Ruined Moon of Extinguished Light

"Citizens of Rockwater, yesterday this planet suffered a catastrophic tragedy ... this extinction marks a new, darker era for our world, but ... let me assure you that we will perservere, not only as a city but also as a unified planet. My deepest condolences go out to the countless families and friends of those who were in Starhaven when the disaster occurred."

— Excerpt from a speech given by a prime minister of Rockwater

  Throughout all of Passe-Rath's history, humanity had always looked to their only moon, Light, as a symbol of hope and of their own potential to achieve great things. The largest megacity ever built, Starhaven, covered almost half the moon and was governed by the God-programs Astress and Cosmei. Starhaven served as a neutral ground for negotiations between all the megacities, and a spaceport from where all peoples from all over the galaxy could come and go easily.
However, everything changed when a critical failure within the God-programs' systems caused the reactor powering her to melt down and detonate, destroying Starhaven and everyone in it. Radioactive fallout soon covered the vast majority of the moon, carried by atmospheric winds, and rendered both the city and the moon nigh unlivable. Now, the ruined moon sits in the sky not as a symbol of humanity's potential, but as a testament to their failure.  

History

On Beiryess 3, 1173 BDL, the first lunar probe landed on Light, carrying a small team of Passe-Rath's brightest minds and bravest explorers to test if the conditions on the moon were conducive to life. The results they brought back were exceptional -- conditions were just as good as Passe-Rath, if not better. This spurred a global movement to colonize the planet and make it "humanity's new start," where the megacities' old rivalries and tensions could be left behind in the spirit of fellowship and forming a unified system. It slowly gained momentum after a while; most megacities were skeptical and suspicious at first, but began contributing resources and brainpower after watching Starhaven grow and prosper.
By the time of Saint Aulysses, nearly a century later, Starhaven was a sizable city and attracted much tourist attention from citizens on Passe-Rath. However, as Saint Aulysses and their crew reputedly made contact with numerous solar systems and sentient species, tourists of a new sort started coming to Starhaven, and then to Passe-Rath. Light became the primary checkpoint for interstellar travelers to go through to reach Passe-Rath, and as such, its housing, ship repair, and spaceport capabilities improved greatly. Light was now the symbol of galactic exploration, new beginnings, and diplomacy between both megacities and species.
By the time Starhaven was classified as a megacity and the God-programs were transferred to each megacity on Passe-Rath, the citizens of Starhaven wanted a God-Program of their own. However, all of the megacities had been forced to choose between Passe-Makoa and Rockwater to obtain their God-program, and it would be no different for Starhaven; how could it choose and still stay a neutral party? Additionally, it had been difficult enough transporting the massive amounts of code that comprised the God-programs between each megacity over land, so one more large question stood out -- how was Passe-Rath going to send a God-program into space?

Construction of the Angelglory

The answer to that question was, "a gigantic amount of effort, time, and resources." It took several megacities decades to contruct a data storage device that could contain something as vast as a God-program that could also escape Passe-Makoa's gravity and land safely on Light. However, the problems didn't stop there. The decision to take a copy of the God-program software from either the ordered bloc or the opened bloc seemed to have no correct answer, as it would be seen as favoring each bloc. It was debated countless times over a span of years, but neither Passe-Makoa nor Rockwater could agree. Eventually, it was decided that since a consensus couldn't be reached, the only option left was to send two God-programs to Starhaven -- one from each bloc. This doubled the construction time of the Angelglory, and made the project even more outrageously expensive than it already was, but it preserved the diplomatic neutrality of Starhaven.
Forty-six years after the project was started, the massive computer-ship was finally ready to take off. The entire world held its breath as the Angelglory ignited its rockets and slowly rose into the atmosphere, leaving behind a scorched crater that still exists to this day. It descended into its docking point in Starhaven, a miles-wide barren platform that would prevent civilian casualties in the event something went wrong, and landed. Everyone on both Passe-Rath and Light cheered; watching the Angelglory succeed in its mission was the moment of a lifetime, and marked a new step forward for all of humanity.
The two God-programs onboard, named Astress and Cosmei, awoke when connected to the reactor underneath them and started processing Starhaven's data quickly, maximizing the potential of the great megacity.
Beloved by their citizens, the two God-programs developed their own personalities faster than any of the others down on Passe-Rath. Cosmei became known as the sturdy pillar of Starhaven who supported citizens through tough times, kept the megacity's economy and infrastructure running smoothly, and regulated the harvesting of natural resources on the moon. Conversely, Astress became an icon of big dreams and new ideas; she introduced new concepts to Starhaven, pushed citizens to take risks, and found unorthodox solutions to problems. These two frequently argued -- Astress introduced change, while Cosmei valued stability -- but together, they ran the city like no other God-program did.

Catastrophe

Then, one day, 44 years ago, the massive nuclear reactor that powered both Astress and Cosmei suffered a catastrophic failure. Nobody knows what caused it; theories range from simple error to intentional sabotage to a fight between the two God-programs that couldn't be resolved. The underground chamber was opened for the first time in ages as the God-programs let in engineers and scientists to rapidly fix the problem. For hours, the humans and God-programs worked together furiously to stabilize the reactor, but the meltdown was unstoppable. An evacuation order was sent out to all of Starhaven. However, it was too late -- Only about 0.2% of the population was able to make it off the moon before the reactor detonated, eradicating the center of the city and unleashing deadly radiation over the rest that quickly killed all civilians.
The immediate blast was visible from the surface of Passe-Rath, and left a black scorch mark in the center of the megacity that can be seen to this day. The other side of the moon, relatively unaffected by the explosion, was soon besieged by radioactivity carried by dust on the wind, and most of the wildlife died out.

Fallout

To this day, the levels of radiation on the moon are incredibly lethal, and all attempts to re-colonize have failed. Even on the opposite side of the planet from the core of Starhaven where the reactor detonated, a blanket of radioactive haze prevents life from flourishing.
The immediate reaction after the disaster was fear of the remaining God-programs on Passe-Rath, and the reactors underneath the city center that powered them. Without knowing the cause of the meltdown in Starhaven, people had no idea whether their megacity was next nor how to stop it. Some God-programs completely came to a standstill in their duties to focus solely on scrutinizing their internal systems for any signs of error or sabotage. There was a large flock of people who left the planet in fear of another meltdown.
Weeks turned to months, and aside from a smoldering moon in the sky, everything seemed fine in the megacities. Industry and life slowly returned to normal, and all reactors were running smoothly. However, with the loss of the biggest diplomatic center in the system, tensions between megacities and especially the two blocs were rising again. Additionally, alien visitors whose embassies had been located in Starhaven stopped visiting the planet -- first, the major checkpoint to get to the planet was now an irradiated crater, and second, interstellar news agencies were not yet common and so they had no idea what happened to Light and whether Passe-Rath was safe to visit.

Effects