Ulysses 1994XF04 was the fourth Ilium Asteroid (Aeolian Camp) and 106th planetoid located in the first half of December 1994. After having been shifted from its Jovian orbit by tidal forces from the Shoemaker-Levy 9 comet it began a degrading elliptical orbit towards the inner solar system. The International Union of Astronomers (IUA) projected it would be on a collision course with Earth, and informed the Osea, Yuktobanian, and FCU governments of this news before running more detailed models. They soon narrowed down the impact point to northern Usea and expected damage to be localized to the continent. While Osea and Yuktobania breathed a sigh of relief and diverted resources away from asteroid interception, the FCU government covertly formed the Emergency Security Authority to begin preparations for intercepting the asteroids and conceiving and enacting contingency plans should it impact.
Ulysses's existence was made public in April 1996, and the ESA enacted strict regulations on communications to impede the spread of misinformation, rationing to preserve supplies for the post-impact period, and higher taxes to collect funds for the FCU's planned Stonehenge Turret Network (STN) project, a battery of eight railguns designed to shoot down the asteroid. Utilizing technologies developed from the FCU's National Missile Defense program, its construction and operation was a joint effort by the FCU and Erusea, which had been in political contention just years prior. Osea and Yuktobania, however, declined to assist, citing significant financial losses incurred due to the Belkan War.
The STN
The ESA's crackdown on civil liberties spurred a strong backlash in the liberal FCU and smaller East Usean states, which turned violent in 1997. Rebel factions in several Usean militaries took up arms when a whistleblower within the ESA announced that nearly 20% of funds intended for use on STN had been diverted to build a continuity of government bunker in North Point that would house government and military leaders during the impact, and that an excess of defense spending was still going to costly projects such as the XB-10, XFA-27, and ZOE protocol that were meant to maintain FCU continental hegemony after the impact.
The rebels captured the North Point bunker and declared it their headquarters while the FCU's and Erusea's civilian leaders were away on a summit in Osea. Usea's militaries formed the Unified Command to coordinate efforts at putting down these rebellions and liberate their civilian leaders, and enjoyed successes in the traditionally autocratic states of West Usea. The rebels maintained popular support in East Usea, however, until they threatened to destroy Stonehenge in an act of desperation as Unified Command forces advanced on Port Edwards. The rebellion was put down, but at a severe cost in resources and human life as well as the destruction of the bunker.
Refugees in Gracemeria
Studies completed in 1998 revealed that Ulysses was porous with a mostly hollow core, and impact projections were revised to show that it would fragment while entering Near Earth Orbit. While this expanded the scope of Ulysses's damage to include Anea, the FCU was subject to Yuktobanian protests that increasing Stonehenge's range would give it unacceptable military applications. Facing this political pressure as well as many more asteroid fragments to deal with, the FCU declared that Stonehenge would only be used to protect its own territory from impacts, which prompted outcries from Erusea and other Usean states that assisted in the railguns' development. Estovakia, meanwhile, attempted to unilaterally develop its own anti-asteroid railgun while the Emmerian government executed large-scale relocation programs to remove citizens from threatened cities.
Ulysses impacted on June 3rd, 1999, after having fragmented into several thousand meteoroids and several dozen large meteors, rather than two large pieces as predicted by the IUA. While Stonehenge successfully destroyed fragments threatening FCU population centers in the East, Erusea was particularly devastated by the sizable Ryker fragment's impact on Farbanti's financial sector. Emmeria and Nordennavik were essentially unscathed, but Estovakia was defenseless against several fragments' damaging its infrastructure and inflicting heavy casualties.
The Ulysses aerosol cloud from space
Ulysses's long-term ramifications were immediately apparent by 2000 being a "year without a summer" in the northern hemisphere, where debris ejected into the atmosphere by impacts formed a stratospheric sulfate aerosol veil blocking out sunlight and decreasing temperatures until summer of 2001. While most developed nations were able to cope with the ensuing decreased agricultural production it significantly hampered Usea's recovery, and greatly contributed to the Refugee Crisis that is generally believed to be the root cause of the Continental War. Estovakia's catastrophic loss of infrastructure increased its polarization after the federal government's collapse and directly led to the Civil War and EE War.
Aside from Ulysses's political fallout, the existential threat of immediate death from a cosmological entity had a profound sociological effect globally, but especially in Usea. This atmosphere, only worsened by apocalyptic imagery such as red snow falling throughout the northern hemisphere in summer of 2000, prompted both increased religiosity and nihilism in Usean people, responsible for ideological polarization throughout the FCU until the Continental War proved a uniting cause.