If you're looking for manga similar to Attack on Titan in the Dome: Heishi-tachi no Hoshizora, you might like these titles.
While looking for the ledgendary Mapman, the last surviving member of the Nomad Star tribe, Lipumira finds him in Tokyo. His name is Gen Tokishima and he is the only one able to get one part of the starmap hidden within the Earth. After retrieving the piece, Gen must make a decision to follow Lipumira in her foolhardy search to find the remaining pieces of the starmap or stay on Earth. He makes his decision, only to find his girlfriend has beaten him to the spaceship as she wants to come as well. Unfortunately, as Gen learns the secret of the starmap, Lipumira's sisters have plans to stop her and will stop her at any cost.
In the far future, there exists a vast region of space that is yet to be explored called the New Space. The levels of new discoveries and dangers are unknown. The Dian sisters, Reina and Rio, made a promise to each other that they will one day journey into New Space together. The two sisters were separated and Reina became a pilot of the commercial luxury cruise liner spaceship Folshion. Rio is a tomboy who seems to have no self consciousness that she is a girl and who finally finds her sister. Rio is allowed to stay on the Folshion granted she finds herself a role on the ship. Sisters united once again, begin dreaming about the adventure into the new territory.
After saying "I wanna go somewhere far away..." in front of Hakase, Yukko and friends are flung into the far reaches of space. They encounter a planet where anything you say becomes real, and enjoy themselves to their hearts' content. But at the same time, Tokisadame City is faced with a fearsome threat?!