What is called the Desert Coalition is in fact a failed colony project initiated by the Galactic Commonwealth. The Rezzo and Sippa have long wanted to expand out of their system to new habitable worlds, but have lacked the means to do so. A world had been found that suited their biology by an expedition group and they asked for support from the commonwealth to help them settle a new colony world. It initially made it’s way through the senate and colony ships were designed and built to move the colonists to their new world. The ships were filled and the colonists arrived as planned, however the Sippa and Rezzo had underestimated the effort it takes to establish a colony and they needed more and regular supplies to build up this new world.
At this time the senate turned against them arguing that ships shouldn’t have been built and paid for by the commonwealth for what was a matter between the Rezzo and Sippa governments. The debate went on and the supplies where not sent. The colonists did their best to get by in the harsh conditions of their new world and gave up on getting new supplies from the commonwealth after two decades had gone by. Eventually the Rezzo and Sippa within the commonwealth managed to hire a ship and send some supplies to the world, but by then three decades had passed. What the ship found when it arrived was an anarchy with no real colony to be found anywhere. So the ship returned to the two races and reported their findings. With much anguish and blame for the others in the senate they abandoned their former colony for lack of resources to reestablish order.
Tantalus then became a refuge for those who didn’t operate within the law. It even had several small planetary spaceports built on it’s surface by various parties in the following decades. The Sippa and Rezzo colonists remain the dominant life on the world, but those from dozens of races can be found here at any given time.
The Desert Coalition is sort of a misnomer, their is no unified government on the world of Tantalus. Instead it is a anarchy with a few developing patchwork states among it. This means their is little to no law or legal enforcement which has made it a haven for those disliking the law.
The Desert Coalition maintains a militia military composed of whoever is willing and the space ports are privately owned and usually have their own ‘spaceport defense forces’. They do have some unique aircraft and scavenged ground vehicles, but all their spacecraft are generic designs.