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Mutta Nanba is voiced by Hiroaki Hirata in the anime series Space Brothers. Mutta is the younger brother of the protagonist, Hibito Nanba, and is a former astronaut candidate who initially struggles with self-doubt and insecurity. Hirata's voice acting captures Mutta's complex emotions and his journey of growth and self-discovery as he strives to follow in his brother's footsteps and become an astronaut.