National Aeronautics and Space Administration (NASA). This NASA Goddard Procedures and Guidelines. Effective Date: October 26, 2001. Expiration Date: October 26, 2006. 7 p. This document, Goddard Management of Principal Investigator (PI) Mode Missions, describes the roles and responsibilities of the PI, Goddard as the Lead Center for Earth and Space Science Programs, the Program Office, the Implementing Organization, and NASA Headquarters (HQ) with respect to the overall management of PI-Mode missions at the Goddard Space Flight Center (GSFC). These guidelines are consistent with NPG 7120.5, NASA Program and Project Management Processes and Requirements, which allows for tailoring of requirements according to mission size, complexity, criticality, and risk.