Larsa is Assyria IV-1, the first and largest moon of Shamash. Almost the size of Earth, Larsa is the most populous planet in the system with 5.4 billion inhabitants.
Physical Geography
The moon has a structure and chemistry typical of a terrestrial planet, with a metallic core. There is a substantial amount of nickel compounds on the surface, giving it a dominantly greenish-black color and low albedo. The atmospheric pressure is below the Armstrong limit and contains poisonous metal carbonyls and substantial carbon monoxide. There are substantial uranium deposits and a number of fossil naturally-occuring fission reactors. The planet appears to have had a more substantial atmosphere and liquid water in its geological past.
Larsa is volcanically active.
The surface gravity is about 65% of Earth gravity.
History and Culture
The population was established in the Imperial era by religiously-motivated colonists of a syncretic Christian denomination. Colonization is mostly in the extensive cave systems, which have been sealed and pressurized for shirtsleeves inhabitation. Ideologically desirous of self-sufficiency, the colonization project built fused-quartz domes and light-pipe systems to bring surface light into the caves for agriculture to reduce dependence on imported fusion reactor components.
During the dark age, the planet remained comparatively prosperous and conducted orbital launches routinely.
Economy
Larsa has a fully developed economy and is one of the more prosperous of the Allied Worlds. It is entirely self-sufficient, though the usual commerce in luxury and high technology items exists. The government, reflecting the ingrained value most Larsan cultures still place on self-sufficiency, has been reluctant to become as fully involved in the interstellar economy as some others, but trade is definitely significant.