and Europa. JUICE’s suite of instruments will allow scientists to thoroughly explore and characterize the moons, each of which is thought to feature large bodies of liquid water beneath their surfaces — creating potentially habitable environments for life.
Following the completion of construction and testing at an Airbus facility in Toulouse, France, JUICE was shipped to the CSG in French Guiana, where it arrived on Feb. 9, 2023, and is currently being processed for its launch in April.
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 Defence and Space in Toulouse, France, for more information on the mission and how launch processing is progressing in French Guiana.
JUICE began as a re-formatted version of ESA’s Jupiter Ganymede Orbiter mission, which was a component of the canceled NASA/ESA Europa Jupiter System Mission – Laplace (EJSM-Laplace) proposal. Following 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 solar system exploration and astronomy spacecraft.
JUICE was selected as the first L-class mission (L1) of Cosmic Vision on May 2, 2012. Spacecraft payload selection took place in Feb. 2013, and Airbus Defence and Space was selected as JUICE’s prime contractor in July 2015. As prime contractor, Airbus would be responsible for designing, constructing, and testing JUICE, all of which was done at Airbus’ facility in Toulouse, France.
In March 2016, the Mission and System Requirements Review was completed, allowing Airbus to begin the design and construction phase of the mission. Meanwhile, 2017 saw the spacecraft and instrument preliminary design reviews, as well as the Ground Segment Requirements Review, the latter of which was completed the following year in Dec. 2018.
The design phase of JUICE’s mission ramped up significantly in 2019, with the Spacecraft Critical Design Review completed in March and the Science Ground Segment Design Review completed the following month. In Sept. 2019, the assembly of JUICE’s flight model began, officially kicking off the construction phase of the mission.
Impacts from the COVID-19 pandemic then significantly delayed the spacecraft’s construction, with final integration and testing only beginning in mid-2022. Meanwhile, the Ground Segment Readiness Review was only completed in November, and JUICE’s Qualification and Acceptance Review was finally finished on Jan. 18, 2023 — bringing the construction and testing phases of the mission to a close.
JUICE’s Launch Processing
After arriving at the CSG, the spacecraft was moved to the Payload Preparation Facility and unpacked, allowing launch processing procedures to begin.
“We’re also doing a lot of tests, leakage tests, electrical checkouts, and performance tests in order to verify that after transportation and at the very end of all spacecraft environmental test campaigns in France, the Chemical Propulsion Subsystem is still working fine,” said Cavel.
These types of post-shipment re-verification checks are common with various satellites.
— ESA's Juice mission (@ESA_JUICE) March 11, 2023
“In parallel to that, we are doing a number of final functional tests on the spacecraft — so exercising all the functional chains of the platform and the instruments in order to verify that we are good to go,” added Cavel. “We’ll be doing this [until about mid-March].”
As part of his position as JUICE’s project manager, Cavel oversaw the construction, testing, and shipment of JUICE. He is currently stationed in French Guiana, where he is closely monitoring JUICE’s launch processing procedures and, eventually, the launch itself.
One such procedure Cavel will oversee in French Guiana is the transfer of JUICE from one processing facility to another. Once teams finish preparing JUICE in the Payload Preparation Facility, the spacecraft will need to be moved to the Hazardous Processing Facility.
“Around mid-March, we will move to another facility here at CSG called the Hazardous Processing Facility or HPF. This is the facility where we will fuel the spacecraft. We have to load three and a half tons of fuel inside our big propellant tanks, which are inside the central cylinder of the spacecraft.”
“This is performed by our subcontractor, ArianeGroup. It’s a hazardous activity that will take approximately two weeks,” said Cavel.
Once all of the needed propellants are loaded into JUICE, the spacecraft will then be moved to the Ariane 5 rocket’s processing facility, where it will be mated to the launcher’s upper stage.
“And then we will proceed to the mating of the spacecraft to the launcher interface adapter. This is the start of what we call ‘combined operations.’ We will meet the launcher and process [the two vehicles] in parallel. So final preparation of the spacecraft and launcher occurs then, including mating, fairing encapsulation, and the very final activities before the final launch countdown.”
When launch day arrives, currently slated for April 13, 2023, JUICE will be lofted into space atop an Ariane 5 rocket from pad ELA-3, in what will be the penultimate launch of an Ariane 5. After separating from the top of the Ariane 5 upper stage, the spacecraft will begin an eight-year journey to the Jovian system.
During JUICE’s coast phase, the spacecraft will perform a total of four flybys — one of the Earth-Moon system in Aug. 2024, one of Venus in Aug. 2025, and then two more of Earth in Sept. 2026 and Jan. 2029. Each of these flybys will see JUICE utilize the gravity of either Earth-Moon, Venus, or Earth to increase its velocity without the use of propellants.
At the completion of the fourth and final flyby, JUICE’s aphelion (the farthest point from the Sun in its orbit) will reach Jupiter’s orbital plane. These maneuvers are called gravity assists and serve to increase a spacecraft’s velocity and, thus, alter its overall orbit.
Assuming an on-time launch and successful completion of all four gravity assists, JUICE will arrive at Jupiter in July 2031, performing its first flyby of an icy moon, Ganymede, shortly after entering Jupiter’s sphere of influence.
Over the next three years, JUICE will perform multiple flybys of Ganymede, Callisto, and Europa, ultimately culminating with the spacecraft entering orbit around Ganymede in December 2034, where it will live out the remainder of its mission.
JUICE will eventually use all of its propellants to deorbit itself from Ganymede in late 2035, impacting the surface of the moon shortly after.
(Lead image: JUICE is unpacked following its delivery to the CSG in French Guiana. Credit: ESA-CNES-Arianespace/Optique video du CSG/S. Martin)