Simultaneous Nadir Overpasses (SNOs) between NOAA-21 and LANDSAT-9
TLE Epoch: 2023 4 25.  Predictions up to the next  14.0 days:

     Date     Time(NOAA-21) NOAA-21 Lat/Lon Date Time(LANDSAT-9) LANDSAT-9 Lat/Lon    Distance(km)  Time Diff(sec)
 04/25/2023   23:51:23   (  70.07, 178.32) 04/25/2023   23:51:46  (  70.05, 178.31)    2.14                23
 04/26/2023   00:42:04   ( -69.94, -14.16) 04/26/2023   00:41:16  ( -69.94, -14.22)    2.37                48
 04/28/2023   15:17:32   ( -70.38, 126.33) 04/28/2023   15:18:43  ( -70.30, 126.90)   23.24                71
 04/28/2023   16:08:12   (  70.06, -65.86) 04/28/2023   16:08:13  (  70.03, -65.84)    3.07                 1
 04/28/2023   16:58:53   ( -69.92, 101.66) 04/28/2023   16:57:43  ( -69.92, 101.63)    1.16                70
 05/01/2023   07:34:16   ( -70.11,-117.46) 05/01/2023   07:35:12  ( -70.13,-117.46)    2.00                56
 05/01/2023   08:25:00   (  70.00,  50.01) 05/01/2023   08:24:39  (  70.02,  50.03)    2.35                21
 05/01/2023   09:15:29   ( -69.23,-141.54) 05/01/2023   09:14:20  ( -69.30,-143.31)   70.32                69
 05/03/2023   23:51:04   ( -70.06,  -1.60) 05/03/2023   23:51:38  ( -70.08,  -1.64)    2.66                34
 05/04/2023   00:41:48   (  69.95, 165.88) 05/04/2023   00:41:05  (  69.97, 165.85)    1.99                43
 05/06/2023   15:17:17   (  70.54, -53.86) 05/06/2023   15:18:27  (  70.43, -52.88)   38.53                70
 05/06/2023   16:07:51   ( -70.03, 114.25) 05/06/2023   16:08:02  ( -70.05, 114.20)    3.01                11
 05/06/2023   16:58:35   (  69.92, -78.28) 05/06/2023   16:57:29  (  69.93, -78.32)    1.82                66
 05/09/2023   07:33:58   (  70.15,  62.54) 05/09/2023   07:34:56  (  70.13,  62.58)    2.36                58
 05/09/2023   08:24:39   ( -70.00,-129.91) 05/09/2023   08:24:26  ( -70.02,-129.93)    2.77                13
 05/09/2023   09:15:12   (  69.31,  38.40) 05/09/2023   09:14:03  (  69.35,  36.80)   63.12                69