First Weather System Follow-on (WSF) satellite. WSF-M (Weather System Follow-on – Microwave) is the next-generation operational environmental satellite system for the Department of Defense (DoD), to replace the microwave wavelength weather forecasting capabilities of the DMSP satellites. Ball Aerospace has been selected in late November 2017 to be the prime contractor for 2 Low Earth Orbit (LEO) weather satellites with a passive microwave imaging radiometer instrument and hosted Government furnished energetic charged particle (ECP) sensor space weather payload developed by the Air Force Research Laboratory. The radiometer leverages the Ball-built Global Precipitation Measurement (GPM) Microwave Imager (GMI) instrument. This mission will improve weather forecasting over maritime regions by taking global measurements of the atmosphere and ocean surface.