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Design evolution of the NPOESS VIIRS instrument since CDR

This paper summarizes recent design refinements to the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Visible Infrared Imager Radiometer Suite (VIIRS) sensor. These design changes reduced manufacturing and performance risk to meet VIIRS sensor performance specifications. Two key design changes affected mass and optical design. Electro-Magnetic Compatibility (EMC) and Electro-Magnetic Interference (EMI) requirements led to mass growth due to increased shielding and cable complexity. A telescope design modification was required to remove modulated instrument background (MIB) discovered in the Critical Design Review (CDR) optical design. VIIRS risk reduction continues as the Engineering Development Unit (EDU) is assembled and tested in advance of the first flight unit.