Phantasy Star Online Story

A dying planet forces its inhabitants to search for a new livable planet. They start a project named Pioneer Project to send unmanned probes into deep space to search for a new planet. A probe sends back information of a possible planet and they named it Ragol. They launch a large scaled interstellar transport ship called Pioneer 1 to set up a colony on Ragol. Pioneer 1 confirms that Ragol is livable and sets up Central Dome. Seven years later Pioneer 2 reaches orbit of Ragol and open communications with Central Dome. At that moment a large explosion occurs and all contact with the men and women of Pioneer one is lost. What exactly happened on Ragol?

Explosion on Ragol City on Pioneer 2