Based on the Manga of the same time.

Bandai Visual has released the first Teaser for the Gundam Thunderbolt Anime. And here it is.

Anime News Network describes the story as follows:

“The story is set in the same One Year War in UC 0079 as the first Mobile Suit Gundam anime series. It follows the battles between two ace pilots at the “Thunderbolt Sector,” a shoal zone with numerous wrecks of space colonies and warships.”

Via: Anime News Network