Developers: Kidou Senshi Gundam - Before One Year War

Years before the One Year War, Zionic Co. was developing a new type of piloted robots (later became Mobile Suits) using thermonuclear reactor shielded with Minovsky particles as the power source. For safety and secrecy reasons, the project was outsourced to Hosioka, a small steelworks which looked ridiculously lousy at the first sight.

(Source: Anime News Network)