Due to its stable and unique rotational period, tremendously hostile conditions, and huge exploitable solar power potential, Mercury is the single largest and oldest automated factory hub in human space. Much of the output of the colossal factory complexes is shunted into orbit for use in the construction of new capital ships and orbital habitats in the rest of the system.

Distance from Sol: 0.3AU

Named for an ancient practical joke, the Caduceus listening post is a government-run facility positioned in Mercury's solar shadow. The purpose of the facility is to monitor signals supposedly received from deep within the corona in the late 2200's, but in practice it is considered a joke posting used to punish those that Sol's internal administration has some kind of displeasure with.