| Primary satellite | Secondary satellite |
| Name | Cosmos 1891 Rocket | COSMOS 1275 DEB |
| Spacetrack catalog number | 18403 | 42198 |
| Radar cross section | large | small |
| Epoch of two-line elements (UTC) | 2021 Jan 17 20:38 | 2021 Jan 01 17:54 |
| Time of closest approach (UTC) | 2020 Dec 01 09:18:08.057 |
| Minimum distance | 7.375 km |
| Height difference | 1.848 km |
| Relative speed | 14.532 km/s |
| Angle between velocity vectors | 162° |
| Geographic position | 38.7°S, 15.1°E |
| Height | 977 km |
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