JUICE will be following in the footsteps of a highly successful NASA mission, the Galileo spacecraft. Big shoes to fill as Galileo, amongst many other things, discovered that Europa has an internal ocean, making it a prime candidate for life away from Earth.
Ganymede was taken from the New Horizons spacecraft as it passed by on its way to the outer solar system. It’s hoped that ESA’s JUICE spacecraft will find answers to some of the mysteries this moon possesses. NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
However, while Galileo focused on the smaller moon Europa, JUICE firmly has the largest of Jupiter’s moons, Ganymede, in its sights. The satellite is due to enter orbit of the icy moon in 2032; it will circle Ganymede, investigating the moon’s surface and magnetic field.
Ganymede is unique within the solar system, as it is the only moon that generates its magnetic field. This is particularly weird as the moon was originally thought to be too small and cold to develop such a strong field. Though some have deemed a few ways this could happen, the phenomenon that creates the magnetic field will remain a mystery until JUICE gets there.
Similar features on Ganymede (left) and Europa (right). Where it is thought that the feature on Europa has been formed from the spreading of the icy crust, it’s not so clear if the same process can happen on the older terrain of Ganymede. NASA/JPL/Brown University
Paradoxes from the magnetic field aside, the similarity of features between Europa and Ganymede also makes this moon a tempting prospect for life. JUICE will carry two cameras, one with filters, so that extra details can be picked up on the surface.
So it’s quite a wait, and I don’t know where on Earth I’ll be by 2032. But I’ll be mostly looking forward to the results of the spectrometers that JUICE will carry. Though we know the surfaces of these moons are partly made of water ice, there is thought to be a significant amount of other material. These instruments will discover what these extra materials are, which would be super if they tied up with the experiments I’m doing at the synchrotron!
