Mobile Suit Gundam MS IGLOO: The Hidden One Year War(2004)

Kidou Senshi Gundam MS IGLOO: 1-nen Sensou Hiwa

The year is Universal Century 0079. Oliver May is a technical officer in the Zeon 603rd Technical Evaluation Unit , in charge of testing new military technology. Stationed in the Jotunheim, a civilian transport ship that was converted into military use, Oliver must head into battle and experience the One Year War, only this time from the perspective of a weapon tester who struggles to make an impact on an evolving war during changing times.

(Source: Anime News Network)