The Jupiter Icy Moon Explorer (JUICE) is a planned European Space Agency (ESA) spacecraft to visit the Jovian system, focused on studying three of Jupiter's Galilean moons: Ganymede, Callisto, and Europa (excluding the more volcanically active Io). It will characterise these three worlds, all of which are thought to have significant bodies of liquid water beneath their surfaces, making them potentially habitable environments. The selection of this mission for the L1 launch slot of ESA's Cosmic Vision science programme was announced on May 2, 2012.
A proposed timeline is launch in 2022 on an Ariane 5 carrier rocket and arrival at the Jupiter system in 2030. By 2033 the spacecraft should enter orbit around Ganymede, after completing various manoeuvres around Jupiter and the other moons. Proposed instruments include cameras, spectrometers, and an ice-penetrating radar.
The Jupiter Icy Moon Explorer (JUICE) would perform detailed investigations on Ganymede as a planetary body and evaluate its potential to support life. Investigations of Europa and Callisto would complete a comparative picture of these Galilean moons. The three moons are thought to harbour internal liquid-water oceans, and so are central to understanding the habitability of icy worlds.
The main science objectives for Ganymede, and to a lesser extent for Callisto, are:
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;
For Europa, the focus is on the chemistry essential to life, including organic molecules, and on understanding the formation of surface features and the composition of the non-water-ice material. Furthermore, JUICE will provide the first subsurface sounding of the moon, including the first determination of the minimal thickness of the icy crust over the most recently active regions.
The main spacecraft design drivers are related to the large distance to the Sun, the use of solar power, and Jupiter's harsh radiation environment. The orbit insertions at Jupiter and Ganymede and the large number of flyby manoeuvres (more than 25 gravity assists, and two Europa flybys) requires the spacecraft to carry about 3,000 kg (6,600 lb) of chemical propellant.
On 21 February 2013, after a competition, 11 instruments were selected by ESA, which will be developed by scientific and engineering teams from all over Europe, with participation from the USA and Japan:
Jovis, Amorum ac Natorum Undique Scrutator
The JANUS camera system will image Ganymede and important parts of the surface of Callisto better than 400 m/pixel (resolution limited by mission data volume). Selected targets will be investigated in high-resolution with a spatial resolution from 25 m/pixel down to 2.4 m/pixel with a 1.3 degree field of view. The camera system has 13 panchromatic, broad and narrow-band filters in the 0.36 µm to 1.1 µm range, and provides stereo imaging capabilities. JANUS will also allow relating spectral, laser and radar measurements to geomorphology and thus will provide the overall geological context.
MAJIS is a visible and infrared spectrometer operating from 0.4 to 5.7 µm, with spectral resolution of 3–7 nm, that will observe tropospheric cloud features and minor species on Jupiter and will investigate the composition of ices and minerals on the surfaces of icy moons. The spatial resolution will be up to 25 m on Ganymede and about 100 km on Jupiter.
Principal investigator: Y. Langevin, Institut d'Astrophysique Spatiale, France
UVS is an imaging spectrograph operating in the wavelength range 55–210 nm with spectral resolution of < 0.6 nm that will characterise exospheres and aurorae of the icy moons—including plume searches on Europa, study the Jovian upper atmosphere and aurorae. It will reach a resolution of 0.5 km observing Ganymede and up to 250 km observing Jupiter.
SWI is a spectrometer using a 30 cm antenna and working in 1080–1275 GHz and 530–601 GHz with spectral resolving power of ~107 that will study Jupiter's stratosphere and troposphere, and the exospheres and surfaces of the icy moons.
RIME is an ice-penetrating radar working at frequency of 9 MHz (1 and 3 MHz bandwidth) emitted by a 16 m antenna that will be used to study the subsurface structure of Jovian moons down to 9 km (5.6 mi) depth with vertical resolution up to 30 m in ice.
RPWI will characterise the plasma environment and radio emissions around the spacecraft, it is composed of four experiments: GANDALF, MIME, FRODO and JENRAGE. RPWI will use two Langmuir probes sensitive up to 1.6 MHz to characterize plasma and receivers in the frequency range 80 kHz – 45 MHz to measure radio emissions.
Gravity & Geophysics of jupiter and Galilean Moons
3GM instrument, composed of a Ka transponder and an ultrastable oscillator, will measure the gravity field of Ganymede and the extent of internal oceans. It will also study the ionosphere and upper atmosphere of Jupiter and other Jovian moons.
Planetary Radio Interferometer & Doppler Experiment
PRIDE experiment will generate specific signals transmitted by JUICE antenna and received by Very Long Baseline Interferometry to perform precision measurements of the gravity fields and of Jupiter and the icy moons .