NOAA-21 Designated as the Primary Satellite of the JPSS Constellation
During March 2024, NOAA-21 was declared the primary satellite of the Joint Polar Satellite System (JPSS). In early April 2024, NOAA-20 (newly designated as the secondary satellite) completed its orbital shift placing NOAA-20 a half-orbit (~50 minutes) a part from NOAA-21. The tertiary satellite, SNPP, is now positioned a quarter-orbit between NOAA-21 and NOAA-20. A schematic below displays and compares the old JPSS orbital configuration (pre – 20 March 2024) to the finalized orbital configuration (4 April 2024).
For users, how does the new orbital configuration appear in the imagery? A CONUS perspective of VIIRS 11.45 µm swaths from NOAA-21, SNPP and NOAA-20 are seen on 10 April 2024. Notice the JPSS orbital sequence (observed from east coast to west coast) starts with NOAA-21, then ~25 minutes later SNPP, then NOAA-20 ~25 minutes after that. Afterwards, a 50 minute data gap occurs, then the sequence repeats.
The same orbital sequence can also be seen over Alaska. Refer to the 2 May 2024 VIIRS Snow/Cloud Layers animation that shows the sea ice coverage over the Bering and Chukchi Seas and low/high clouds and snow over the Last Frontier State.