The Explorer class ships were the pinnacle of space travel. Twenty years earlier, the space-warp drive made inter-solar distances trivial. We sent missions to Mars, to Jupiter’s moons, to Venus; we even visited Pluto. The Solar System was all within our reach. Then we reached further.
The Explorer Ships weren’t going out a mere ten or twenty light years. The nearest target was four hundred and fifty-six light years away. Rough estimates were the ship would arrive after twelve to fifteen years Earth relative time and crew would experience a few weeks. The exact formula to determine time dilation was variable based on gravity waves and dark-matter density.
The program was conceived as a three-year mission to catalog and explore exoplanets. Explorer ships would be sent out on spiraling paths to explore star systems we could only dream of seeing before. Three years for the crews of the ships. Relative Earth time would be a couple of centuries, still far less than the few millennia it would take with only light speed travel.
When we sent probes to nearby stars with our new space-warp drive we encountered a limitation. The first probe went to a star ten light years away and arrived within a few days. It would take a decade for the probe to transmit any data it collected back to Earth. The obvious fix was to simply have the probe return to the Solar System before transmitting its data. However, having the Explorer Ships return after every star system they explored would hobble the program; at least doubling Relative Earth Time for the crews.
The Explorer Program was stalled until there was a breakthrough. Using a modified space-warp drive we figured out how to pinch two tiny points of space together and transmit across the bridge. It required a sender and receiver to make the connection but once made communication was instantaneous. The program went forward and within seven years the first exploration reports of planets hundreds of light-years away were received. It was the golden age of interstellar exploration.
Then the decline of Earth began.
I was born at the right time to explore the universe. Twenty years later and I might never have made it off the planet or been shuffled to a random colony. Twenty years earlier and I might have been too old for the program or had a family. By the time I had completed my training, the first ten Explorer ships had launched. I left Earth on the fourteenth ship.
We arrived at our third star system and could not initiate contact with Earth. Several hundred light years and twenty-eight years from Earth, we were suddenly cast adrift. For two days we sent the carrier wave, sitting in shifts at the comms panel, waiting for the returning gravimetric pulse to fold space and a human voice to speak to us. The commander decided to make a short five light year jaunt out of the system we were in. This had the benefit of passing a few months of Earth Relative time in minutes for us. This time Earth connected
The Earth Space Agency had been an international organization since before my birth but some legacy facilities had been in use from their NASA days. When the second nuclear missile hit East Texas, the main communication hub was lost. No one knew who had launched the first missiles but the U.S., Russia, China, and France had launched retaliatory strikes at their best guesses.
The Explorer communication outage had lasted several months while the political situation threatened to boil over into a full-scale nuclear war. We never got the full story of who talked who down but a shaky peace was enacted. We returned to the system we had just left and carried out a standard planet survey and a surface survey on a semi-habitable planet. The air was thin but breathable, liquid water on the surface, simple-celled photosynthetic organisms similar to algae.
Two months later of our time, we arrived at the next star system and learned human life on Earth was becoming unsubstantial. The nuclear exchange of a decade ago had accelerated global temperature increases. Within a century humanity would be struggling to survive.
Escaping to the few outposts and colonies on other planets and moons within the solar system was not a sustainable option. Despite several being economically stable, most relied on the Earth for manufactured goods and a portion of their food. Humanity needed to evacuate as many people as possible to exoplanets that could support Earth life. The Explorer Program was retasked with finding planets to send colony ships to.
The crews of the Explorer ships hadn’t expected to return to an Earth they would recognize and now we didn’t expect to return at all. By the time our mission ended, Earth would be abandoned and the worlds we discovered would be home to new branches of humanity.