Chako  

Luna's father rescued a discarded robotic cat named Chako from being thrown into molten lava, and subsequently rebuilt her as a gift for his daughter. Initially, Luna was not fond of Chako, but later discovered that they shared many similarities and gradually grew to appreciate the robot feline. Chako gained entry onto the space ship for a field trip by sneaking aboard, and has been instrumental in assisting Shingo with various electronic and technical issues.