The European Space Agency’s (ESA) JUICE mission launched successfully on Friday from the European spaceport in Kourou, French Guiana after its originally-planned launch on Thursday was postponed because of poor weather.
The mission has several experiments on board, including from the Weizmann Institute of Science, as they venture on a bold new journey to Jupiter and its moons.
The JUICE (Jupiter Icy Moons Explorer) mission is the ESA’s biggest mission ever, and Israel’s participation is funded by the Israel Space Agency, which falls under the auspices of the Science and Technology Ministry. This is the first time that Israeli technology is traveling to another planet.
The probe was launched on an Ariane 5 rocket on its 900-million-kilometer journey, first doing a flyby of Venus and then three flybys of Earth. This will help the probe build up momentum for a slingshot ride to Jupiter. It is expected to arrive at Jupiter in July 2031, when it will begin its dedicated four-year mission: Circling the largest planet in the solar system nearly 100 times while studying its atmosphere as well as exploring three of its most important moons, Ganymede, Callisto and Europa.
What is Israel's role in the JUICE mission to Jupiter?
Joining the JUICE mission is a major experiment led by Prof. Yohai Kaspi and Dr. Eli Galanti from Weizmann that will analyze Jupiter’s atmosphere.
This isn’t the first time that the two researchers have been involved in space missions and Kaspi, in particular, has been noted for his research on Jupiter. In 2021, working off data from NASA’s Juno mission, he was able to produce the first in-depth measurement of Jupiter’s famous red spot, gathering new information on the formation of storms on the planet. Now, he and Galanti are hoping to make a similar breakthrough.
“What we’re doing is sending a radio beam from the spacecraft to Earth and when it goes through the atmosphere, it gets distorted which lets us get temperature readings,” Kaspi told The Jerusalem Post.
“We will build a 3D map of Jupiter’s temperature, which no one has ever done before,” he said, noting that the JUICE mission will be complimentary to the data gleaned from Juno.
"We will build a 3D map of Jupiter's temperature, which no one has ever done before."
Prof. Yohai Kaspi
The hoped-for new data will be helped by the unique orbit of the JUICE probe.
“JUICE’s main goal is to study the icy moons, so the orbit is going to be very unique, meaning that we can get these samples over different locations on Jupiter,” Kaspi said. “We’re taking advantage of that to be able to study the atmosphere itself and beneath it.”
It can also help to solve the mystery of whether Jupiter has a solid core, as contrary to previous beliefs that gas giants such as Jupiter have solid cores, some scientists now think this to be less likely.
“We think it might have a diffused core or fuzzy core, something more like mixed plasma rather than rock,” Kaspi said.
He also noted that it could help shed light on the origins of the solar system itself, since Jupiter is the oldest planet.
The Jerusalem-made Israeli clock going to Jupiter
Finding answers to these questions will be made possible through the use of an Ultra Stable Oscillator, a highly complex and sensitive clock that will facilitate some of the most precise measurements ever made.
“It’s so accurate that if you ran it for 100,000 years, it would only lose less than a second,” Kaspi said.
The way this instrument was built in the first place was almost by accident.
“The oscillator should have come from NASA,” Kaspi explained, noting that the JUICE mission was originally a joint effort between the ESA and NASA. “But then NASA had budget cuts and decided to pull out. So, we started looking for another way to make one, and pretty much by chance, we bumped into the Israeli company AccuBeat.”
Based in Jerusalem’s Har Hotzvim Industrial Zone, AccuBeat is one of the few companies in the world that make atomic clocks. However, at that point, it wasn’t involved in space technology and made only clocks for civilian and military use.
“AccuBeat’s vast experience and knowledge helped the development of technology with unprecedented capabilities,” said AccuBeatCEO Benny Levy. “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.”
While this is the first time Israel-made technology is going to another planet, it is also a landmark moment for the ESA.
“Until now, the outer solar system was only NASA’s territory, but now the ESA is going to Jupiter on an independent mission,” Kaspi said.
Studying the mysteries of Jupiter's icy moons and unforeseen NASA joint experiments
In addition to studying Jupiter’s atmosphere, the Weizmann scientists will also be helping study the moons.
“The moons have an ionosphere, think of it as a very thin layer of atmosphere. It’s so thin, that it’s more like ions floating around in space. We’ll be studying those,” Kaspi explained.
“The icy moons might also have some plumes of water spitting out into space from subterranean oceans, and JUICE is trying to measure those too. The main mission is to characterize the oceans of water.”
Jupiter’s moons have long been the subject of great curiosity and the three being observed, in particular, are completely frozen over but beneath that icy layer, there are believed to be vast oceans of still liquid water. This is supported by prior magnetic field measurements. In fact, these planets could possess the solar system’s single largest quantity of water.
And since liquid oceans are also in the presence of a heat source, it poses a tantalizing possibility of finding alien life – or at the very least, of discovering whether the moons have the ability to support life.
NASA has planned a mission to Europa for the same reason. The Europa Clipper, organized after NASA pulled out of JUICE, is set to be launched in October 2024 – though because of the different rocket used and the more direct flight path, it may arrive in the Jovian system before JUICE.
This would be a further groundbreaking prospect as it means that for the first time, there will be two probes in the vicinity of Jupiter at the same time.
“These outer-solar system probes usually only happen around once per decade,” Kaspi said. “This has actually turned out interesting because if you have two points of view around Jupiter, you can do some unique experiments.
“One of the things we’re going to be doing until then are joint science missions. None of this was originally planned, but now we can initiate new experiments.”