Mobile Suit Gundam: Char's Counterattack (1988)

Amuro and Char, two best mobile suit (robotic weapons) pilots who fought together against Titans after the Zeon's independence war, must face each other in a fateful duel where the Neo Zeon, led by Char, attempts to drop a gigantic asteroid and its nuclear weapons to Earth in order to cause Nuclear Winter to wipe out the Earth inhabitants.