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.
Tortoiseshell cats are basically two colors: red and black, along with variations aka dilutes of those colors: lighter shades of red (creams), and lighter shades of black (blues, pale grays), and browns. Torties also come in two types of color patterns: brindled (woven) and patched(solid patches of red or black, (or dilutes of these colors).