2023ApJ...957...15A

Assuming civilizations have similar interplanetary communications and radar capability to NASA's Deep Space Network, what is the feasibility of intercepting their communications? Interplanetary conjunctions between Earth-like exoplanets, their stars, and other planets in their systems provide one of the most unique and pragmatic opportunities for detecting technosignatures. While eavesdropping on terrestrial communications becomes limited by a planet's rotation, the beams of satellite communications and interplanetary radar transmissions are tracked, providing the most persistent and powerful opportunity for signal interception. In this study, we present a framework for assessing exoplanet habitability and establishing quantitative bounds for detecting Earth-scale technosignatures from Earth-like planets. These constraints for time, frequency, sky positions, and observatory sensitivity provide recommended observational guidelines for using state-of-the-art and future ground-based radio observatories toward technosignature detection. Applying this framework, 16 exoplanet targets are proposed for radio observation.