Whitepaper #316 in the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033. Main topics: space weather applications; basic research. Additional topics: space weather research/operations/research loop; solar physics; space-based missions/projects.
Key solar physics projects rely on complete, up-to-date full-surface maps for the photospheric magnetic field. These projects are frustrated because the maps unavoidably contain out-of-date, inaccurate information. This problem cannot be solved without full-surface observational coverage. A multi-satellite mission providing vantage points in the ecliptic plane and in polar orbits is needed.