ESA JUICE and NASA Europa Clipper: Joint Science Opportunities during Cruise and Jupiter Approach

ESAs JUpiter ICy moons Explorer (JUICE) launched on April 14, 2023, beginning an eight-year journey to the Jupiter system. Arriving in 2031, JUICE will make 35 total flybys of Ganymede, Europa, and Callisto before going into orbit about Ganymede. NASAs Europa Clipper is scheduled to launch in October 2024, arriving in the Jupiter system in 2030, a year ahead of JUICE. Clipper will spend a year in the system before undertaking 49 flybys of Europa during a nominal three-year primary mission phase, while also making multiple serendipitous flybys of Ganymede and Callisto. Having two highly instrumented spacecraft in close proximity in time and space affords unprecedented opportunities for synergistic observations during the missions main orbital phases, and unique heliospheric and magnetosphere science during cruise and Jupiter approach. While there are currently no firm commitments from NASA or ESA to accomplish science beyond that of each missions primary science objectives, discussions are ongoing and the task of the appointed JUICE-Clipper Steering Committee (JCSC) is to provide recommendation of compelling joint science opportunities between the two missions. This paper will focus on the cruise and Jupiter approach phases. We have identified a number of potential opportunities for investigating the evolution of the solar wind plasma and interplanetary magnetic field and related structures such as monitoring Coronal Mass Ejections (CMEs) or Corotating Interaction Regions (CIRs) during times when the two spacecraft are radially aligned (i.e. at similar heliocentric longitudes) or at similar heliocentric distances, as well as radio science observations of the solar wind and/or Solar Energetic Particle (SEP) events that could be observed throughout interplanetary transfer. There is also potential for investigating the evolution of solar wind structures and disturbances when both spacecraft are connected through Parker Spiral field lines. The cruise science return from JUICE and Clipper could be further enhanced by data from other operational spacecraft (e.g., BepiColombo, Solar Orbiter, Parker Solar Probe, MAVEN, IMAP, Psyche), thus expanding the catalogue of opportunities for these identified configurations, as well as simultaneous observations by ground and space-based observatories (e.g., JWST, Keck, etc.). The >1 year Jupiter approach phase of the JUICE spacecraft while Clipper orbits within the jovian magnetosphere provides an unrivalled opportunity to study the complexity of the solar wind-magnetosphere interaction and aurora at Jupiter, a topic where there remain many open questions. This phase would provide a unique opportunity for preparatory joint observations to understand if and how the solar wind influences the moons local space environment, and the related interaction with Jupiters rapidly rotating magnetosphere.