The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Integrated Program Office (IPO) Calibration and Validation (Cal/Val) effort faces opportunities and challenges unique for a satellite program. The diverse applications of the customers, ranging from real-time military operations support to forecast model input and long-term climate research, complicate decisions regarding acceptable levels of performance and resource allocation. In addition, the Environmental Data Records (EDRs) and Intermediate Products (IPs) from each sensor cover a wide range of environmental monitoring disciplines and require the development of a variety of tools and data using a limited budget. Conversely, the sensors and algorithms have been designed to complement each other where possible, and the program can heavily leverage heritage programs such as NASA's Earth Observing System and European Organisation for the Exploitation of Meteorological Satellites Meteorological Operational satellite for algorithm and sensor validation. This paper will focus on how the NPOESS Cal/Val program will leverage existing resources, identify additional resources needed, and engage the user and academic communities to insure the NPOESS Cal/Val effort is sufficient for the Government's role of independent verification and validation for the NPOESS program.