Simultaneous Nadir Overpasses (SNOs) between GOES-15 and NPP
TLE Epoch: 2021 6 18.  Predictions up to the next  14.0 days:

     Date     Time(GOES-15)   GOES-15 Lat/Lon  NPP Lat/Lon    Distance(km)  Time Diff(sec)
 06/18/2021   21:52:17   (  -0.04,-128.39) (   0.34,-126.58)  205.48                80
 06/20/2021   10:11:27   (   0.03,-128.46) (   0.78,-131.87)  388.61                80
 06/21/2021   09:52:42   (   0.04,-128.44) (  -0.20,-127.33)  126.15                80
 06/22/2021   22:14:40   (  -0.02,-128.33) (  -1.00,-132.64)  490.68                80
 06/23/2021   21:58:36   (  -0.02,-128.32) (   0.03,-128.11)   23.85                80
 06/26/2021   09:59:02   (   0.02,-128.36) (   0.11,-128.86)   57.04                80
 06/27/2021   09:42:58   (   0.03,-128.34) (  -0.87,-124.33)  457.12                80
 06/28/2021   22:02:15   (  -0.02,-128.22) (  -0.33,-129.63)  160.52                80
 06/29/2021   21:46:10   (  -0.03,-128.20) (   0.65,-125.09)  353.92                80
 07/01/2021   10:05:21   (   0.01,-128.26) (   0.46,-130.38)  240.93                80