Now and again scientists think of interesting ways to use our space missions in contexts for which they were not designed. I’m thinking, for example, of the ‘pale blue dot’ image snapped by Voyager 1 in 1990, an iconic view that forcibly speaks to the immensity of the universe and the smallness of the place we inhabit. Voyager’s cameras, we might recall, were added only after a debate among mission designers, some of whom argued that the mission could proceed without any cameras aboard.

Fortunately, the camera advocates won, with results we’re all familiar with. Now we have a project out of The SETI Institute that would use a European Space Agency mission in a novel way, one that also challenges our thinking about our place in the cosmos. Daniela de Paulis, who serves as artist in residence at the institute, is working across numerous disciplines with researchers involved in SETI and astronautics to create A Sign in Space, the creation of an ‘extraterrestrial’ message. This is not a message beamed to another star, but a message beamed back at us.

The plan is this: On May 24, 2023, tomorrow as I write this on the US east coast, ESA’s ExoMars Trace Gas Orbiter, in orbit around Mars, will transmit an encoded message to Earth that will act as a simulation of a message from another civilization. The message will be detected by the Allen Telescope Array (ATA) in California, the Green Bank Telescope (GBT) in West Virginia and the Medicina Radio Astronomical Observatory in Italy. The content of the message is known only to de Paulis and her team, and the public will be in on the attempt to decode and interpret it. The message will be sent at 1900 UTC on May 24 and discussed in a live stream event beginning at 1815 UTC online.

The signal should reach Earth some 16 minutes after transmission, hence the timing of the live stream event. This should be an enjoyable online gathering. According to The SETI Institute, the live stream, hosted by Franck Marchis and the Green Bank Observatory’s Victoria Catlett, will feature key team members – scientists, engineers, artists and more – and will include control rooms from the ATA, the GBT, and Medicina.

Daniela de Paulis points to the purpose of the project:

“Throughout history, humanity has searched for meaning in powerful and transformative phenomena. Receiving a message from an extraterrestrial civilization would be a profoundly transformational experience for all humankind. A Sign in Space offers the unprecedented opportunity to tangibly rehearse and prepare for this scenario through global collaboration, fostering an open-ended search for meaning across all cultures and disciplines.”

The data are to be stored in collaboration with Breakthrough Listen’s Open Data Archive and the storage network Filecoin, the idea being to make the signal available to anyone who wants to have a crack at decoding it. A Sign in Space offers a Discord server for discussion of the project, while findings may be submitted through a dedicated form on the project’s website. For a number of weeks after the signal transmission, the A Sign in Space team will host Zoom discussions on the issues involved in reception of an extraterrestrial signal, with the events listed here.