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 Europa, Callisto and Ganymede. In addition, JUICE will also perform a multidisciplinary investigation of the Jupiter system as an archetype for gas giants.To address those key science objectives, 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 moon and their environment.From a trajectory's point of view, the mission calls for a three-year orbital survey of the Jupiter System designed as a sequence of 67 orbits around the planet of different periods and inclinations, and includes 35 flybys of Europa (2), Ganymede (12) and Callisto (21). The second part of the mission will devote an additional 9 months in orbit around Ganymede for an in-depth characterization of Ganymede as a planetary object and possible habitat.By its touring nature and due to the diversity of science targets and different disciplines involved in the mission, the development of an observation plan will often face conflicting observations opportunities, also limited in resources as a consequence of the large helio- and geo-centric distances at play.The Science Operations Center, together with the Project Scientist and the Science Working Team, are in charge of setting up and developing a science planning strategy for the mission to ensure that the prime science objectives of the mission are addressed while remaining compatible with the mission constraints.The JUICE Science Planning Process for the Jupiter tour consists of two main pillars:Segmentation of the trajectory. Based on the Cassini heritage, this activity relies on the analysis of all science opportunities along the tour to subsequently support the decision on selecting a prime scientific objective that will get priority in terms of resources (data volume, power and pointing) for a specific time window (a.k.a segment). Taking into account known operational activities' constraints (navigation, wheel off-loading etc) and high-level resources' estimate, an analysis of the expected scientific coverage and resource status along the tour is performed, and several iterations between the different disciplines experts (through the science working groups) take place to converge towards a plan that should ensure that prime science objectives of the mission are fulfilled within the operational constraints of the mission. Detailed sizing case analysis for science operations: For specific operationally of scientifically challenging sections of the segmentation, in-depth analysis is needed in order to refine resources assumptions (attitude, power and data volume) made at segmentation level. Those detailed analysis, performed down to observation level, is done in collaboration with the instrument teams. The present work will describe the different steps and groups involved in the science planning, the current status of the segmentation, and the detailed analysis of the first JUICE Europa flybys will be presented.