This rights assessment evaluates the feasibility of converting the contents of WGBH's free online educational resource collection Teachers' Domain (http://www.teachersdomain.org) to open content status. It employs a two-pronged approach -- (1) categorizing and determining licensing costs for the website's already-existing media assets, and (2) researching and identifying challenges and solutions to licensing issues. For this report, WGBH identified all of the media assets and elements (the pieces that comprise a given asset) within the Teachers' Domain science collections, researched the rights holders and licensing agreements associated with each one, and created a classification system to identify rights status. This made it possible to determine the action necessary to shift each asset toward open content status, and to estimate the associated costs (if any). This research also mapped the potential difficulties and the opportunities for progress in this area.