The series is based on the popular New York Times bestselling book series collectively known as The Expanse,  written by Daniel Abraham and Ty Franck (under the pen name James S. A. Corey). Abraham and Franck will be show producers.
A tortoiseshell cat is a coat color where the cat is a molted brown cat with black, reddish, or orange patches. They can also have white paws. Tortoiseshell cats have unique genetics. The vast majority of tortoiseshell cats are female, because two X chromosomes are required to produce black, gold and orange coloring.
Although tortoiseshells can be one of many breeds, they tend to have specific personality traits. Tortoiseshell cats tend to be feisty and strong-willed. They are also louder and more dominant than other cats and fiercely independent. They do have positive traits as well, of course.