- Relationship Voice Actor:
- Ulgar, Kanata and Zack are Kaito, Reiji and Ryoken
- Ulgar and Quiterrie are Seiya and Silphy
- Kanata and Charce are Orga and Iok, Gigina and Gayus, Haruhiro and Manato, Sousuke and Haruka and Shigure and Corrin.
- Kanata and Zack are Kunikida and Hawthorne
- Aries and Yunhua are Yoshino and Kojurou
- Zack, Yunhua and Ulgar are Chiron, Atalanta and Shirou
- Ulgar and Charce are Daisuke and Chang Gai
- Yunhua and Kanata are Yumeko and Ibara
- Quiterrie and Yunhua are Phos and Goshenite
- What Could Have Been: Shinohara's notes in Volume 5 show some early designs and concepts.
- The initial concept was to be a direct homage to the Jules Verne novel Two Years Vacation. As such, the main cast would have fifteen characters note . When the series was set to run for a short term, the cast was pared down to the current nine.
- Kanata's role and personality came from a combination of three scrapped characters:
- Ast, an introverted child described as "un-main character like". This character was scrapped due to his personality type and arc being too much of a creative risk in light of the shortened run.
- Jed, the captain, a dependable senior who takes a fall from grace at the midpoint to make way for Ast's ascension as lead. Scrapped for the same reasons as Ast above. His name would end up being given to Zack's father.
- Neil, an extroverted, expressive young man.
- Quitterie went through several proposed names, the final being what the author liked the sound of the most. Her sharp tongue came from a scrapped character, Marissa. Her complexion also came from scrapped character named Kyla.
- While Zack's design mostly remained unchanged, his traits as The Smart Guy came from scrapped characters Kyla and Tokiro.
- Aries's original name was Patty.
- Charce originally had straight hair and looked younger.
- Ulgar was taller and the author considered giving him a pompadour at one point. He would have been more hotheaded than he was in the final product. His beanie came from Tokiro, a scrapped character.
- Luca would have been more sarcastic and mischievous than he ended up being.
- Funicia would have been a quiet child, but was made into a cheerful one so her traits wouldn't overlap with Yun-hua (who remained mostly unchanged).
- Brandon, described as an overweight lazy complainer, was scrapped due to the author giving up hope that he would be well received by readers. A character resembling him could be briefly seen in Kanata's hiking survival flashback.
Trivia / Astra Lost in Space