Ultraman Cosmos 2: The Blue Planet – Young Musashi Chapter (2002)

Musashi Haruno, a middle school student determined to fulfill his dream of becoming an astronaut – a promise he made to Cosmos – is devastated when a rocket accident halts space development. Just as he's losing hope, a mysterious girl named Shau appears and takes him to a strange, otherworldly place. There, she shows him a vision of his future: ten years from now, Earth is facing destruction at the hands of Sandross, a powerful destroyer from beyond the universe.