ORBITING PLANETARY USABILITY SURVEY
In the mid 22nd century, humanity became desperate to find another planet. A series of automated, deep space probes were sent to nearby stars, to search for usable planets. The probes would deliver an orbital lab to candidate planets (ones located a system’s Goldilocks Zone). The orbital labs would search for signs of habitability- oxygen, nitrogen atmosphere, water, plantlife, etc.
As soon as livable conditions were found, the probe would send its results back to its OPUS mothership which would then send back the chain from one OPUS mothership to another, relaying its way back to Earth. To cut down on possible errors or misinterpretations, livable criteria being met would result in a single word sent back to Earth: Garden/Eden/Paradise?
2174: OPUS 14 launches 6 probes into the Proxima Centauri Tr-Star system. After 18 years, the word was finally received back on earth from the probe sent to P. Centauri B.
The 2nd and 3rd stages of the program could commence- with automated supply ships launched in advance, then manned crew of terraforming workers, etc.
Finally, colonists would depart for the planet some 32 years later arriving after another 2 decades.