Ellen Stardust is the only human on the astronaut squad. She is a volunteer who seeks an adventure to escape from all the sorrows on earth.

Ellen Stardust named herself after her grandmother, Ellena, who raised her alone since she was an orphan. Her last name is Inspired by one of the titles of David Bowie's song that she likes, Lady Stardust.

Ellen spent her childhood with her grandmother made-up stories about Ellen's grandfather. her grandfather was an astronaut who went missing on a mission in outer space. After he died, Ellen's grandmother continues to believe that somehow her grandfather is still alive in outer space, adapting to a new environment and waiting for the right time to come home. The hope continues to grow in her grandmother's made-up stories about outer space and become a reality she perceived as she grew up.

Now that Ellen's grandmother left her alone, there is no reason for Ellen to stay on earth. Deep down in her heart, she wishes she could meet her grandfather through the mission that she will carry out.