Interplanetary War

The Interplanetary War was a very large armed conflict waged throughout the Sol system between 2164 and 2170. It was fought among the United Nations; the neo-communist Koslovics, led by Vladimir Koslov; the fascist Frieden, backed by corporations of the Unified German Republic; and a number of other national governments. The fighting was the culmination of four prior years of war which included the Jovian Moons Campaign, the Rainforest Wars, and the Mars Campaign. Together with the Interplanetary War proper, these conflicts are sometimes collectively referred to as the Interplanetary Wars.

Background
As overpopulation and unrest mounted on Earth, a number of new political movements were formed, including the Koslovics and the Jovian Frieden movement. The Frieden attacked United Nations colonial advisers on Io, one of the moons of Jupiter, and UN-sponsored military forces began a pattern of massive buildups which culminated with the Interplanetary War. Along with these buildups the UN used its increasing power to bring Earth's national governments under its power, forming the United Nations Space Command, which combined Earth's distributed national militaries into a single, fully organized force. After a successful UNSC Marine attack on Mars recruitment drives and propaganda tactics strongly bolstered the UNSC's military.

The assault on Mars marked the beginning of a systematic and dedicated campaign to crush the remnants of the rebel forces on the various planets and outposts they held in the Sol system. Ultimately, Frieden and Koslovic forces were defeated in the face of a massive, unified, inspired, and very powerful UN military. The year 2170 marked the end of the Interplanetary War with the Callisto Treaty, with the Koslovic and Frieden commanders formally surrendering to the UNSC.

The war saw the first military applications of bioaugmentation protocols, already used outside the military to adapt humans to the conditions of space and different colonial habitats. These augmentations would serve as an early precursor to the enhancements used in the ORION Project and the subsequent SPARTAN programs. Spacecraft-borne nuclear weapons were also first employed during these conflicts.

Aftermath
The Unified Earth Government was constituted as humanity's governing body by the UN in the immediate wake of the conflicts in 2170. After the war the UNSC were forced to deal with a less obvious but equally serious threat: overpopulation and a massive military that has no enemy to fight. The post-war period saw massive population surges that, coupled with the destruction and famine bred by the Rain Forest Wars, threatened to destabilize the interplanetary economy.

Humanity would not be able to expand beyond the confines of the Solar System until nearly two centuries later, with the discovery of slipspace travel in 2291 and the subsequent formation of the first Inner Colonies in 2362. Through interstellar colonization humanity would enter a new golden age, with its massive population stabilized across many off-system worlds and goods transported to Earth from the colonies.

2158

 * The Frieden movement destroys an embassy in the Europan city of Thynia. In response, the United Nations labels the Friedens as terrorists and dispatches UN colonial advisors to Io to help organize policing efforts.

2160

 * Jovian Moons Campaign: Secessionist forces, mostly Frieden rebels, attack UN colonial advisers on Jupiter's moon Io. This leads to several months of fierce fighting between UN forces and Frieden rebels on the Jovian moons. Though it is not the first such engagement it is one of the bloodiest, leading other Earth governments to fight proxy wars off-planet and throughout the Solar system. This soon leads to the Rainforest Wars.

2161

 * Late 2161: By this time, the Jovian Moons Campaigns had subsided; the bloodshed ceased for several months. Many believed that the worst of the fighting had past.

2162

 * February: A series of bombings in South America ignites a nineteen-month conflict, known as the Rainforest Wars. The fighting would eventually spread across the entire continent. As the conflict rages, more violence is sparked throughout the Sol system.
 * Unknown
 * Battle of Delambre: Friedenists and Neo-Friedenists clash over internal differences on Luna.

2163

 * November: The leader of the Frieden movement, Nadja Mielke, is assassinated on her way to a command center in the Europan city of Pelagon.
 * December: The Friedens retaliate against the Koslovics at Argyre Planitia, Mars, destroying the city in a matter of hours. The Koslovics retreat to the city's outskirts, where the fighting continues in the weeks that followed.

2164

 * January: In response to the violence on Mars, the United Nations launches various lightning strikes against Koslovic forces in the Argyre Planitia. This is the first extraterrestrial deployment of the newly established UNSC Marine Corps. The Mars Campaign would last for two full years, as the UNSC bombed Koslovic remnants, effectively wiping out all Martian oppostion.
 * The United Nations Space Command is established by the United Nations to eliminate the various rebel organizations in the Sol system.
 * The conflict later known as the Interplanetary War had officially begun. The UNSC forces begin a systematic and dedicated drive to crush the remnants of the Frieden and Koslovics throughout the Solar system.

2167

 * Despite heavy losses on Mars, the Koslovics still exist on Luna and parts of Earth.
 * August: Vladimir Koslov and his family are killed in a bombing by Lake Autolycus on Luna, effectively destroying Koslovic leadership. The UNSC denies involvement in the event.

2169

 * The UNSC invades Europa, Io, Ganymede, and Callisto, destroying hundreds of Frieden bases and weapons caches. The Friedens, now led by Nadja Mielke's nephew Oscar Bauer, are crushed and little remains of their movement by mid-2169.
 * The last remaining Frieden and Koslovic leaders are apprehended by the UNSC, bringing the conflict to an end.

2170

 * March: An official ceasefire agreement, the Callisto Treaty is signed, giving the UNSC military jurisdiction of all colonial settlements. The Unified Earth Government is formed in the wake of the conflict, becoming the seat of power for all future colonies.

Trivia
This conflict was never given a proper name prior to the release of the Halo Encyclopedia. Instead, it was referred to simply as "the first real interplanetary war" in both the pre-release Halo: Combat Evolved timeline and the mirrored version on the Halo Wars official website. The title is capitalized as a section heading on the Halo Wars version, though the same is true of the rest of the timeline. Similar to the United Rebel Front, the use of "Interplanetary War" as an official name likely stems from Halopedia, as this wiki once capitalized all article titles as if they were proper nouns.

List of appearances

 * Halo: The Cole Protocol
 * Halo: Evolutions - Essential Tales of the Halo Universe
 * The Impossible Life and the Possible Death of Preston J. Cole
 * Halo: Fleet Battles
 * Halo: Ground Command
 * Halo Mythos