The document discusses open source software (FOSS), including its philosophy of freedom and transparency. It outlines the four essential freedoms of open source as defined by the GNU project: freedom to run software for any purpose, study and modify its code, redistribute copies, and distribute modified versions. Key values of open source include freedom, transparency, extensibility, collaboration and innovation. Examples are given of successful open source operating systems, servers, programming languages, and digital content. The document also discusses organizations that support open source development and provides secondary sources for finding open source projects. It outlines reasons why NASA uses open source software and examples of open source databases and distributed computing tools. Finally, it briefly describes the open source robotics platform U