Whitepaper #057 in the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033. Main topics: basic research. Additional topics: planetary ionospheres / upper atmospheres; ground-based missions/projects.
We propose that planetary ionospheres be observed using terrestrial radio transmitters and receivers. Planetary ionospheres have long been recognized as high-value targets, but measurements are scarce. Planets as far as Jupiter may be observable using current technology, while observation of outer bodies requires construction of new systems and creation of temporary holes in Earth’s ionosphere.