While exploring the lunar colony, Kōji encounters Ink, an alien who travels with her father Rubin, both working as repair technicians. This meeting fulfills Kōji's academic interests through direct alien contact. Rubin possesses a rocket ship meticulously built from spare parts over a long period, which later becomes vital to the group's plans. Kōji's connection with Ink facilitates the group's access to this spacecraft.

Kōji's development demonstrates the practical application of his theoretical knowledge when facing authentic space environments and cultures. His adjustment to interstellar society involves navigating bureaucratic processes like obtaining visas and securing employment alongside his peers, grounding his academic passions in tangible realities.

Rubin's rocket ship becomes crucial during the interstellar festival sequence, enabling the group to reach the Pet Star spacecraft for the climactic confrontation. Kōji's role in securing access to this vessel through his friendship with Ink represents a key contribution to the group's objectives.