Agent Based Modeling of Collaboration
and Work Practices Onboard the International Space Station
Alessandro Acquisti, Maarten Sierhuis, William J. Clancey, and Jeffrey M. Bradshaw
acquisti@sims.berkeley.edu, msierfhuis@mail.arc.nasa.gov


     The International Space Station is one the most complex projects ever, with numerous interdependent constraints affecting productivity and crew safety. This requires planning years before crew expeditions, and the use of sophisticated scheduling tools. Human work practices, however, are difficult to study and represent within traditional planning tools.  Expedition ship logs highlight recurring discrepancies between planned crew activities and the reality of onboard life. In addition, scheduling constraints make it hard to 'replan' onboard activities. The need emerges for tools able to model the work activities of astronauts onboard the ISS and their interactions with other humans and artificial agents onboard and on earth.  We present an agent-based model and simulation of the activities and work practices of astronauts onboard the ISS. The model represents "a day in the life" of the ISS crew and is developed in Brahms-an agent-oriented, activity-based language used to model knowledge in situated action and learning in human activities.  Brahms links knowledge-based models of activities with discrete-event simulation and a subsumption architecture. In Brahms, agents' behaviors are organized into activities, inherited from groups. Activities are located in time and space. In our model of the ISS work environment we are able to consider issues like resource availability, human/system interaction, both scheduled and unscheduled activities, and the emergence of work practices aboard the ISS out of procedures developed by engineers and mission controllers.