A Sign in Space: Analogies between the Project and a Real First-Contact Scenario

Abstract On 24 May 2023, a simulated extraterrestrial message was transmitted towards Earth by the Trace Gas Orbiter, a spacecraft of the European Space Agency. The radio signal containing the message was received by several terrestrial radio antennas, as part of the interdisciplinary project “A Sign in Space”. I conceived the project in 2019, and developed it in collaboration with the SETI Institute, the Green Bank Observatory, the Italian Institute for Astrophysics and the European Space Agency. The message designed for the project required one year to be decoded by citizen scientists. The public reaction to the project provides preliminary insights into the unfolding of a concrete First-Contact scenario.