How to achieve this victory - Throughout a play session, the player will find clues to sentient alien life. By completing quests, the player will unlock progress towards building a beacon. The beacon sends signals that attract the previous alien inhabitants to the new human life on the planet. The victory condition itself is an homage to Carl Sagan book of the same name.
The first thing to do is find the Progenitor Signal. To get this you must achieve two of the following: Find a fragment of The Signal via an Explorer Expedition on Progenitor Ruins. The chance is slim, but possible. Launch a Deep Space Telescope orbital unit. Build the Transcendental Equation National Wonder.
Then: Decode the progenitor signal with an unnamed National wonder. Build the Contact Beacon. Activate the Contact Beacon with 1000 energy , Wait 20 Turns for the arrival.