Union of Allied Planets flag.
The Department of Environmental Studies (DES) is a department of the Union of Allied Planets government. It is responsible for managing the by-product "waste" of terraforming in the form of ionized particle clouds and terraforming nanobots that collect in the Van Allen belts of terraformed planets.
The DES was responsible for the construction of the Cortex Relay Stations, increasing Cortex coverage beyond the Core worlds to the Border and Rim planets.
The department's headquarters is presumably located on the planet Londinium, within the grounds of the Alliance government complex.