The phenomenon known as Climate Change nearly wiped out the human race.
In the mid and late 21st century, a volatile mixture of temperature extremes, super storms and changes in sea level displaced or outright destroyed over a third of the earth's population. Borders shifted and entire countries ceased to be. Add in dwindling resources and it became apparent that mankind had overreached. Even with the full focus of the world's best scientists, early colonization of the Moon and Mars was fragile and frustrating at best. Time was running out.
In 2112 a signal came from outside our solar system, and within that signal were the plans for a space faring vessel far beyond human technology. The scientific breakthroughs that were gleaned just from studying the technology led to over 100 separate advances in modern science and medicine before a single part was built. Advances that led to terraforming, helping to reverse some of the damage done to the earth as well as make the Moon and Mars more hospitable. Advances that resulted in better medicine and living conditions for the overpopulated masses, taking some of the strain off the system. These advances alone would be enough to save humanity, in time, so why had these mysterious extraterrestrials not simply given them that? Why give them the plans for this ship, a ship capable of transporting 100,000 people in stasis at speeds nearing the speed of light? Why help them leave the solar system when they could simply improve it? Humanity would never find out, as the signal had been a one way broadcast pointed directly at the earth. No further communication ever took place.
The unnamed race - dubbed The Givers by humanity - had also included one more thing in the plans. The location of a habitable world just over 9 light years away was the final piece of the transmission that had been received. This planet, four times the size of the earth, seemed to be the reason the plans for the ship had been provided, but many nations were wary of simply packing up and moving to a world they knew nothing of simply on the recommendation of a race of beings that they knew even less about. Instead of pouring all of their resources into building numerous ships and colonizing this new world, they put most of their efforts into repairing the earth and making the Moon and Mars more habitable for expansion.
There was interest in this new world, though, and so one ship was built with the plans provided by The Givers with the intention of traveling to that world and beginning exploration and colonization. At the speed that the ship would be able to travel, it would take almost 10 years to reach this world - commonly called New Eden - with its 100,000 passengers in stasis for the duration, unaging as if frozen in time, and its modest crew in stasis as well unless needed at some point along the journey. Enough food and supplies could be stocked to last the crew the entire 10 years it would take to make the trip, should it come to that, but the civilians would have to remain in stasis.
As the vessel and the trip itself were little more than an afterthought, a token effort to look fully into the gift that had been provided them, it was neither filled with important people nor staffed with the best and brightest. So far, all of the technology had worked perfectly, but there was no guarantee that this ship could do the things that it was supposed to be able to do and be able to complete its mission, and few were willing to take any chances. Even if it did make it all the way, it would be 10 years without aging while friends and family left behind would move on, and another 10 years to come back or bring those friends and family to them. For this reason, the civilian population was chosen largely from the poor, the young and the orphaned, people that had few ties to hold them back and little value to immediately contribute in their current society. Debts and crimes were forgiven in many cases in return for volunteering to be among the 100,000 civilians that would make the trip. While not quite a prison colony, as Australia had once been, it was pretty clear that the numbers consisted of people who would largely not be missed should anything happen to them.
The crew were handled in a similar manner. While anyone could volunteer to serve among the crew, most did so to avoid discharge or reduction in rank for various offenses or failures in duty. Some were the victims of the political machinations of their superiors, either threatened by their potential or crossed in some perceived way. Many who would have been busted down in rank found themselves instead promoted and assigned to serve aboard the vessel, a double edged sword to say the least. A few, either excited by the possibilities or simply lacking any ties to keep them behind volunteered for the mission. In the end, with very few exceptions, the crew were much like the civilian population - capable, but vaguely undesirable for a wide variety of reasons.
In 2122, the construction of the EAV Genesis was completed, and the civilian passengers as well as the crew had been selected and were in place. The Genesis launched amidst much fanfare and celebration that belied the true value that many leaders had given it. In those days leading up to the launch, its passengers and crew were celebrated as heroes and they were happy to play the part, even if they knew the truth. Within days of the ship launching, however, life on earth went back to normal and their heroes were quickly forgotten. Humanity has a short attention span, after all, and it would be 10 years before the EAV Genesis would arrive at New Eden in the Epsilon Eridani system. Soon, they were little more than a footnote in most people's memories.