| Primary satellite | Secondary satellite |
| Name | Cosmos 1908 Rocket | COSMOS 2251 DEB |
| Spacetrack catalog number | 18749 | 34020 |
| Radar cross section | large | small |
| Epoch of two-line elements (UTC) | 2021 Jan 15 10:51 | 2021 Jan 14 21:51 |
| Time of closest approach (UTC) | 2020 Dec 06 01:54:35.605 |
| Minimum distance | 317.581 km |
| Height difference | -2.988 km |
| Relative speed | 12.297 km/s |
| Angle between velocity vectors | 109° |
| Geographic position | 71.0°S, 64.9°W |
| Height | 657 km |
|