| Primary satellite | Secondary satellite |
| Name | Cosmos 1908 Rocket | COSMOS 2251 DEB |
| Spacetrack catalog number | 18749 | 34616 |
| Radar cross section | large | small |
| Epoch of two-line elements (UTC) | 2021 Jan 15 10:51 | 2021 Jan 14 20:13 |
| Time of closest approach (UTC) | 2020 Dec 04 03:49:21.876 |
| Minimum distance | 1817.089 km |
| Height difference | -3.255 km |
| Relative speed | 10.117 km/s |
| Angle between velocity vectors | 84° |
| Geographic position | 80.9°N, 122.6°E |
| Height | 621 km |
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