On Thursday, Europe’s JUICE spacecraft will embark on a mission to explore the icy moons of Jupiter, marking a new chapter in humanity’s quest for extraterrestrial life.
As Europe’s JUICE spacecraft takes off on Thursday to investigate Jupiter’s icy moons, it marks a new era in the search for extraterrestrial life. These moons, which were discovered by Galileo Galilei over 400 years ago, were previously ignored as potential hosts of life due to their distance from the Sun. However, recent advancements in space exploration have led scientists to consider the possibility of these ice-covered moons containing vast oceans of liquid water beneath their surfaces, potentially harboring alien life within our own Solar System.
According to French astrophysicist Athena Coustenis, who is one of the scientific leads of the European Space Agency’s JUICE mission, until recently, scientists thought that the Solar System’s habitable zone ended at Mars. However, NASA’s Galileo probe to Jupiter in 1995 and the more recent Cassini spacecraft’s trip to Saturn prompted scientists to broaden their perspectives. The gas giant planets themselves were not viable, but their icy moons, such as Jupiter’s Europa and Ganymede and Saturn’s Enceladus and Titan, offered fresh hope for the existence of nearby life. These icy moons are believed to have vast oceans of liquid water under their icy surfaces, which is a vital component for life as we know it. According to Nicolas Altobelli, a JUICE project scientist at ESA, exploring habitats beyond the frost line between Mars and Jupiter will be a first for humans. Temperatures below the frost line are so low that liquid water can no longer exist on the surface. Altobelli informed AFP earlier this year about the challenges of the mission.
‘Gigantic’ ocean
On Thursday, the Jupiter Icy Moons Explorer (JUICE) mission embarks on an eight-year journey through space, launching from Europe’s spaceport in Kourou, French Guiana. Its destination is Jupiter, where it will enter the planet’s orbit by July 2031, and then investigate the icy moons of Ganymede, Europa, and Callisto. JUICE will be the first spacecraft to enter Ganymede’s orbit in 2034, making history. Unlike other missions that focus on finding signs of ancient life, JUICE scientists hope to discover living organisms on Jupiter’s icy moons. Ganymede is the only moon in the Solar System with its own magnetic field, protecting it from harmful radiation, and providing a stable environment for life. Jupiter’s gravity could serve as a power source for these moons, in the absence of energy from the Sun.
The moons of Jupiter are warmed by tidal heating, which generates a force that keeps the water under their icy surface liquid. According to Carole Larigauderie, JUICE project head at French space agency CNES, Ganymede’s ocean is “gigantic” and located between two thick layers of ice that are dozens of kilometres deep. On Earth, life forms have been found in the deepest abysses, and this raises the possibility that life could exist elsewhere without sunlight, such as on Ganymede. However, the presence of necessary chemical elements and nutrients in Ganymede’s ocean is still uncertain. French astrophysicist Athena Coustenis asks, “The big question is therefore whether Ganymede’s ocean contains” the necessary elements for life, and whether it can absorb nutrients from the moon’s surface.
Not alone
UICE’s suite of scientific instruments will investigate Ganymede’s ocean, aiming to determine its composition, distance from the surface, and depth.
Over an eight-month period, the ESA’s €1.6 billion ($1.7 billion) spacecraft will orbit Ganymede, approaching as near as 200 kilometers (125 miles) from the moon, while being shielded from radiation.
Meanwhile, NASA’s Europa Clipper mission is set to launch in October 2024, taking a faster trajectory to Jupiter and arriving at Europa in 2030.
If one or more of Jupiter’s moons meet all the conditions for hosting life, the “next logical step” would be to send a spacecraft to land on their surface, stated Cyril Cavel, the JUICE project manager at manufacturer Airbus, even though there are currently no plans for such a mission. Such a mission would be a “part of the dream” to unequivocally prove the existence of extraterrestrial life.
