Topic:  NOAA-21 Secondary Satellite in Constellation Declaration 


Date/Time Issued:  November 9, 2023 1630 UTC


Product(s) or Data Impacted: N/A


Date/Time of Initial Impact: November 3, 2023 0000 UTC

Date/Time of Expected End:  N/A

Length of Outage:  N/A

Details/Specifics of Change: 

NOAA’s National Weather Service (NWS) has confirmed that it has assimilated the NOAA-21 sounder data (ATMS and CrIS) in its modeling system and the performance of the VIIRS Imagery product is acceptable, fulfilling the last requirement to declare NOAA-21 as the secondary and the JPSS satellites. As of November 3, 2023 at 0000 UTC assignments are now:

      Primary: NOAA-20

      Secondary: NOAA-21

      Tertiary: S-NPP

When majority of NOAA-21 products reach at least provisional maturity or better, NOAA-21 will be designated the primary satellite and the JPSS satellite assignments will be: 

      Primary: NOAA-21

      Secondary: NOAA-20

      Tertiary: S-NPP

Other messages to the community will be sent regarding NOAA-21 operational product availability as those product provisional milestones occur. The Tertiary designation for S-NPP means any non-nominal issue or ground resource constraint will be worked or addressed under a best-effort basis unless there is a satellite or instrument health and safety issue. 

Please reference the JPSS-2/NOAA-21 Product Operations Plan (POP) for details at:

The contents of this release are subject to change based on user readiness, customer feedback, and management approval. Additional ESPC notifications may provide further details and updates concerning this release.  

Any user feedback and questions should be sent to Shuang Qiu at