Mars Simulation Project (mars-sim) is an open source Java project aiming at building computer models that characterize important aspects of establishing human settlements on Mars. What mars-sim attempts to model is the professional relationship of the early settlers. There are jobs to get done in developing the settlement. Therefore, each settler is modelled with personalities, a list of natural attributes and job skills, and a set of preferences (likes-and-dislikes on a bunch of task). The tool defines an assigned role and a job position for each settler with a myriad of tasks to perform. While most tasks are done independently by an individual, some require teaming up with others to get done for the settlement.