The Heliospheric Constellation (HELICON) mission concept calls for the first constellation of spacecraft to make coordinated measurements of the solar wind magnetic field, plasma and energetic particle distributions and composition in order to determine scale‐lengths of solar wind structures and to resolve ambiguities in temporal and spatial variability. Specifically, HELICON enables the resolution of a wide array of critical questions of solar wind structure and dynamics. The HELICON’s Science Objectives are as follows: (1) Determine the structure and evolution of expanding interplanetary coronal mass ejections, (2) Use supra‐thermal and energetic particles to determine the source populations of solar events and the scale sizes of Interplanetary Coronal Mass Ejections (ICMEs) and Corotating Interaction Regions (CIRs) (3) Determine the structure and nature of the heliospheric current sheet, and (4) Examine the causes of variability in the solar wind. This brief report describes the mission concept and scientific rationale for such a mission. © 2003 American Institute of Physics