Interplanetary War

The Interplanetary War was a 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 also known collectively 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.

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 Rain Forest Wars.

2162
Rainforest Wars: Heavy armed conflict among UN, Koslovic, and Frieden forces erupts in the tropical rainforests of South America. These clashes result from ideological differences and the wish to control important areas on Earth. As the conflict rages even more fighting sparks on moons and other planets in the Sol system.

Battle of Delambre: Friedenists and Neo-Friedenists clash over internal differences on Luna.

2163
Mars Campaign: The UN launch various lightning strikes against Koslovic forces in the Argyre Planitia on Mars. This is the first extraterrestrial deployment of the newly established UNSC Marine Corps. This is later used as a military doctrine in all situations off-planet.

2164
Interplanetary War: The UNSC forces begin a systematic and dedicated drive to crush the remnants of the Frieden and Koslovics throughout the Solar system.

2170
End of the Interplanetary War; the Callisto Treaty is signed. The Unified Earth Government is formed in the wake of the conflict.

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