Mihoshi Akeno (明野美星) is a cheerful girl who is one year older than Saku, though has a tendency to act childish. She is very enthusiastic about, and has a strong love for, the universe; a trait passed down from her late father. She has always enjoyed going outside and stargazing or doing other activities, and would usually take Saku along with her, often against his will. She is thrilled to be reunited with her childhood friend Saku and convinces him to join the Astronomy Club at school.