Beginning with the launch of the DMSP F-16 satellite on 18 October 2003, the SSMIS marks the commencement of a new series of passive microwave conically scanning imagers and sounders planned for launch over the next two decades. SSMIS improves upon the surface and atmospheric retrievals of the Special Sensor Microwave Imager (SSM/I) and the SSMIS imaging and sounding sensors share the same viewing geometry, thereby allowing surface parameters to be retrieved simultaneously. The SSMIS instrument is able to estimate atmospheric temperature, moisture, and surface parameters from data collected at frequencies ranging from 19 to 183 GHz over a swath width of 1707 km. SSMIS is currently carried aboard DMSP-F16, -F17, and -F18 satellites, and is slated for future missions aboard DMSP-F19 and -F20.