Solar System Technosignatures: Assessing the Possibility and Limits of Detecting Extraterrestrial Probes in Our Solar System

To the point

T. Joseph Lazio argues that alien probes or artifacts could lie within the Solar System, a possibility rooted in Bracewell’s ideas and reinforced by recent interstellar-object sightings, but current searches yield only crude limits and far more sensitive observations are needed to tighten them.

Solar System Technosignatures
arxiv.org

Solar System Technosignatures

NASA has five robotic space probes on escape trajectories from the Solar System, and the Interstellar Probe concept was considered in the recent U.S. Solar & Space Physics Decadal Survey. While none of these robotic probes will be operational when they reach another star, it is natural to ask whether another civilization also might have sent out interstellar probes. Serious consideration of interstellar probes dates at least to R. Bracewell in the early 1960s, and the discovery of three interstellar objects has rekindled some of that interest. I consider current limits on signatures of extraterrestrial technology in the Solar System, both objects on various orbits (probes) and surface artifacts, using data from planetary exploration and astronomical sky surveys. Perhaps not surprisingly, the completeness to which the Solar System has been searched varies as a function of distance from the Sun.