You are going to Watch Astro Boy (2003) Episode 3 English dubbed online free episodes with HQ / high quality. Stream Anime Astro Boy (2003) Episode 3 Online English dub Expedition to Mars. After a Mars planetary expedition is undermined by mutineers, Earth sends a follow-up mission under a more reliable commander: Astro Boy. Upon arrival, however, Astro Boy learns that the “mutineers” were actually trying to warn everyone of an impending invasion. When the alien attackers arrive, it is up to Astro Boy to defend Mars against them.