April 14, 2023
The journey to Jupiter has begun. The European Space Agency’s unmanned spacecraft JUICE (short for JUpiter ICy moons Explorer) recently launched (13 April) from Europe’s Spaceport in French Guiana.
JUICE’s voyage, the ESA’s most ambitious mission to date, will be particularly lengthy: Upon reaching Jupiter’s orbit by 2031, it will embark on a four-year mission to investigate three of Jupiter’s moons – Callisto, Europa and Ganymede – as well as the composition of Jupiter’s atmosphere.
An in-depth exploration of the planet’s atmosphere will be made possible by the contribution of Professor Yohai Kaspi and Dr Eli Galanti, both of the Weizmann Institute of Science’s Earth and Planetary Sciences Department and members of JUICE’s Science Team.
They are in charge of one of the mission’s key experiments and will use their own Ultra Stable Oscillator, a device that will allow them to probe Jupiter’s atmosphere. Not only was the device – the most precise instrument of its kind in the world – customized by Israeli scientists, it was manufactured by the Israeli company AccuBeat; in addition, the endeavour was funded by the Israel Space Agency. All this makes it a landmark achievement: the first time an entirely Israeli invention will leave Earth’s vicinity.
“This is not our first involvement in international space missions, but the fact that this is a completely Israeli creation makes it very special for us,” Kaspi said, as The Weizmann team began working on the project back in 2013, when the ESA announced the mission.
“When I first approached the Israel Space Agency with the idea of building the oscillator, this seemed an impossible task, but the commitment of the agency and the synergy of industry and academia made this happen,” he added.
Uri Oron, Director of the Israel Space Agency at the Ministry of Innovation, Science and Technology, said The Israel Space Agency is proud to be taking part in the European Space Agency’s flagship mission, both in terms of its engineering and technology, and in terms of its research.
“Without doubt, the research to be conducted at the Weizmann Institute will constitute a key component in the mission’s research program, and will continue to advance space research in Israel and position it among the global leaders in the field,” he said.
Only after launch will the spacecraft spread its solar wings, as well as the sensors and antennas needed for the long journey to Jupiter (Animation courtesy of the ESA)
Traveling to Jupiter – which is about 800 million kilometres away – is not an easy feat, by any means. On its way to the giant gas planet, JUICE will perform a flyby of Venus and three flybys of Earth before gaining enough momentum – in what’s known as the slingshot effect – to make its way to Jupiter. The spacecraft’s estimated time of arrival in July 2031 will mark the beginning of its four-year expedition.
“My hair will be completely grey by the time JUICE reaches Jupiter,” said Kaspi.
Because of the long journey ahead, the aptly-named Ultra Stable Oscillator had to be extraordinarily stable, designed to survive crossing the vast distances of the cosmos.
“It’s a unique achievement. The oscillator was constructed to be extremely durable, yet it’s incredibly light – it weighs only two kilograms. It was a technological challenge and AccuBeat really pulled it off,” said Galanti.
Says Benny Levy, CEO of AccuBeat also added: “AccuBeat’s vast experience and knowledge helped the development of technology with unprecedented capabilities. We are proud and excited to be part of a historic research project, the results of which can very well lead to sensational discoveries in the world of science, space and humanity as a whole.”
During its time in Jupiter’s orbit, JUICE will circle the gas planet nearly 100 times, in the course of which the spacecraft will transmit a powerful signal back to Earth. The Weizmann team intends to use these opportunities to gather data on the makeup of Jupiter’s atmosphere and the conditions prevailing within, learning as much as possible by analysing the signal disparity caused by Jupiter’s occultation of JUICE.
Each orbit will present a small window of opportunity lasting a few minutes, during which the signal will pass through the atmosphere on its way back to Earth. Since each orbit will be entered from a different angle, the team plans to use the combined data to model a dynamic map of Jupiter’s entire atmosphere, thus expanding our understanding of the largest planet in the Solar System.
“In order to perform this complex experiment, we need the Ultra Stable Oscillator to be extremely accurate,” said Maria Smirnova, a graduate student in Kaspi’s lab who is taking part in the project.
“Even if it worked for 100,000 years, its oscillations would be regular to within a second.”
Furthermore, the Weizmann scientists will be participating, as part of their role in JUICE’s Science Team, in the icy moon part of JUICE’s agenda, where they will contribute their expertise in oceanic and atmospheric turbulence to, hopefully, provide insights into the oceans of Callisto, Europa and Ganymede. These three moons, which are completely covered in ice, could possibly represent the biggest repository of H2O in the Solar System. While their surface is entirely frozen, previous magnetic field measurements showed that beneath lie vast, liquid oceans. The team hopes to find out how deep these oceans are, and whether the presence of water on Jupiter’s moons spells the existence of conditions for life as we understand it.
Although JUICE’s odyssey now begins, it will be a while before we find out the answers to these almost sci-fi questions. Kaspi’s team will use this time to improve their dynamic modelling capabilities, though they can’t help but get swept up by the excitement of the launch.
“It’s not every day that hundreds of thousands of work hours boil down to a single event in which your creation gets strapped to 700 tons of jet fuel,” said Kaspi.
Professor Yohai Kaspi presents the Ultra Stable Oscillator built by AccuBeat – the most precise instrument of its kind in the world (Photo: AccuBeat)
Illustration showing the unmanned spacecraft JUICE in the vicinity of Jupiter (center). On the right: the moons Callisto and Europa; on the left: Ganymede and Io (yellow), Jupiter’s volcanically active moon that is not included in the mission’s core program (Courtesy of the ESA)
Weizmann Institute participants in the JUICE mission to Jupiter (l-r): Maria Smirnova, Professor Yohai Kaspi and Dr Eli Galanti