The excitement is high: the Juice (JUpiter ICy moons Explorer) spacecraft is scheduled to begin its journey to Jupiter aboard an ARIANE 5 rocket from Europe’s Spaceport in Kourou, French Guiana on Thursday, April 13, 2023 at 2:15 p.m. After an almost eight-year journey, Juice will arrive at Jupiter to explore the largest planet in our solar system and three of its more than 80 moons. These are the icy dark worlds Ganymede, Callisto and Europa, ocean worlds where the average surface temperature is below minus 140 degrees Celsius. Ten instruments are on board Juice. The University of Bern is contributing the NIM mass spectrometer (which is part of the Particle Environment Package PEP) to the mission and is involved in two other instruments: the SWI Sub-millimeter Wave Instrument and the GALA Laser Altimeter. 

A lot of time usually passes between the idea for a space mission and its implementation. At the University of Bern, there are some people who have been involved with Juice from the very beginning. One of them is Yann Alibert, now co-director of the local Center for Space and Habitability. For him, the University of Bern’s prominent involvement in Juice is a logical consequence of its long tradition and proven expertise in space research: “The University of Bern was already involved in the first moon landing with the solar wind composition experiment. Since then, we have been regularly participating in space missions by the major space organizations, such as ESA, NASA and JAXA,” says Alibert.

As a young postdoc, Alibert was involved in a proposal to ESA for a space mission to explore the Jupiter system. ESA had issued a call for mission proposals for its Cosmic Vision 2015-2025 space mission program in March 2007. At the time, Alibert was working on theoretical models of the formation of moons as well as Jupiter and Saturn. “Back then, we named our proposed mission after the French scientist Pierre-Simon Laplace. He was one of the first to suggest that planetary systems could form in a disk around the sun,” Alibert recounts. The LAPLACE proposal was selected by ESA and initially developed into the mission concept called EJSM (Europa-Jupiter System Mission) in collaboration with NASA. Building on this, the LAPLACE proposal was eventually refined by ESA into the Juice space mission. “So, in a way, Juice is the grandchild of LAPLACE,” Alibert explains, laughing. “The fact that our ‘idea’ is now flying to Jupiter makes me very proud, of course!”

Audrey Vorburger is the deputy co-principal investigator of the Particle Environment Package (PEP) and the lead scientist for one of PEP’s six instruments, the NIM mass spectrometer. NIM will one day study the chemical and isotopic composition and distribution of particles in the atmospheres of Jupiter’s icy moons as well as the physical parameters of the moons’ atmospheres. “Back in December 2009, I attended the very first PEP meeting as a member of the PEP team. We were then delighted to see ESA announce in May 2012 that Juice had been selected for implementation, and in February 2013 that PEP had been selected for the journey to Jupiter,” says Vorburger.

At the time when the respective Juice instrument teams were able to designate science co-investigators, Vorburger was analyzing the newly acquired data from the energetic neutral particle instrument CENA on board Chandrayaan-1 (India’s first mission to the moon) and working extensively on planetary atmospheres. “Since this gave me the perfect qualifications, I was appointed as one of the two science co-investigators for the NIM mass spectrometer,” she recalls.

For Vorburger, Juice is a dream come true: “It is a unique feeling to know that the instrument you are holding in your hand will one day fly into space and provide us with new insights into our universe.” Asked about her personal highlights during the project, she replies: “They are still to come: I am of course looking forward to the imminent launch of JUICE and the moment when we know that Juice is now safely on its way to the Jupiter system; and then of course to the first scientific data that our instruments will provide us with.” With regard to space research at the University of Bern, Vorburger says, “Entire missions are created at the University of Bern, from the vision, conceptualization and construction, to data analysis. And science and technology always go hand in hand. Science is being lived here!”

André Galli has been on the Juice team for a good ten years, pretty much since the moment ESA selected the Juice mission and confirmed that the University of Bern would be involved in the space mission to Jupiter. Galli is the project scientist for the NIM mass spectrometer. He explains, “I am involved in planning NIM’s measurements. I am conducting research in the lab and in theory for this so we have an idea of what to expect in terms of measurements in the future.”

When Galli joined the Juice team, he was a member of Professor Peter Wurz’s research team and had already been involved in space missions to Mars, Venus and in missions conducting solar wind research. For Galli, too, taking part in space missions was a long-held wish: “Ever since I was a teenager observing the planets and stars from a hill in the Emmental, I’ve been dying to be involved in a space mission.”

Because of the scale and complexity of space missions like Juice, international collaboration is essential: the budget required usually far exceeds what any single country (except perhaps the U.S.) can provide for such a complex mission, and the necessary expertise usually cannot be found in any single country either. Working in such large international teams over decades is exciting, but also demanding, as Galli explains: “It also requires frustration tolerance and perseverance from everyone involved. As a long-distance runner, I have just the right prerequisites for this.”

Someone who joined the Juice team later is the current NIM project manager Andreas Riedo. “I had just returned from my Einstein fellowship in Berlin in 2020. The project manager at the time, Davide Lasi, took a job in the U.S., and that’s when Professor Peter Wurz approached me and asked if I would be interested in joining Juice during this exciting phase.” Riedo had repeatedly been involved in space missions since his master’s degree: “But with the Juice job offer, I was immediately catapulted to the front line of space missions. Which was just perfect!”

He also talks about the highly complex international collaboration: “At the University of Bern, we were responsible for the integration and testing of three other Juice instruments, known as the PEP-Lo NU system, with contributions from Germany, Finland, Sweden, Hungary. All the work is thus extremely international, and all the cogs have to run in sync with each other for us to be able to deliver good work.” This is very complex, but makes the work exceptionally exciting.

“High-tech instruments for space research have been developed and built at the University of Bern for decades,” Riedo raves: “Which is why we built a unique technical environment to put such instruments through their paces.” For example, vibration tables to simulate rocket launches. Or large chambers that allow testing of how the developed systems work in space conditions.

The Juice mission aims to answer fundamental questions about the formation of planets and their moons – and it also involves the search for signs of life. Data from earlier space missions and model calculations suggest that there are subsurface oceans far below Ganymede’s and Europa’s external ice layers. Based on today’s knowledge, the oceans have all the properties that are needed for life to be created – and to exist in the long term. Riedo says: “The impact on  humans and our way of thinking, if we find signs of life? Indescribable! For the first time ever, we could say that we are not alone.”

Quelle: University of Bern

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Update: 15.03.2023

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JUICE arrives in French Guiana for launch, project manager outlines next steps

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’s History

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.

 

“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)

Quelle: NS

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Update: 31.03.2023

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Sabotaging Juice

Quelle:  ESA