Today, Jupiter is approximately 891 million kilometres away from the Earth, it is composed mostly of gas and is more than twice the size of all the other planets in our solar system combined. Discovered in 1610 by Galileo Galilei, such a distant world appears inhospitable and profoundly foreign to life as we know it.
Jupiter’s moons, however, are quite literally a whole new world. According to NASA, Jupiter has between 80 and 95 known moons – three of which the European Space Agency (ESA) is now seeking to understand.
On Friday 14th April, the EAS launched the Jupiter Icy Moons Explorer (JUICE) from French Guiana, commencing its eight-year voyage to some of Jupiter’s icy and largest moons – Europa, Callisto, and Ganymede.
These moons are ocean-bearing, meaning they harbour the most crucial ingredient for life. The ESA say that the point of their mission is to “characterise these moons with a powerful suite of remote sensing, geophysical and in situ instruments to discover more about these compelling destinations as potential habitats for past or present life.”
Once JUICE enters Jupiter’s orbit, the ESA hopes to more closely monitor the magnetic, radioactive and plasmic environments of Jupiter and use their findings as an “archetype” for other giant gas systems in the Universe.
Less than one hour to launch! 🤞
📹 Watch a one-minute summary of the #ESAJuice mission! 😅 pic.twitter.com/V3IkBZl8VA
— ESA's Juice mission (@ESA_JUICE) April 14, 2023
The Journey to Jupiter
The orbiter was launched Ariane 5 rocket which has been operational since 1996 and was also used to launch the James Webb Telescope in 2021.
In order to reach Jupiter, JUICE will complete four gravity-assist flybys to slingshot the spacecraft towards the outer Solar System. The flyby uses the orbit of another celestial body to increase the velocity of the spacecraft, propelling them through the Solar System.
The first of these flybys is due to happen in April 2024 when JUICE will undertake a lunar-Earth gravity assist – a flyby of the moon followed a day and half later by a flyby of the Earth. This will be the first time a flyby like this has been accomplished in space exploration history.
The ESA expects JUICE to face numerous challenges along the way: shields will protect the spacecraft’s electronics from extreme radiation levels near Jupiter. There are also multiple layers of insulation to regulate internal temperatures. Externally, JUICE may experience temperatures of over 250℃ when nearing Venus for a slingshot and temperatures of -230℃ near Jupiter.
Ignacio Tanco, the ESA’s JUICE operations manager says “to fly such a complex path from such an enormous distance – and vitally, to get JUICE’s valuable data home to Earth – will require precise navigation techniques, reliant on deep space antennas in Spain, Argentina and Australia, all controlled remotely from ESOC.”
What's next for #ESAJuice?
🔜Over the next 2️⃣ weeks booms & antennas will be deployed
🔍Over the next 3️⃣ months the science instruments will be checked out
🌍⤴️Over the next 4️⃣ years flybys of Earth & Venus
🧡Arrival Jupiter in 2031!
🗺️Follow the journey https://t.co/TBFlc4dccd pic.twitter.com/KvnPgmmWxI— ESA's Juice mission (@ESA_JUICE) April 16, 2023
Jupiter’s moons
Europa is thought to be the moon with the highest likelihood of hosting environments suited to life.
Hidden beneath an icy surface is a salty water ocean believed to contain almost double the amount of water found here on Earth. Europa is also thought to have a similar structure to Earth with a rocky mantle and iron core.
According to NASA, existing evidence supports the theory that Europa’s oceans are in contact with rock – life as we understand it needs liquid water, an energy source, and organic compounds. Europa possibly has all three and its ocean may have existed long enough for life to evolve there.
Ganymede is the largest moon in our Solar System and salt water is thought to exist here underground – possibly in layers separated by ice.
It’s also the only moon to have its own magnetic field, manipulating atmospheric gas around the poles and creating auroras like we have on Earth. There is also evidence of an oxygen atmosphere.
Callisto is the most cratered object in the Solar System but images show bright white patches of snow on the surface and darker areas where ice once eroded the ground.
Related Articles: Space Junk: Has Earth’s Orbit Become Our Scrap Yard?, NASA’s Return to the Moon on Hold, Our Outer Space Future: Is There a Better Way Out?, NASA Unveils Deepest-Ever Images of the Universe.
Thought to be inactive, data gathered in 1990 suggests that Callisto might also have a salty ocean beneath the surface but very deep down. However, this does not dishearten scientists as anywhere that water and rock interact produces an environment where life is possible.
With all three moons thought to have suitable conditions for life, the ESA will study the moons as potential habitats – working to understand the conditions for planet formation and life as well as the wider workings of the Solar System.
What do scientists expect to find?
Whilst Europa, Ganymede and Callisto are thought to have environments conducive to life, scientists do not believe that they will find solid evidence of organisms existing here.
Speaking to Space.com, Adam Masters, senior lecturer in space at atmospheric physics at Imperial College London and member of a team responsible for building a specific instrument on JUICE, said: “if life exists on these moons, we expect it to be in the water and that’s very hard to access.”
He goes on to add “We don’t expect life on the surface of these moons and it’s not feasible yet to go down [underneath the ice crust] to where there might be life.”
Instead, JUICE will be monitoring the moons from several hundred miles away, mostly monitoring the environmental conditions to gain insight into the composition of these oceans and how they might have formed.
We might not know for decades more whether our Solar System hosts life outside of Earth but for the ESA, JUICE marks the first Large-class mission as part of their Cosmic Vision 2015-2025 programme which seeks to better understand the Solar System through a series of questions.
There seems to be a wider aim to JUICE’s mission other than the discovery of life, according to Carole Mundell, the ESA’s Director of Science.
The data retrieved by JUICE will better allow the global science community “to dig in and uncover the mysteries of the jovian system, explore the nature and habitability of oceans on other worlds and answer questions yet unasked by future generations of scientists.”
Editor’s Note: The opinions expressed here by the authors are their own, not those of Impakter.com — In the Featured Photo: The Jupiter family, including Europa, Ganymede and Callisto. Featured Photo Credit: Wikimedia Commons courtesy of NASA.
