ICARUS: in-situ studies of the solar corona beyond Parker Solar Probe and Solar Orbiter
Authors: Krasnoselskikh Vladimir , Tsurutani Bruce T. , Dudok de Wit Thierry , Walker Simon , Balikhin Michael , Balat-Pichelin Marianne , Velli Marco , Bale Stuart D. , Maksimovic Milan , Agapitov Oleksiy , Baumjohann Wolfgang , Berthomier Matthieu , Bruno Roberto , Cranmer Steven R. , de Pontieu Bart , Meneses Domingos de Sousa , Eastwood Jonathan , Erdelyi Robertus , Ergun Robert , Fedun Viktor , Ganushkina Natalia , Greco Antonella , Harra Louise , Henri Pierre , Horbury Timothy , Hudson Hugh , Kasper Justin , Khotyaintsev Yuri , Kretzschmar Matthieu , Krucker Säm , Kucharek Harald , Langevin Yves , Lavraud Benoît , Lebreton Jean-Pierre , Lepri Susan , Liemohn Michael , Louarn Philippe , Moebius Eberhard , Mozer Forrest , Nemecek Zdenek , Panasenco Olga , Retino Alessandro , Safrankova Jana , Scudder Jack , Servidio Sergio , Sorriso-Valvo Luca , Souček Jan , Szabo Adam , Vaivads Andris , Vekstein Grigory , Vörös Zoltan , Zaqarashvili Teimuraz , Zimbardo Gaetano , Fedorov Andrei 
Published: February 2023

The primary scientific goal of ICARUS (Investigation of Coronal AcceleRation and heating of solar wind Up to the Sun), a mother-daughter satellite mission, proposed in response to the ESA “Voyage 2050” Call, will be to determine how the magnetic field and plasma dynamics in the outer solar atmosphere give rise to the corona, the solar wind, and the entire heliosphere. Reaching this goal will be a Rosetta Stone step, with results that are broadly applicable within the fields of space plasma physics and astrophysics. Within ESA’s Cosmic Vision roadmap, these science goals address Theme 2: “How does the Solar System work?” by investigating basic processes occurring “From the Sun to the edge of the Solar System”. ICARUS will not only advance our understanding of the plasma environment around our Sun, but also of the numerous magnetically active stars with hot plasma coronae. ICARUS I will perform the first direct in situ measurements of electromagnetic fields, particle acceleration, wave activity, energy distribution, and flows directly in the regions in which the solar wind emerges from the coronal plasma. ICARUS I will have a perihelion altitude of 1 solar radius and will cross the region where the major energy deposition occurs. The polar orbit of ICARUS I will enable crossing the regions where both the fast and slow winds are generated. It will probe the local characteristics of the plasma and provide unique information about the physical processes involved in the creation of the solar wind. ICARUS II will observe this region using remote-sensing instruments, providing simultaneous, contextual information about regions crossed by ICARUS I and the solar atmosphere below as observed by solar telescopes. It will thus provide bridges for understanding the magnetic links between the heliosphere and the solar atmosphere. Such information is crucial to our understanding of the plasma physics and electrodynamics of the solar atmosphere. ICARUS II will also play a very important relay role, enabling the radio-link with ICARUS I. It will receive, collect, and store information transmitted from ICARUS I during its closest approach to the Sun. It will also perform preliminary data processing before transmitting it to Earth. Performing such unique in situ observations in the area where presumably hazardous solar energetic particles are energized, ICARUS will provide fundamental advances in our capabilities to monitor and forecast the space radiation environment. Therefore, the results from the ICARUS mission will be extremely crucial for future space explorations, especially for long-term crewed space missions.