For many years now, the moons of Jupiter (and Saturn) have proved mysterious, complicated and interesting to astrophysicists worldwide. The interactions between the larger moons (the largest of which is about the same size as the planet Mercury) and Jupiter prove to be of great interest, and the promise of seas and tides has attracted many scientists towards believing that there may be life beneath the surface.
Their formation also poses many questions, primed as they are most readily for a larger study. The two questions that the mission hopes to answer are these: "What are the conditions necessary to create life?" and "How does the Solar System work?"
The mission itself sends a rocket to Jupiter, and will spend three years observing the moons and their planet. The rocket shall be launched from French Guiana in 2022 and shall reach Jupiter in 2030, where it shall orbit until it is no longer of use. Its main task shall be to investigate the "Galilean Moons" - namely Ganymede, Io, Europa and Callisto. Three of the four are believed to house oceans, with Io notoriously volcanic and Callisto the most cratered object in the entire system.
The probe shall be the first to estimate the thickness of Europa's icy exterior and shall study the interior of Ganymede itself. The planet not only has a size that makes it notoriously planet-like, but has its own magnetic field too, which gives further protection to any potential life. There are many other mysteries in the so-called "waterworlds", and the hope is that the answers gained from the mission would address several further questions about the solar system as a whole and its formation.
The mission is set to cost £695 million over its lifecycle (including the rocket and satellite, manufacturing and delivery, staffing and analysis costs from today through to 2033). Though it's only going to get its final "go-ahead" in 2014, it is important that the cost is known about. NASA decided against supporting the mission by producing a companion satellite (aimed toward Europa) due to "budget concerns", but the European Space Agency still includes a number of countries in its mission statement.
Indeed of the 15 members of JUICE's Science Study Team, four are from the UK, four from France, two from Italy, two from Germany, one Spaniard and a lone Belgian. The final member, from Italy, was Angioletta Coradini, who sadly passed away due to cancer last September. The costs come from all 19 "member states" of the ESA, and each citizen from those countries contributes through tax - though each European pays around a quarter of the amount that each American pays to NASA. At around the cost of one cinema ticket per person per year, we're all responsible for the cost of JUICE.
There is also still potential for the project to be renamed. Several members of public interest groups and scientific bodies have suggested running a public competition to find a suitable mission name, and some of the project leaders have suggested granting the permanent name "Laplace", named for a 19th Century mathematician.
The main objectives of the mission are stated as the following: * characterisation of the ocean layers and detection of putative subsurface water reservoirs; * topographical, geological and compositional mapping of the surface; * study of the physical properties of the icy crusts; * characterisation of the internal mass distribution, dynamics and evolution of the interiors; * investigation of the exosphere; * study of Ganymede's intrinsic magnetic field and its interactions with the Jovian magnetosphere.
Despite this, the reported focus has been on one particular aspect. "Juice will give us better insight into [the moons'] potential for hosting life," stated Professor Alvaro Giménez Cañete, an ESA Director. UCL's Professor Andrew Coates, added that "studying these watery worlds is the next vital step beyond Mars in the search for the conditions for life," with Dr Emma Bunce of the University of Leicester adding that "Ganymede [has a] unique place in the Solar System."
Professor Michele Dougherty of ICL University (the third and final British partner) explained in greater depth: "There are four conditions required for life to form. You need water; you need an energy source - so the ice can become liquid; you need the right chemistry - nitrogen, carbon, hydrogen; and the fourth thing you need is stability - a length of time that allows life to form. The great thing about the icy moons in the Jupiter system is that we think those four conditions might exist there; and Juice will tell us if that is the case."
For more information on JUICE, visit the ESA website.