Whitepaper #116 in the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033. Main topics: basic research. Additional topics: outer heliosphere; space-based missions/projects; emerging opportunities.
A near-term Interstellar Probe would enable in-situ measurements of the interstellar gas all the way from the Earth to the heliosheath and beyond the reaches of the heliopause. These revolutionary measurements would reveal how the interstellar medium is filtrated and deflected by our heliosphere and the chemical and isotopical composition of the interstellar medium itself.