The AS-S-8 is an apocalypse class vehicle, meaning it was designed with an apocalypse case scenario (such as nuclear war) in mind. Apocalypse class vehicles are typically quite large and the AS-S-8 is no exception.
It is a large submersible capable of carrying a wide variety of equipment and other assets with places to store food and water, along with filtration systems which remove radioactive particles from both the air and water. It is powered by 3 Thorium reactors and can dive to depths in excess of 1,000ft. The AS-S-8 is capable of supporting a large number of refugees and is capable of defending itself as the sub houses 2 fighter squadrons as well as torpedoes AWACS aircraft and 20 ICBMs.