A detailed science and operations analysis of the first flyby of Europa by the Juice spacecraft

Juice is the first large mission chosen in the framework of ESA’s Cosmic Vision 2015-2025 program.

The focus of Juice is to characterize the conditions that might have led to the emergence of habitable environments among the Jovian icy satellites, in particular Ganymede, Europa and Callisto. Juice will also perform a multidisciplinary investigation of the Jupiter system as an archetype for gas giants.

The spacecraft payload consists of 10 state-of-the-art instruments (and one experiment that use the spacecraft telecommunication system with ground-based instruments) that will perform remote and in-situ measurements of Jupiter, its moons and their environment.

 

From a trajectory’s point of view, the mission calls for a three-year orbital survey of the Jupiter system followed by an additional 9 months in orbit around Ganymede for an in-depth characterization of Ganymede as a planetary object and possible habitat. During the Jupiter orbital phase, Juice will perform a sequence of 67 orbits of different periods and inclinations around the planet including several flybys of the Galilean moons, 2 of which as close as 400km altitude from Europa in July 2032.

The Juice top level Europa science goals are the determination of the composition of the non-ice materials and understanding their origin (deep interior vs exogenic), the search for liquid water under active sites and the study of the activity processes at play on the moon.

A representative detailed science operations plan has been developed by the science team covering a 24 hour-period around the first flyby of Europa in July 2032. The plan considers the latest knowledge on instrument and spacecraft resources and performances available at the time of the study.

This work presents the geometry and mission constraints associated to the flyby as well as the observation strategy chosen by the different payload; the remote sensing package’s strategy includes exosphere characterization (including potential plume detection) through limb observations and surface characterization at different scales and wavelengths, both on the inbound (dayside) and outbound (nightside) part of the flyby. At low altitude and centered around closest approach, the geophysics package will perform topography and surface roughness measurement using the laser altimeter as well as surface sounding down to a depth of up to ~ 9 km with the ice penetrating radar. Radio science range rate measurement will support the estimate of the main quadrupole coefficients and the testing of the hydrostatic hypothesis. The in-situ package will operate continuously to monitor the Europa plasma, neutral and electromagnetic wave environment. The resulting harmonized operations timeline, together with resources limitations and the assessment on the expected science return is discussed.