Whitepaper #249 in the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033. Main topics: space weather applications; basic research. Additional topics: inner heliosphere; other space weather; space-based missions/projects.
The Multi-spacecraft Heliospheric Mission is a versatile mission concept to determine the variations of solar wind streams, transients, and energetic particles in the inner heliosphere and advance our knowledge of how to forecast space weather. MHM fills a clear gap in NASA HSO, identified in the 2003 Decadal Survey and NASA Space Weather Gap Analysis. It can be proposed as a SMEX (MIIST).