Yuusha Exkaiser Episode 42: Shoubousha Shutsudou Seyo
Episode 42 of 48 of Yuusha Exkaiser, aired December 8, 1990, 25 minutes. Available with English subtitles and dub where released.
Episode summary
When aliens plan to invade earth, the young Kouta along with a giant robot from outspace named Exkaiser must team up to save the world and his friends.