The Exploration Pact of 4578 was an agreement entered into by all the nations of planet Earth in AD 4578, forbidding any exploration of Sector Prime in the Milky Way galaxy by an unlicensed starship. No government-sponsored attempts were to be made either until the thorium fission drive was perfected by the Galacticorp Labs on Solace. Each of Earth's five continents developed its own space program and vied for supremacy over the others, awaiting the day when the drive was ready.

The pact was intended to protect Earthlings from incidents with the often hostile and technologically superior races that had already staked claims throughout the Purple Void nebula. It was extremely unpopular, however, and often completely ignored. Citizens of Earth colony Hope rationalized that as the pact was formed by a consensus on Earth and they were no longer technically Earthlings, they did not need to abide by it. The governments of Hope and Earth turned a blind eye to their illegal expeditions while seeking to repeal the pact so that they could turn a profit of their own from the situation.

On January 13th, 4580, less than two years after the pact was signed, infamous smuggler Lextor Mucron financed what was then the most ambitious and blatantly illegal expedition yet; a ten-year journey through the Purple Void by a modified military corvette. Within months of its setting out the pact was repealed so that upon its return the government of Earth could demand a share of its spoils.