Whitepaper #451 in the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033. Main topics: basic research. Additional topics: outer heliosphere; space-based missions/projects.
Energetic neutral atoms (ENAs) are created in the solar-interstellar interaction, reflecting properties of the heliosphere. We demonstrate that with a spacecraft near the Sun and another on an interstellar-bound trajectory, the separation between them can be used to detect parallax motion of the Ribbon’s source, and 3D tomography may be used to reconstruct the inner heliosheath source of ENAs.