Luce Kassel (ルース・カッセル?) is a fictional character who first appeared in Mobile Suit Gundam Side Story: Space, To the End of a Flash. He pilots the RX-78-4 Gundam Unit 4 "G04".
A veteran of Loum, Luce is tasked to the Thoroughbred with the RX-78-4 Gundam Unit 4 "G04" another testbed Gundam of the federation. Luce is supportive to his teammates, frequently encouraging them to do their best in battle and at their jobs. Luce acts as a mentor to Ford Romfellow during the events of the manga up until his death. In his final battle: Luce is forced to use an experimental beam launcher for his Gundam (the RX-78-4) to destroy a Zeon Fleet coming towards Earth. Though he is successful, his Gundam overheats and the left side of the cockpit explodes. Luce is brought back aboard the Thoroughbred but succumbs to his wounds.
- In the game Mobile Suit Gundam: Encounters in Space, during Thoroughbred Mission #03 depending on the player's final score, Luce will either die or survive; if the latter, the missions will go on to the battles of Solomon and A Baoa Qu.