The NPOESS Preparatory Project (NPP) mission was designed to bridge the gap between the next-generation research environmental satellite data provided by NASA's Earth Observation System (EOS) program and the next-generation operational environmental satellite data to be provided by the NPOESS program.

In addition to operational instruments focused primarily on providing near-real time data for numerical weather forecasting and environmental monitoring, the NPOESS program was to have provided satellite data focused on understanding the Earth's climate system. Recent changes in the NPOESS program have reduced the emphasis on data and instruments solely focused on understanding climate questions. Changes expected in the NPOESS program, how they affect our ability to answer climate change questions, and the climate capabilities of the restructured NPOESS program will be presented.