Solar Orbiter: Exploring the Sun-Heliosphere Connection

Understanding the connections and the coupling between the Sun and the heliosphere is of fundamental importance to addressing one of the major scientific questions of ESA’s Cosmic Vision 2020 programme: “How does the Solar System work?” The heliosphere also represents a uniquely accessible domain of space, where fundamental physical processes common to solar, astrophysical and laboratory plasmas can be studied under conditions impossible to reproduce on Earth, or to study from astronomical distances. The results from missions such as Helios, Ulysses, Yohkoh, SOHO, TRACE and RHESSI, as well as the recently launched Hinode and STEREO missions, have formed the foundation of our understanding of the solar corona, the solar wind, and the three-dimensional heliosphere. Each of these missions had a specific focus, being part of an overall strategy of coordinated solar and heliospheric research. However, an important element of this strategy has yet to be implemented. None of these missions have been able to fully explore the interface region where the solar wind is born and heliospheric structures are formed with sufficient instrumentation to link solar wind structures back to their source regions at the Sun. This is the overarching goal of Solar Orbiter. With previously unavailable observational capabilities provided by the powerful combination of in-situ and remote sensing instruments, and the unique inner-heliospheric mission design specifically tailored for the task, Solar Orbiter will address the central question of heliophysics: How does the Sun create and control the heliosphere? In this paper, we will present the detailed science goals of the mission and briefly review its status.